Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Organic maturation and source rock potential of Mesozoic and Tertiary strata, Queen Charlotte Islands,.. Vellutini, David 1988

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
[if-you-see-this-DO-NOT-CLICK]
UBC_1988_A7 V44.pdf [ 12.02MB ]
[if-you-see-this-DO-NOT-CLICK]
Metadata
JSON: 1.0052418.json
JSON-LD: 1.0052418+ld.json
RDF/XML (Pretty): 1.0052418.xml
RDF/JSON: 1.0052418+rdf.json
Turtle: 1.0052418+rdf-turtle.txt
N-Triples: 1.0052418+rdf-ntriples.txt
Original Record: 1.0052418 +original-record.json
Full Text
1.0052418.txt
Citation
1.0052418.ris

Full Text

ORGANIC MATURATION AND SOURCE ROCK POTENTIAL OF MESOZOIC AND TERTIARY STRATA, QUEEN CHARLOTTE ISLANDS, BRITISH COLUMBIA BY DAVID VELLUTINI BA.Sc. The University of British Columbia, 1986 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE IN THE FACULTY OF GRADUATE STUDIES (Department of Geological Sciences) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA OCTOBER, 1988 ©David Vellutini, 1988 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, 1 agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver, Canada Date DE-6 (2/88) ABSTRACT The level of organic maturation, thermal history, and source rock potential of Mesozoic and Tertiary strata in the Queen Charlotte Islands have been investigated with vitrinite reflectance measurements (%R°rancf)> numerical modelling (modified Arrhenius and Lopatin models), and Rock-Eval pyrolysis (source rock potential). The level of organic maturation increases from north to south and is primarily controlled by high heat flow associated with plutonism on Moresby Island. Upper Triassic-Lower Jurassic strata are overmature on Moresby Island with vitrinite reflectance values ranging from 2.40 to 5.80 %Roran(j. Jurassic, Cretaceous, and Tertiary strata are immature to overmature on Graham Island with values ranging from 0.15 %Roran(j (Skonun Formation) to 2.43 %R°ran(j (Haida Formation). Constant and variable geothermal gradient thermal regimes were numerically modelled with modified Arrhenius and Lopatin methods. Numerical modelling (assuming constant geothermal gradients) predicts high paleogeothermal gradients (45 to 90 °C/km) for up to 180 million years from the Late Triassic to the Tertiary. Variable paleogeothermal gradient modelling (utilizing a 30 °C/km background geothermal gradient) predicts peak geothermal gradients ranging up to 150 °C/km during Yakoun (183-178 Ma) and Masset (35-10 Ma) volcanism. The timing of hydrocarbon generation was estimated with numerical modelling. The levels of organic maturation for Mesozoic and Tertiary strata reflect the timing of plutonism and associated high heat flow. Triassic strata from west Graham Island and Cretaceous strata from north and south Graham Island entered the oil window during the Early Miocene and are still in the oil window. Jurassic strata in central Graham Island and north Moresby Island entered the oil window during the Bajocian and remain within the oil window. The Skonun Formation is generally immature except for strata at west Graham Island (Port Louis well) and at northeast Graham Island (basal strata in the Tow Hill well) which entered the oil window during the Late Miocene. ii Mean total organic carbon (TOC) contents are generally low (0.06 %) to moderately high (3.6 %) for Mesozoic and Tertiary strata. Some organic-rich horizons with TOC values up to 11.2 % occur in Upper Triassic (black limestone member of the Kunga Group) and Lower Jurassic (Sandilands and Ghost Creek Formations) source strata. Mesozoic and Tertiary strata generally contain gas prone Type III organic matter except for the Lower Jurassic Ghost Creek Formation and the Upper Triassic-Lower Jurassic Kunga Group which contain oil and gas prone Type II organic matter and significant amounts of oil prone Type I organic matter. Lateral variations in TOC and the quality of organic matter (QOM) for Triassic and Jurassic strata are primarily related to the level of organic maturation. The strata have poor to good hydrocarbon source potential on Graham Island. High heat flow associated with plutonism on Moresby Island has overmatured the strata resulting in poor source potential on Moresby Island. Hydrocarbon source potential for Cretaceous and Tertiary strata is primarily controlled by the level of organic maturation and depositional patterns. The Cretaceous Haida and Honna Formation generally contain terrestrially derived Type III organic matter with poor to fair gas source potential. The Skidegate Formation contains a mixture of Types II and III organic matter with decreased (terrestrial) Type III organic matter input and increased Type II (marine) organic matter input relative to the Haida Formation. Cretaceous strata from Moresby Island are generally overmature and have poor source potential whereas equivalent strata from Graham Island are immature to overmature and have fair to moderate gas source potential. Generally immature coal and lignite from the Tertiary Skonun Formation have poor to fair gas source potential. Resinite horizons containing hydrogen-rich organic matter have good oil and gas source potential where mature. Siltstone and shale facies of the Skonun Formation contain moderate amounts of Type II organic matter and have good hydrocarbon source potential. iii TABLE OF CONTENTS ABSTRACT ii LIST OF FIGURES vLIST OF TABLES xviACKNOWLEDGEMENT xx I. INTRODUCTION 1 II. REGIONAL GEOLOGYA. STRATIGRAPHY 4 B. TECTONIC HISTORY 15 C. REFERENCES 8 III. PART I: ORGANIC MATURATION OF MESOZOIC AND TERTIARY STRATA OF THE QUEEN CHARLOTTE ISLANDS 20 A. ABSTRACT 21 B. INTRODUCTION 3 C. METHODS 4 D. RESULTS 25 1. LATERAL VARIATION IN ORGANIC MATURITY 26 2. MATURATION GRADIENTS 82 3. THICKNESS OF ERODED STRATA 84. DEPTH TO THE OIL WINDOW 7 E. THERMAL MODELLING 90 1. BURIAL HISTORIES 1 i. Tertiary Burial Histories 92 ii. Cretaceous Burial Historiesiii. Jurassic Burial Histories 11iv. Triassic Burial Histories 3 2. MATURATION HISTORIES 113. RESULTS AND INTERPRETATIONS 124 i. Tertiary Paleogeothermal Gradients 126 ii. Cretaceous Paleogeothermal Gradients 12iii. Jurassic Paleogeothermal Gradients 127 iv. Triassic Paleogeothermal Gradients4. INTERPRETATIONS OF AREAL MATURATION TRENDS 138 5. TIMING OF HYDROCARBON GENERATION 139 6. HYDROCARBON GENERATION RELATIVE TO TECTONIC ELEMENTS 141 F. DISCUSSION : 142 G. SUMMARY AND CONCLUSIONS 145 iv H. REFERENCES 148 IV. PART II. SOURCE ROCK POTENTIAL OF MESOZOIC AND TERTIARY STRATA OF THE QUEEN CHARLOTTE ISLANDS 151 A. ABSTRACT 152 B. INTRODUCTION 4 C. METHODS 155 1. SAMPLE PREPARATION 152. MEASURED PARAMETERS3. CALCULATED PARAMETERS 156 D. RESULTS 157 1. ORGANIC MATURATION 15E. DISCUSSION 210 1. FACTORS AFFECTING LATERAL VARIATIONS IN SOURCE ROCK QUALITY 243 F. SUMMARY AND CONCLUSION 246 G. REFERENCES 248 V. PART III. APPENDICES 9 A. APPENDIX A (Location Maps for Outcrop and Well Sections) 250 B. APPENDIX B [T (°C) versus Vitrinite Reflectance (%Rorand) Diagrams] 258 v LIST OF FIGURES Figure 1. Location map of British Columbia showing the Queen Charlotte Islands study area 2 Figure 2. Tectonostratigraphic terrane map of western Canada (Armstrong, 1988) 3 Figure 3. Stratigraphic column of Mesozoic and Tertiary strata for the Queen Charlotte Islands (modified from Cameron and Hamilton, 1988) 5 Figure 4. Regional map of the Queen Charlotte Islands showing four plutonic suites (modified from Anderson, 1988): a) Middle to Late Jurassic San Christoval Plutonic Suite (SCPS); b) Oligocene Carpenter Bay Plutonic Suite (CBPS); c) Middle to Late Jurassic Bumaby Island Plutonic Suite (BIPS); d) Oligocene Kano Plutonic Suite 17 Figure 5. Regional surface maturation patterns (%Rorand) of the Upper Triassic grey limestone member (Kunga Group). Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured 27 Figure 6. Regional surface maturation patterns (%Rorand) of the Upper Triassic black limestone member (Kunga Group). Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 29 Figure 7. Regional surface maturation patterns (%Rorand) of the Sinemurian Sandilands Formation. Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation. Maturation gradient is 0.65 log (%Rorancl)/km 30 Figure 8. Regional surface maturation patterns (%Rorand) of the Lower Jurassic Maude Group. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 31 Figure 9. Regional surface maturation patterns (%Rorand) of the Lower Pliensbachian Ghost Creek Formation. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 33 Figure 10. Regional surface maturation patterns (%Rorand) of the Sinemurian Sandilands and Lower Pliensbachian Ghost Creek Formations. Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation. Maturation gradient is 0.65 log ("^Ro^^/km 34 Figure 11. Regional surface maturation patterns (%Rorand) of the Lower Pliensbachian Rennell Junction Formation. Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 35 Figure 12. Regional surface maturation patterns (%Rorand) of the Upper Pliensbachian to Lower Toarcian Fannin Formation. Labelled values do not fit regional trends and are not contoured 36 Figure 13. Regional surface maturation patterns (%Rorand) of the Middle Toarcian Whiteaves Formation. Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured 37 Figure 14. Regional surface maturation patterns (%Rorand) of the Middle Toarcian to Aalenian Phantom Creek Formation 39 Figure IS. Regional surface maturation patterns (%Rorand) of the Lower Jurassic Yakoun, and Moresby Groups 40 Figure 16. Regional surface maturation patterns (%Rorand) of the Upper Valanginian to Barremian Longarm Formation. Dashed line refers to inferred contour. Labelled values do not fit regional trends and are not contoured 42 Vl Figure 17. Regional surface maturation patterns (%Rorand) of the Albian Haida Formation. Values in brackets are minimum and maximum vitrinite reflectances. Maturation gradients are 0.73 and 0.15 log (%Roran£j)/km 43 Figure 18. Regional surface maturation patterns (%Rorand) of the Cenomanian to Turanian Skidegate Formation. Values in brackets are minimum and maximum vitrinite reflectances. Maturation gradients are 0.10 and 0.45 log (%Rorand)/km 44 Figure 19. Regional surface maturation patterns (%Rorand) of the Conacian Honna Formation. Single numbers and numbers in brackets are mean vitrinite reflectance values. Dashed values are minimum and maximum vitrinite reflectance values 45 Figure 20. Regional surface maturation patterns (%Rorand) of the Miocene to Pliocene Skonun Formation. Values in brackets are minimum and maximum vitrinite reflectance values. Maturation gradients range from 0.18 to 0.30 log (%Roran(j)/km 46 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; a) near Moresby Island at Burnaby Island; b) on Moresby Island at Blue Jay Cove; c) on Moresby Island at Carpenter Bay; d) on Moresby Island at Deluge Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation 47 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; e) on Moresby Island at Funter Point; f) on Moresby Island in northeast Poole Inlet at Howay Island; g) on Moresby Island in northeast Poole Inlet; h) on Moresby Island at west Huston Inlet. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation 48 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; i) on Moresby Island at west Huston Inlet; j) near Moresby Island on east Huxley Island; k) near Moresby Island on east Huxley Island 1) near Moresby Island on northeast Huxley Island. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation 49 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; m) on Moresby Island at west Jedway Point; n) near Moresby Island on west Kunghit Island; o) near Moresby Island on west Kunghit Island; p) near Moresby Island at northwest Kunga Island. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+_ standard deviation 50 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; q) on Moresby Island at southeast Rose Inlet; r) on Moresby Island at South Cove in Carpenter Bay; s) on Moresby Island at southwest Huston Inlet; t) near Moresby Island on south Kunga Island. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation 51 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; u) near Moresby Island on south Kunga Island; v) near Moresby Island at Treat Bay on Kunghit Island; w) near Moresby Island on Kunga Island; x) on northwest Graham Island at Sialun Bay. Points are mean vitrinite bars are calculated as mean values standard deviation 52 Figure 22. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Lower Jurassic Maude Group; a) in Skidegate Inlet on Maude Island; b) in Skidegate Inlet on Maude Island; c) in Skidegate Inlet on Maude Island; d) in Skidegate Inlet at Whiteaves Bay. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation 3 Figure 22. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Lower Jurassic Maude Group; e) in Skidegate Inlet on Maude Island; f) in Skidegate Inlet on Maude Island; g) in central Graham Island on the Yakoun River; h) in central Graham Island on the Yakoun River. Points are mean vitrinite values. Error bars are calculated as mean values +_ standard deviation 54 vii Figure 22. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Lower Jurassic Maude, Yakoun, or Moresby Groups; i) in central Graham Island; j) in central Graham Island on the Yakoun River; k) in Skidegate Inlet at Alliford Bay; 1) in Cumshewa Inlet at Robber Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation. Maturation gradient is log (%Roran{j)/km 55 Figure 23. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Cretaceous Haida Formation;a) on northwest Graham Island at south Lauder Point; b) on northwest Graham Island at Caswell Point; c) on northwest Graham Island at Fleurieu Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation 56 Figure 23. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Cretaceous Haida Formation; d) on northwest Graham Island at Caswell Point; e) on northwest Graham Island at Fleurieu Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation. Maturation gradient is log (%Ro^^)/km 57 Figure 24. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Cretaceous Skidegate Formation; a) on northwest Graham Island at south Beresford Bay; b) on northwest Graham Island at north Newcombe Hill; c) on Langara Island at Hart Point; d) on Langara Island at Cox Bay. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation. Maturation gradient is log (%Roran(j)/km 58 Figure 25. Maturation gradients for the Tertiary Skonun Formation. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+_ standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Rorand)/km] is derived from the regression line; a) at the Cape Ball well; b) at the Gold Creek well; c) at the Nadu River well; d) at the Port Louis well 83 Figure 25. Maturation gradients for the Tertiary Skonun Formation. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Rorantj)/km] is derived from the regression line; e) at the Tlell well; f) at the Tow Hill well. Maturation gradients for the Cretaceous Haida Formation; g) at north Lauder Point; h) at Onward Point 84 Figure 25. Maturation gradients for the Jurassic Maude and Yakoun Groups. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Roran{j)/km] is derived from the regression line; i) at Cumshewa Inlet; j) at Rennell Junction. Maturation gradients for the Triassic Kunga Group; k) at Fredrick Island; 1) at Kennecott Point 85 Figure 26. Tertiary Skonun Formation strata at the Cape Ball well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j) t0 facilitate comparison of slopes 93 Figure 26. Tertiary Skonun Formation strata at the Cape Ball well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 35 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 35 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 9&R°ralKj)to facilitate comparison of slopes 94 Figure 27. Tertiary Skonun Formation strata at the Gold Creek well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°rand)to facilitate comparison of slopes 95 viii Figure 27. Tertiary Skonun Formation strata at the Gold Creek well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 40 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j)to facilitate comparison of slopes 96 Figure 28. Tertiary Skonun Formation strata at the Nadu River well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 27 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 27 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to rano facilitate comparison of slopes 9Figure 28. Tertiary Skonun Formation strata at the Nadu River well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 °C/km); 0 maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 9&R°ran(j)to facilitate comparison of slopes 98 Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^>^°ran<j) to facilitate comparison of slopes 99 Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient =55 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 55 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^"^•°nn(i)t0 facilitate comparison of slopes 100 Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 30 C/km) 101 Figure 30. Tertiary Skonun Formation strata at the Tlell well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 32 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 32 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ranc]) to facilitate comparison of slopes 10Figure 30. Tertiary Skonun Formation strata at the Tlell well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=42 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=42 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 <^0^-0lan^) to facilitate comparison of slopes 103 Figure 31. Tertiary Skonun Formation strata at the Tow Hill well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 42 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 42 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ranci)t0 facilitate comparison of slopes 104 ix Figure 31. Tertiary Skonun Formation strata at the Tow Hill well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=51 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 51 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j)to facilitate comparison of slopes 105 Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 88 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 88 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^>R°rand) t0 facilitate comparison of slopes 106 Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 98 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=98 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j)to facilitate comparison of slopes 107 Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 88 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 88 °C/km) 108 Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 70 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^R-°ran(j) to facilitate comparison of slopes 109 Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 80 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 80 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 <^"^-0Tan^) to facilitate comparison of slopes 110 Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km) Ill Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 55 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 55 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R-°ran(j)to facilitate comparison of slopes 114 Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 55 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=55 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^>R°raiK|)to facilitate comparison of slopes 115 Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient=55 C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient=55 °C/km) 116 X Figure 35. Jurassic Maude Formation strata at Rennell Junction (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 45 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient =45 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^R°ran£j)to facilitate comparison of slopes 117 Figure 35. Jurassic Maude Formation strata at Rennell Junction (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=49 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=49 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran<j) to facilitate comparison of slopes 118 Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 90 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient=90 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°rantj)t0 facilitate comparison of slopes 119 Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 100 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 100 C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 <^"^-0Tan^) to facilitate comparison of slopes 120 Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km) : 121 Figure 37. Triassic Sandilands Formation strata at Kennecott Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 65 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 65 C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^,^°rancj) to facilitate comparison of slopes 122 Figure 37. Triassic Sandilands Formation strata at Kennecott Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 70 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 70 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 9&R°ran<j) to facilitate comparison of slopes 123 Figure 38. Cretaceous Haida Formation strata at north Lauder Point (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (130 C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (130 C/km peak geothermal gradient) 128 Figure 38. Cretaceous Haida Formation strata at north Lauder Point (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (140 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (140 °C/km peak geothermal gradient) 129 xi Figure 39. Cretaceous Haida Formation strata at Onward Point (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient) 130 Figure 39. Cretaceous Haida Formation strata at Onward Point (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (145 C/km peak geothermal gradient); 0 maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (145 °C/km peak geothermal gradient) 131 Figure 40. Jurassic Maude Group strata at Cumshewa Inlet (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (97 C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient) 132 Figure 40. Jurassic Maude Group strata at Cumshewa Inlet (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (118 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (118 °C/km peak geothermal gradient) 133 Figure 41. Jurassic Maude Group strata at Rennell Junction (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (83 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (83 °C/km peak geothermal gradient); c) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (105 °C/km peak geothermal gradient); d) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (105- C/km peak geothermal gradient) 134 Figure 42. Triassic Kunga Group strata at Fredrick Island (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient) 135 Figure 42. Triassic Kunga Group strata at Fredrick Island (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (160 C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (160 °C/km peak geothermal gradient) 136 Figure 43. Triassic Kunga Group strata at Kennecott Point (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (100 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (100 C/km peak geothermal gradient); c) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (115 °C/km peak geothermal gradient); d) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (115 °C/km peak geothermal gradient) 137 Figure 44. Surface maturation trends for Mesozoic and Tertiary strata derived from vitrinite reflectance data ((^Roran(j)- Oil window is between 0.50 %Ro . and 1.35 %Ro 143 rand rand xii Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, a) Skonun Formation; b) Honna Formation; c) Haida Formation; d) Skidegate Formation 158 Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, e) Longarm Formation; f) Alliford Formation; g) Newcombe Formation; h) Robber Point Formation 159 Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, i) Graham Island Formation; j) Phantom Creek Formation; k) Whiteaves Formation; 1) Fannin Formation ._. 160 Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, m) Rennell Junction Formation; n) Ghost Creek Formation; o) Sandilands Formation 161 Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, p) black limestone member (Kunga Group); q) grey limestone member (Kunga Group) 162 Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430-435 °C Tmax) to 1.35 %R°rand (465 °C Tmax) define the oil window for Types II and III organic matter, a) Skonun Formation; b) Honna Formation; c) Skidegate Formation; d) Haida Formation 163 Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm C ); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430^135 °C Tmax) to 1.35 %Rorand (465 °C Tmax) define the oil window for Types II and III organic matter, e) Alliford Formation; f) Robber Point Formation; g) Richardson Bay Formation; h) Graham Island Formation 164 Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430-435 °C Tmax) to 1.35 <^°^-°rs:a^ (465 °C Tmax) define the oil window for Types II and III organic matter, i) Phantom Creek Formation; j) Whiteaves Formation; k) Rennell Junction Formation; 1) Ghost Creek formation 165 Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430-435 °C Tmax) to 1.35 %R°rand (465 °C Tmax) define the oil window for Types II and III organic matter, m) Sandilands Formation; n) black limestone member (Kunga Group) 166 Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). Data includes outcrop and well cuttings samples, a) Skonun 3a Formation 167 [HI = S2A-OC (mg HC/gm C^; OI = S3/TOC (mg HC/gm CM. Formation; b) Honna Formation; c) Skidegate Formation; d) Haid  ; Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm Corg); OI = S3/TOC (mg HC/gm corg)l- Data includes outcrop and well cuttings samples, e) Longarm Formation; 0 Alliford Formation; g) Newcombe Formation; h) Robber Point Formation 168 Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm Corg); OI = S3/TOC (mg HC/gm CQr )]. Data includes outcrop and well cuttings samples, i) Richardson Bay Formation; j) Graham Island Formation; k) Phantom Creek Formation; I) Whiteaves Formation 169 xiii Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm Corg); OI = S3/TOC (mg HC/gm CQrg)]- Data includes outcrop and well cuttings samples, m) Fannin Formation; n) Rennell Junction Formation; o) Ghost Creek Formation; p) Sandilands Formation 170 Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); OI = S3/TOC (mg HC/gm CQrg)]. Data includes outcrop and well cuttings samples, q) black limestone member (Kunga Group); r) grey limestone member (Kunga Group) 171 Figure 48. Rock-Eval logs for the Cape Ball well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C TMAX defines the oil window. HI from 0-150 mg HC/gm Cq defines a gas source, HI from 150-300 mg HC/gm CQIg defines a oil and gas source, HI from 300+ defines an oil source. PI valuesfetween 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 172 Figure 49. Rock-Eval logs for the Gold Creek well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm CQr defines a gas source, HI from 150-300 mg HC/gm CQrg defines a oil and gas source, HI from 300+ defines an oil source. PI values fetween 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 173 Figure 50. Rock-Eval logs for the Nadu River well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (Sl + S2)/TOC. 430 (435) °C to 465 °CT defines the oil window. HI from 0-150 mg HC/gm CQr defines a gas source, HI from 150-300 mg HC/gm Corg defines a oil and gas source, HI from 300+ defines an oil source. PI values fetween 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 174 Figure 51. Rock-Eval logs for the Port Louis well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C Tmax defines the oil window. HI from 0-150 mg HC/gm CQr defines a gas source, HI from 150-300 mg HC/gm C defines a oil and gas source, HI from 300+ defines an oil source. PI values fetween 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 175 Figure 52. Rock-Eval logs for the Tlell well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (Sl + S2)/TOC. 430(435) °C to 465 °C Tmax defines the oil window. HI from 0-150 mg HC/gm Cq defines a gas source, HI from 150-300 mg HC/gm CQrg defines a oil and gas source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 176 Figure 53. Rock-Eval logs for the Tow Hill well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C Tmax defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm C defines a oil and gas source, HI from 300+ defines an oil source. PI valuesletween 0.1 and 0.4 define the oil window. Samples are^predominantly coal and lignite with minor siltstone/sandstone from cuttings and core 177 Figure 54. Regional distribution of the mean TOC content for the Skonun Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location 178 Figure 55. Regional distribution of the mean TOC content for the Honna Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Value in brackets are mean TOC. Dashed values are minimum and maximum TOC 179 Figure 56. Regional distribution of the mean TOC content for the Skidegate Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 180 xiv Figure 57. Regional distribution of the mean TOC content for the Haida Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour 181 Figure 58. Regional distribution of the mean TOC content for the Longarm Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 182 Figure 59. Regional distribution of the mean TOC content for the Yakoun and Moresby Groups. Values are mean TOC calculated across the thickness of the formation at each outcrop location 183 Figure 60. Regional distribution of the mean TOC content for the Maude Group. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 184 Figure 61. Regional distribution of the mean TOC content for the Phantom Creek Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location 185 Figure 62. Regional distribution of the mean TOC content for the Whiteaves Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 186 Figure 63. Regional distribution of the mean TOC content for the Fannin Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location 187 Figure 64. Regional distribution of the mean TOC content for the Rennell Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 188 Figure 65. Regional distribution of the mean TOC content for the Ghost Creek and Sandilands Formations. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing TOC 189 Figure 66. Regional distribution of the mean TOC content for the Ghost Creek Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 190 Figure 67. Regional distribution of the mean TOC content for the Sandilands Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing TOC 191 Figure 68. Regional distribution of the mean TOC content for the black limestone member (Kunga Group). Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 192 Figure 69. Regional distribution of the mean TOC content for the grey limestone member (Kunga Group). Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour 193 Figure 70. Regional distribution of the mean QOM [(SI + S2)/TOC] for the Skonun Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location 194 Figure 71. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Honna Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Values in brackets are mean QOM. Dashed values are minimum and maximum QOM 195 XV Figure 72. Regional distribution of the mean QOM [(SI + S2)/TOC] for the Skidegate Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour 196 Figure 73. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Haida Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location 197 Figure 74. Regional distribution of the mean QOM [(SI + S2)/TOC] for the Longarm Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location 198 Figure 75. Regional distribution of the mean QOM [(SI +S2)/TOC] for the Yakoun and Moresby Groups. Values are mean QOM calculated across the thickness of the formation at each outcrop location 199 Figure 76. Regional distribution of the mean QOM [(SI + S2)/TOC] for the Maude Group. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Tick marks on contour line indicate decreasing QOM 200 Figure 77. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Phantom Creek Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location 201 Figure 78. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Whiteaves Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured 202 Figure 79. Regional distribution of the mean QOM [(SI + S2)/TOC] for the Fannin Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location 203 Figure 80. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Rennell Junction Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured 204 Figure 81. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Sandilands and Ghost Creek Formations. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM 205 Figure 82. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Ghost Creek Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM 206 Figure 83. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the Sandilands Formation. Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM 207 Figure 84. Regional distribution of the mean QOM [(Sl + S2)/TOC] for the black limestone member (Kunga Group). Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured 208 Figure 85. Regional distribution of the mean QOM [(SI + S2)/TOC] for the grey limestone member (Kunga Group). Values are mean QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured 209 Figure 86. Surface maturation trends for Mesozoic and Tertiary strata derived from vitrinite reflectance data (%Rorand-see Part I). Oil window is between 0.50 %Rorand and 1.35 %Rorand ; 211 XVI LIST OF TABLES Table IA. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the grey limestone member of the Kunga Group 59 Table IB. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the black limestone member of the Kunga Group 61 Table IC. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Sandilands Formation 65 Table ID. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Ghost Creek Formation 67 Table IE. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Rennell Junction Formation 68 Table IF. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2. PI, QOM, HI. Ol). Values represent means calculated across each outcrop section for the Fannin Formation 9 Table 1G. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Whiteaves Formation 70 Table 1H. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Phantom Creek Formation 71 Table II. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Graham Island Formation 72 Table 1J. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Richardson Bay Formation 73 Table IK. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Robber Point Formation 74 Table IL. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Newcombe Formation 5 Table 1M. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Alliford Formation 76 Table IN. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Longarm Formation 7 Table IO. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent mean calculated across each outcrop section for the Haida Formation 78 Table IP. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Skidegate Formation 9 Table 1Q. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, Ol). Values represent means calculated across each outcrop section for the Honna Formation 80 xvii Table 1R. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Skonun Formation 81 Table 2. Depth to the top and base of the oil window, and thickness of eroded strata data calculated from maturation curves for 12 well and outcrop sections. Depth the top and base of the oil window are extrapolated assuming that the oil window is between 0.50 %Rorand and 1.35 %Rorand. Thickness of eroded strata assumes a zero maturation level of 0.15 %Rorand 88 Table 3. Comparison between paleogeothermal gradients predicted by the modified Arrhenius and Lopatin models utilizing constant and variable geothermal gradients (see text) 125 Table 4. Comparison between timing for entering and exiting the oil window predicted by the modified Arrhenius and Lopatin models utilizing constant and variable geothermal gradients (see text) 140 Table 5. Geochemical parameters from Rock-Eval pyrolysis utilized for interpreting organic maturation, hydrocarbon potential, and type of generated hydrocarbons (modified from Peters, 1986) 212 Table 6A. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the grey limestone member of the Kunga Group 213 Table 6B. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the black limestone member of the Kunga Group 215 Table 6C. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Sandilands Formation 219 Table 6D. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Ghost Creek Formation 221 Table 6E. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Rennell Junction Formation 222 Table 6F. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Fannin Formation 223 Table 6G. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Whiteaves Formation 224 Table 6H. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Phantom Creek Formation 225 Table 61. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Graham Island Formation 226 Table 6J. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Richardson Bay Formation 227 Table 6K. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Robber Point Formation 228 Table 6L. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Newcombe Formation 229 xviii Table 6M. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Alliford Formation 230 Table 6N. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Longarm Formation 231 Table 60. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent mean calculated across each outcrop section for the Haida Formation 232 Table 6P. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Skidegate Formation 233 Table 6Q. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Honna Formation 234 Table 6R. Organic maturation (%Rorand) and Rock-Eval data (TOC, SI, S2, PI, QOM, HI, OI). Values represent means calculated across each outcrop section for the Skonun Formation 235 xix ACKNOWLEDGEMENT The author is grateful to the thesis supervisor, Dr. R.M. Bustin, for his apt supervision and patience. The author also acknowledges the financial support provided by Energy, Mines, and Resources Canada, NSERC grant (A7337) to R.M. Bustin, Chevron Resources Ltd., and Amoco Canada. Special thanks are also due to B.E.B. Cameron, M. Orchard, and C. Hickson for access to their extensive sample collections. The assistance of the U.B.C. Geology Department Technicians is gratefully appreciated. xx 1 INTRODUCTION Evaluation of the petroleum potential of frontier sedimentary basins is an important part of hydrocarbon exploration and requires knowledge concerning the distribution, quality, and level of organic maturation of potential source and reservoir strata. Factors controlling hydrocarbon source potential include the quality, quantity, and degree of organic maturation (DOM) of the organic matter. The level of organic maturation of the strata is influenced primarily by temperature and time (Dow, 1977; Waples, 1980). In the Queen Charlotte Islands, Bustin and Macauley (1988) have identified Lower Jurassic potential source rocks and oil seeps from outcrop sections and exploration wells. The source rock quality and DOM of the Mesozoic and Tertiary sedimentary succession of the Queen Charlotte Islands and adjacent offshore basins, however, have received only limited study. The following study is divided into two parts. In the first part, the DOM of the Mesozoic and Tertiary strata is documented and modelled in order to establish thermal histories of the strata and to predict the timing of hydrocarbon generation. In the second part, the abundance and type of organic matter within the strata are investigated in order to establish the petroleum source rock quality. REGIONAL GEOLOGY OF THE QUEEN CHARLOTTE ISLANDS The Queen Charlotte Islands consist of two main islands, Graham Island to the north and Moresby Island to the south, along with numerous small islands between 51° N, 131° W, and 54° N, 134° W (Figure 1). Sutherland Brown (1968) published the first comprehensive geologic study of the Queen Charlotte Islands; included in this report were regional geologic maps (1:125 000) and stratigraphic, structural, and economic assessments of the exposed and subsurface lithologjc units. The Queen Charlotte Islands are part of the Wrangellia tectonostratigraphic terrane and share a similar Late Paleozoic (?), Triassic, and Jurassic tectonic and stratigraphic history with Vancouver Island and parts of southern Alaska (Figure 2). The Queen Charlotte Islands include a diverse sequence of 2 Figure 1. Location map of British Columbia showing the Queen Charlotte Islands study area 3 1 T 1 H i A ALEXANDER BR BRIDGE RIVER CC CACHE CREEK C CASCADE CD CADWALLADER CR CRESCENT H HOZAMEEN M METHOW MN MONASHEE NA NORTH AMERICA N NOOKSACK PR PACIFIC RIM S STIKINE T TYAUGHTON Y YUKON W WRANGELL - _^KON\ ^ DIST. OF MACKENZIE^ I ALBERTA O Figure 2. Tectonostratigraphic terrane map of western Canada (Armstrong, 1988) 4 sedimentary, volcanic, and plutonic rocks which range in age from Triassic to Recent. The plutonic rocks are predominantly exposed on Moresby Island and the western part of Graham Island; the volcanic and sedimentary rocks crop out in most areas of the Queen Charlotte Islands and underlie Hecate Strait. The following tectonic history and stratigraphic summary are based mainly on the work of Sutherland Brown (1968), Cameron and Tipper (1985), and Cameron and Hamilton (1988). Stratigraphy Strata of the Queen Charlotte Islands range in age from Late Triassic to Recent. The succession is dominated by volcanic rocks with interbedded marine and terrigenous strata (Figure 3). Triassic through Jurassic deposition was nearly continuous and the strata can be correlated with Wrangellian equivalents on Vancouver Island and southern Alaska. The Cretaceous and Tertiary strata, however are unique to the Queen Charlotte Islands and cannot be correlated with strata of equivalent age on Vancouver Island or southern Alaska. The Mesozoic and Tertiary stratigraphy of the Queen Charlotte Islands are summarized below. KARMUTSEN FORMATION The oldest lithologic unit exposed on the Queen Charlotte Islands is the Triassic Karmutsen Formation. The strata consist of more than 4 000 m of tholeiitic lavas comprising chloritized greenstone, amygdaloidal basalt, pillow lava and breccia, aquagene tuff, and minor limestone intercalations (Sutherland Brown, 1968). The Karmutsen Formation also outcrops on Vancouver Island and Bonilla Island (east side of Hecate Strait) and has been correlated with the Nicolai Greenstone of the Wrangell Mountains of southern Alaska (Muller, 1977; Jones et al, 1977; Woodsworth, 1988). The Karmutsen lavas have been interpreted by various authors as oceanic crust originating from an QUATERNARY PLIOCENE u-r — IGENE U ~ M MinppMP -10-O LU Z L 20-AR\ OLIGOCENE U 30-r-rr LU L TEF PALAEOGEI U EOCENE L 40-50-PALEOCENE -MAASTRICHTIAN -PPER CAMPANIAN SANTONIANy -T CONIACIAN TURONIAN -US CENOMANIAN ETACEO ALBIAN 100-CR CC LU APTIAN 3 o BARREMIAN _1 HAUTERIVIAN VALANGINIAN BERRIASIAN -TITHONIAN/ UPPER UPPER VOLGI AN LOWER UPPER KIMMERIDGIAN UPPER OXFORDIAN -O IDLE CALLOVIAN JRASS IDLE BATHONIAN JRASS LJ s BAJOCIAN -AALENIAN CC LU 5 TOARCIAN -PLIENSBACHIAN o _i SINEMURIAN 200-HETTANGIAN 1 TRIASSIC 1 UPPER NORIAN _ 1 TRIASSIC 1 CARNIAN ESTIMATED AGE (MA) MAXIMUM UNCONJOUDATED^TH|CKNESS -57.8 -66.4 -74.5 -84 .87.5 88.5 -91 •113 -119 LONGARM SHALLOW { 8ATHYAL RENNEL.JCT GHOST CR.-^ SANDILANDS UNNAMED BLACK LIMESTONE MEMBER UNNAMED GRAY LIMESTONE MEMBER KARMUTSEN -*-2000+m 6000+m 400m 2800m •»- 1300m — 1220m Moresby Gp. r Alliford 60m -J Newcombe 45m |_Robber Pt.90m *- 285m Graham Is. •*- 840m Richardson Bay —- 30m 85m 64m •*— 50m 68m 500+m *- 274m — 183m 4000+m Figure 3. Stratigraphic column of Mesozoic and Tertiary strata for the Queen Charlotte Islands (modified from Cameron and Hamilton, 1988) 6 oceanic ridge, island arc, or marginal-interarc basin which was erupted subaqueously over a broad, low relief surface (Sutherland Brown, 1968; Monger et al., 1972; Muller et al., 1974; Souther, 1977). The age of the Karmutsen Formation has not been positively determined. The top of the Formation is overlain conformably by Upper Carnian limestones of the Kunga Group. The base of the Karmutsen Formation is not known on the Queen Charlotte Islands but is probably Early or Middle Triassic, similar to the Karmutsen Formation on Vancouver Island (Sutherland Brown, 1968). Some crinoidal limestone found near the base of the Karmutsen in Hutton Inlet may be as old as Permian (Sutherland Brown, 1968). KUNGA GROUP The Kunga Group conformably overlies the Karmutsen Formation and consists primarily of limestone and argillite with some siltstone and sandstone. The strata range in age from Late Carnian to Late Sinemurian (Sutherland Brown, 1968). The Kunga Group was deposited on a stable carbonate platform remote from volcanic sources during a period of initial volcanic quiescence during the Late Triassic followed by arc related volcanism in the Sinemurian (Late Carnian and Norian) (Sutherland Brown, 1968; Cameron and Tipper, 1985). The Kunga Group has been divided by Cameron and Tipper (1985) into the Sandilands Formation and two informal members, a grey limestone member and a black limestone member. Grey Limestone Member The Upper Carnian grey limestone member consists of massive, crystalline, limestone with poorly preserved corals, pelecypods, gastropods, and ammonites (Sutherland Brown, 1968). Grainstone interbeds or lenses and silicified burrows are common near the top of the unit. The grey limestone was deposited on a stable carbonate shelf isolated from clastic and volcanic sediments (Sutherland Brown, 1968). 7 Middle Limestone Member The Lower to Upper Norian middle limestone member consists of thinly bedded, pyritic, flaggy, black, bituminous limestone with cross-bedded calcarenite and minor argillite, limestone conglomerate, and sandstone (Sutherland Brown, 1968). The beds are finely laminated with abundant Halobia and Monotis and may contain concretionary horizons. The middle limestone member was deposited in a partly euxinic o basin with some clastic input but remote from volcanic tuffaceous sources (Sutherland Brown, 1968). Sandilands Formation The Hettangian (?) to Sinemurian Sandilands Formation conformably overlies the middle limestone member and consists of thinly bedded siliceous siltstone and sandstone (or argillite) with interbedded ash-fall tuff, grey-green shale, and thin black shale laminations (Cameron and Tipper, 1985). Thin, interbedded limestone lenses and sedimentary structures (cross-bedding, bioturbation) are rare (Sutherland Brown, 1968). Fauna consist mainly of pelagic pelecypods and ammonites with few foraminifers. Thin, continuous bedding with regular tuffaceous interbeds and abundant pyrite suggest deposition in a relatively deep, partly euxinic basin which received ash-fall tuffs from remote volcanic sources (Cameron and Tipper, 1985). MAUDE GROUP The Pliensbachian-Aalenian Maude Group consists of fossiliferous argillite, shale, calcareous shale, Iithic sandstone, and minor limestone lenses. The Maude Group, where present, conformably and gradationally overlies the Kunga Group (Sutherland Brown, 1968). Cameron and Tipper (1985) have divided the Maude Group into five formations which from base to top are: Ghost Creek, Rennell Junction, Fannin, Whiteaves, and Phantom Creek Formations. 8 Ghost Creek Formation The Lower Pliensbachian Ghost Creek Formation consists of pyritic, bituminous, fetid, dark grey shale with minor silty shale and limestone lenses (Cameron and Tipper, 1985). The Ghost Creek Formation conformably overlies the Sandilands Formation (Kunga Group) from which it is distinguished by the paucity of ash-fall tuff and by a higher proportion of shale in the Ghost Creek Formation (Cameron and Tipper, 1985). Deposition of the Ghost Creek Formation occurred in a deep, partly euxinic basin which was characterized by an abundant pelagic fauna (ammonites, belemnites) and few benthic fauna. Rare ash-fall tuff interbeds suggest decreased volcanism from the Sinemurian to the Early Pliensbachian (Cameron and Tipper, 1985). Rennell Junction Formation The Lower Pliensbachian Rennell Junction Formation consists of fine grained, flaggy sandstone, argillaceous siltstone, grey shale, and minor limestone lenses (Cameron and Tipper, 1985). The shale at the base is glauconitic and grades into siltstone and sandstone near the top. The Rennell Junction Formation conformably overlies the Ghost Creek Formation and contains more siltstone and less bituminous grey shale than the Ghost Creek Formation (Cameron and Tipper, 1985). Biostratigraphic studies suggest that the Rennell Junction Formation represented the progressive infilling of a deep marine basin (Cameron and Tipper, 1985). Fannin Formation The Upper Pliensbachian-Lower Toarcian Fannin Formation is a heterogeneous sedimentary succession of tuffaceous and calcareous sandstone with minor siltstone and rare shale (Cameron and Tipper, 1985). In the upper part of the Fannin Formation, abundant chamosite ooliths occur in an argillaceous matrix (Cameron and Tipper, 1985). The formation was deposited in a shallow, high energy environment at 9 the peak of a regressive cycle (Cameron and Tipper, 1985). Cameron and Tipper (1985) suggest that chamosite ooliths reflect deposition near a warm, humid landmass. Whiteaves Formation The Middle Toarcian Whiteaves Formation consists of carbonaceous, silty shale with minor interbedded argillaceous sandstone and nodular limestone (Cameron and Tipper, 1985). The Whiteaves Formation unconformably overlies the Fannin Formation which is marked by an abrupt lithologic change from sandstone to shale (Cameron and Tipper, 1985). The base of the Whiteaves Formation contains abundant glauconite and septarian nodules. In the upper half of the unit, glauconite is less abundant and septarian nodules are rare (Cameron and Tipper, 1985). According to biostratigraphic studies, the Whiteaves Formation was deposited following a regression (marked by the erosional hiatus at the top of the Fannin Formation) by rapidly transgressing seas (Cameron and Tipper, 1985). Phantom Creek Formation The Upper Toarcian Phantom Creek Formation consists of partly calcareous and argillaceous fine-to coarse-grained sandstone (Cameron and Tipper, 1985). The sandstone is fossiliferous with abundant ammonites, bivalves, and belemnites. The Phantom Creek Formation paraconformably overlies the Whiteaves Formation (Cameron and Tipper, 1985). The lower part of the Phantom Creek Formation was deposited at the peak of a regression which began towards the end of Whiteaves Formation deposition (Cameron and Tipper, 1985). The upper part of the Phantom Creek Formation represents sedimentation during a transgression with very little tuffaceous ash-fall (Cameron and Tipper, 1985). YAKOUN GROUP Diverse strata of the Lower Bajocian Yakoun Group reflects greatly increased volcanic activity as a result of amalgamation between the Wrangellia and Alexander terranes (Cameron and Tipper, 1985). The 10 degree of volcanic input in the strata varies with the proximity to volcanic sources (Cameron and Tipper, 1985). The Yakoun Group is divided into the Graham Island and Richardson Bay Formations (Cameron and Tipper, 1985). Graham Island Formation The Lower Bajocian Graham Island Formation is a heterogeneous unit composed of shale, tuff, and volcanic sandstone. The formation comprises a wide range of lithologies which reflect varying proximity to volcanic sources (Cameron and Tipper, 1985). The Graham Island Formation in central Graham Island is divided into two members, the shale tuff and mottled siltstone member. In Skidegate Inlet, the lithologies of the Graham Island Formation are different than in central Graham Island, but they are in part coeval. The formation in Skidegate Inlet is divided informally into the volcanic sandstone and lapilli members (Cameron and Tipper, 1985). The shale tuff and mottled siltstone members consist of well-bedded bituminous shale, argillaceous and tuffaceous siltstone with minor cross-bedded sandstone (Cameron and Tipper, 1985). The volcanic sandstone and lapilli tuff members consist of lapilli tuff and andesitic agglomerate in the Skidegate Inlet area and sandstone with minor siltstone in the central Graham Island area (Cameron and Tipper, 1985). The shale tuff and mottled siltstone members were deposited in a partly euxinic, deep marine environment whereas the volcanic sandstone and lapilli members were deposited in a shallow marine or possibly non-marine environment (Cameron and Tipper, 1985). 11 Richardson Bay Formation The Lower Bajocian Richardson Bay Formation is a widespread and thick succession of volcanic rocks. The thickness of the formation varies greatly (180 m to 760 m) depending on proximity to the volcanic source (Cameron and Tipper, 1985). The formation is divided into two informal members, the volcanic breccia member and the dark sandstone member (Cameron and Tipper, 1985). The volcanic breccia member consists of massive, poorly sorted porphyritic andesite breccia and tuff, whereas the dark sandstone member consists of carbonaceous sandstone, siltstone, and shale with abundant bivalves, plant debris, and coalified wood (Cameron and Tipper, 1985). The sediments grade laterally into volcanic detritus or volcanic breccia (Cameron and Tipper, 1985). MORESBY GROUP The Upper Bathonian to Lower Callovian Moresby Group contains conglomerate, sandstone, siltstone, and shale which unconformably overlie the Yakoun Group (Cameron and Tipper, 1985). The Moresby Group was deposited on an irregular basin surface after the cessation of Yakoun volcanism and partial erosion of Yakoun and older sediments (Cameron and Tipper, 1985). The sediments were deposited in a relatively shallow basin which supported abundant pelecypods and some ammonites (Cameron and Tipper, 1985). The Moresby Group has been divided into three formations by Cameron and Tipper (1985) which from base to top are: Robber Point, Newcombe, and Alliford. Robber Point Formation The lithology of the Upper Bathonian Robber Point Formation varies from siltstone, tuffaceous siltstone, to volcanic breccia. The sediments contain abundant pelecypods, gastropods, ostracods, and foraminifers (Cameron and Tipper, 1985). 12 Newcombe Formation The Upper Bathonian to Lower Callovian Newcombe Formation consists of well-bedded sandstone at the base grading into massive concretionary, volcaniclastic sandstone at the top. Some concretions contain pelecypods and rare belemnites or ammonites (Cameron and Tipper, 1985). Alliford Formation The Lower Callovian Alliford Formation consist of laminated siltstone with a fauna comprising pelecypods, ammonites, rare belemnites, ostracods, and foraminifers (Cameron and Tipper, 1985). LONGARM FORMATION The Upper Valanginian to Barremian Longarm Formation consists of calcareous siltstone, lithic greywacke, volcaniclastic sandstone, and pebble conglomerate with large Inoceramus shell fragments. Minor volcanic tuff and agglomerate occur at scattered localities (Sutherland Brown, 1968). The siltstone and greywacke of the Longarm Formation were deposited in a relatively deep water environment near the present Rennell Sound fold zone; and the sandstone and conglomerate were deposited in a shoreline environment (Sutherland Brown, 1968). QUEEN CHARLOTTE GROUP The Albian to Conacian Queen Charlotte Group is a thick succession (1 500 m to 2 000 m) of clastic sedimentary rocks which unconformably overlies the Longarm and older formations (Sutherland Brown, 1968; Haggart, 1987). Cameron and Hamilton (1988) divide the Queen Charlotte Group into the Haida, Skidegate, and Honna Formations (Cameron and Hamilton, 1988). 13 Haida Formation The basal unit of the Queen Charlotte Group is composed of granular conglomerate, sandstone, siltstone, and silty shale (Sutherland Brown, 1968; Haggart, 1987). Fogarassy and Barnes (1988) have informally divided the Haida Formation into the basal Haida lithofacies, the lower Haida sandstone lithofacies, and the transitional Haida lithofacies. The basal lithofacies consists of granular conglomerate with interbedded pebbly sandstone, whereas the lower sandstone lithofacies consists of fine to medium grained carbonaceous sandstone, and the transitional lithofacies is composed of interbedded sandstone, siltstone, and silty shale (Fogarassy and Barnes, 1988). Skidegate Formation The Cenomanian to Turonian Skidegate Formation is composed of sandstone, siltstone, and shale (Haggart, 1987; Fogarassy and Barnes, 1988). The Skidegate Formation is divided into two informal units: the Skidegate shale lithofacies which consists of concretionary, silty shale; and the Skidegate sandstone-siltstone lithofacies which consists of thinly bedded, fine grained sandstone, siltstone, and shale (Fogarassy, pers. comm. 1988). Honna Formation The Conacian Honna Formation is composed of sandstone, siltstone, shale, and conglomerate (Haggart, 1987; Fogarassy and Barnes, 1988). The Honna Formation is divided into the basal Honna lithofacies, the middle Honna lithofacies, and the upper Honna lithofacies by Fogarassy and Barnes (1988). The basal lithofacies consists of clast supported pebble and cobble conglomerate with lenticular sandstone. The middle lithofacies consists of sandstone, siltstone, and shale with interbedded conglomerate and massive sandstone whereas the upper lithofacies consists of clast supported pebble and cobble conglomerate with interbedded, lenticular sandstone (Fogarassy and Barnes, 1988). 14 Sutherland Brown (1968) suggests the Queen Charlotte Group was deposited in a marine, near shore environment with considerable submarine topography and an abundant supply of terrestrial organic detritus (Haida Formation). Much of the sediment were sourced from Yakoun volcanics and granitic plutons (Sutherland Brown, 1968). The Skidegate Formation was deposited in a deeper, near shore marine environment during a short transgressive episode. The Queen Charlotte Group was capped by the marine Honna Formation during a period of rapid uplift (Sutherland Brown, 1968). MASSET FORMATION The Oligocene to Miocene Masset Formation consists of mixed mafic and felsic volcanic flows with thin interflow breccias and rare diamictite channel deposits containing carbonized wood (Hickson, 1988). The felsic volcanics are predominantly welded lapilli tuffs (Hickson, 1988). Hamilton (1985) described the flows as subalkaline tholeiites, basaltic andesites, dacites, and rhyolites. The climax of Masset volcanism occurred 20 to 25 Ma, during the Late Oligocene to Early Miocene (Hickson, 1988). Hickson (1988) and Souther (1988) suggest that the areal extent of the Masset volcanics probably closely resembles the current outcrop distribution and did not extend appreciably under Hecate Strait. SKONUN FORMATION The Miocene to Pliocene Skonun Formation consists of a thick succession (1 800 m onshore and >3 000 m offshore) of alternating marine and non-marine sandstone, siltstone, and shale with some lignite, and coal (Sutherland Brown, 1968). Rare conglomerates occur at the base of the Skonun Formation at the Tow Hill well on northern Graham Island (Sutherland Brown, 1968). The Skonun Formation sediments are generally unconsolidated to poorly consolidated and are chemically and mechanically immature (Sutherland Brown, 1968). 15 The Skonun Formation was deposited in alternating marine (near shore) and non-marine (fluvial, deltaic) environments. Galloway (1974) suggests that Skonun Formation deposition post-dated the intrusion of the Coast Plutonic Complex and that the sediments, in part, were sourced from the unroofing of the plutons. Tectonic History The Karmutsen Formation and the Kunga, Maude, Yakoun, and Moresby Groups can be correlated with similar lithologic and stratigraphic units of Wrangellian affinities found on Vancouver Island and southern Alaska (Figure 2) (Sutherland Brown, 1968; Jones et al., 1977; Coney et al., 1980; Cameron and Tipper, 1985). Paleomagnetic data (Yole and Irving, 1980) from the Karmutsen volcanics suggest that Vancouver Island was located approximately 45° (+. 15°), or 3 000 km, south of its current position during Karmutsen volcanism in the Triassic. Similar paleomagnetic results from the Late Triassic Nicolai basalts of southern Alaska indicate 30° of northward displacement of Wrangellian terranes (Hillhouse, 1977). During the Sinemurian, a northwest trending volcanic arc developed offshore of the North American craton which lead to the deposition of interbedded ash-fall tuffs and shales of the Sandilands and Ghost Creek Formations in Early Jurassic shale basins (Cameron and Tipper, 1985). Following the Aalenian, regional uplift (corresponding to rifting between Gondwanaland and Laurasia) resulted in partial erosion of Lower Jurassic Maude Group sediments as represented by a regional unconformity at the top of the Maude Group (Cameron and Hamilton, 1988). During the early Bajocian, the Yakoun Group volcanics erupted accompanying the amalgamation of Wrangellia and Alexander terranes. Yakoun volcanics may have been sourced from partial melting of Karmutsen volcanics and Upper Paleozoic sediments as a result of high heat flow related to subduction and terrane amalgamation (Sutherland Brown, 1968; Monger et al., 1972; Cameron and Hamilton, 1988). Four plutonic suites (Figure 4) occur primarily on Moresby Island and on Graham Island (first studied in detail by Sutherland Brown, 1968, and later by Anderson, 1988). The Middle to Late Jurassic San Christoval and Burnaby Island Plutonic Suites are, in part coeval with, and successor to, the Yakoun Group volcanics (Cameron and Tipper, 1985). Skarn alteration (magnetite, chalcopyrite) and dense calcite veining associated with hydrothermal solutions are prevalent in the Burnaby Island Plutonic Suite. The emplacement of the plutonic suites was coeval with the Nevadan Orogeny (Anderson, 1988; Cameron and Hamilton, 1988). The Oligocene Kano and Carpenter Bay Plutonic Suites are possibly related to Masset Volcanism (Anderson, pers. comm., 1988). During the Early Cretaceous (Valanginian-Aptian), the Longarm Formation was deposited while Wrangellia moved northward with the Farallon plate. Superterrane II (Quesnellia and Stikinia) accreted onto the North American craton during this time period (Cameron and Hamilton, 1988). Following Aptian time, the Queen Charlotte Islands were in a fore-arc position and the Farallon plate began oblique subduction beneath the North American craton (Cameron and Hamilton, 1988). The Conacian Honna Formation sediments are considered to mark the amalgamation of the Wrangellia-Alexander terrane with the Taku terrane as well as the initiation of Kula-Farallon spreading (Cameron and Hamilton, 1988). During Conacian time, the Queen Charlotte Islands were at a latitude approximate opposite southern California (Irving et al., 1985). Northward movement of the Wrangellia-Alexander-Taku superterrane continued until its final accretion to North America during the Tertiary. Accretion of the Wrangellia-Alexander-Taku superterrane with North America is marked by a regional unconformity at the base of the Tertiary Masset volcanic succession (Cameron and Hamilton, 1988). Deposition of the Skonun Formation occurred syn- and post-Masset volcanism during the Miocene and Pliocene. Figure 4. Regional map of the Queen Charlotte Islands showing four plutonic suites (modified from Anderson, 1988): a) Middle to Late Jurassic San Christoval Plutonic Suite (SCPS); b) Oligocene Carpenter Bay Plutonic Suite (CBPS); c) Middle to Late Jurassic Burnaby Island Plutonic Suite (BIPS); d) Oligocene Kano Plutonic Suite 18 REFERENCES Anderson, R.G. 1988 Jurassic and Cretaceous-Tertiary plutonic rocks on the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 213-216. Armstrong, R.L. 1988 Mesozoic and Early Cenozoic magmatic evolution of the Canadian Cordillera: Special Paper 218, Geological Society of America, p. 55-91 Cameron, B.E.B. 1987 Significance of Lower Jurassic hydrocarbon source rocks in the Cumshewa Inlet area, Queen Charlotte Islands, British Columbia; in Current Research, Part A, Geological Survey of Canada, Paper 87-IA, p. 925-928. Cameron, B.E.B. and Tipper, H.W. 1985 Jurassic stratigraphy of the Queen Charlotte Islands, British Columbia; Geological Survey of Canada, Bulletin, v. 365,49 p. Cameron, B.E.B. and Hamilton, T.S. 1988 Contributions to the stratigraphy and tectonics of the Queen Charlotte Basin, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 221-227. Coney, PJ., Jones, D.L., and Monger, J.W.H. 1980 Cordilleran suspect terranes; Nature, v. 288, p. 329-333. Fogarassy, JJLS. and Barnes, W.C. 1988 Stratigraphy, diagenesis and petroleum reservoir potential of the mid- to Upper Cretaceous Haida and Honna formations of the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 265-268. Galloway, W.E. 1974 Deposition and diagenetic alteration of sandstone in northeast Pacific arc-related basins: implications for greywacke genesis; Geological Society of America Bulletin, v. 85, p. 379-390. Haggart, J.W. 1987 On the age of the Queen Charlotte Group of British Columbia; Canadian Journal of Earth Sciences, v. 24, p. 2470-2476. Hamilton, T. 1985 Volcanics of the Cenozoic Masset Formation: implications for geological and tectonic evolution of the Queen Charlotte Islands, British Columbia, Canada; Geological Society of America, Cordilleran Section Annual Meeting, Program with Abstracts, Vancouver, British Columbia, May 8-10, p. 359 Hickson, C J. 1988 Structure and stratigraphy of the Masset Formation, Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-IE, p. 269-274. Hillhouse, J.W. 1977 Paleomagnetism of the Triassic Nicolai Greenstone, McCarthy Quadrangle, Alaska; Canadian Journal of Earth Sciences, 14, p. 2578-2592. 19 Irving, E., Woodsworth,GJ., Wynne, PJ., and Morrison, A, 1985 Paleomagnetic evidence for displacement from the south of the Coast Plutonic Complex, British Columbia; Canadian Journal of Earth Sciences, 22, p. 584-598. Jones, D.L., Silberling, N J., and Hillhouse, J. 1977 Wrangellia-A displaced terrane in northwestern North America; Canadian Journal of Earth Sciences, 14, p. 2565-2577. Martin, HA. and Rouse, G.E. 1966 palynology of Late Tertiary sediments from the Queen Charlotte Islands, British Columbia; Canadian Journal of Botony, 44, p. 171-208. Monger, J.W.H., Souther, J.G., and Gabrielse, H. 1972 Evolution of the Canadian Cordillera: a plate tectonic model; American Journal of Sciences, 272, p. 577-602. Muller, J.E., Northcote, K.E., and Carlisle, D. 1974 Geology and mineral deposits of Alert Bay-Cape Scott map-area, Vancouver Island, British Columbia. Geological Survey of Canada, Paper 74-8. 77 pp. Muller, J.E. 1977 Evolution of the Pacific Margin, Vancouver Island and adjacent areas; Canadian Journal of Earth Sciences, 14, p. 2062-2085. Souther, J.G. 1977 Volcanism and tectonic environments in the Canadian Cordillera-a second look, in Volcanic regimes in Canada, ed. W.RA. Baragar, L.C. Coleman, and M.Hall. Geological Association of Canada, Special Paper 16, p. 3-24. Souther, J.G. 1988 Implications for hydrocarbon exploration of dyke emplacement in the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 241-245. Sutherland Brown, A. 1968 Geology of the Queen Charlotte Islands; British Columbia Department of Mines and Petroleum Resources Bulletin 54, 226 pp. Woodsworth, GJ. 1988 Karmutsen Formation and the east boundary of Wrangellia, Queen Charlotte Basin, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 209-212. Yole and Irving, 1980 Displacement of Vancouver Island: paleomagnetic evidence from the Karmutsen Formation; Canadian Journal of Earth Sciences, 17 p. 1210-1228. 20 PARTI ORGANIC MATURATION OF MESOZOIC AND TERTIARY STRATA OF THE QUEEN CHARLOTTE ISLANDS 21 ABSTRACT The level of organic maturation and the thermal history of Mesozoic and Tertiary strata in the Queen Charlotte Islands have been determined with vitrinite reflectance (%Roro„ .) and numerical modelling (modified Arrhenius and Lopatin models). The degree of organic maturation (DOM) varies from immature to overmature and increases from north to south. The DOM is primarily controlled by high heat flow associated with plutonism on Moresby Island. Upper Triassic-Lower Jurassic Kunga Group strata are immature to overmature (0.45 to 1.75 %R°ranci) on northwest and central Graham Island, and are overmature (2.40 to 5.80 %R°ranci) on Moresby Island south of Cumshewa Inlet. Locally, anomalously high maturation values range up to 3.20 %R°rancj on Graham Island, and 8.31 %R°ranci on Moresby Island adjacent igneous intrusives. Lower Jurassic Maude, Yakoun, and Moresby Groups strata (including Lower Jurassic source rocks) are marginally mature to overmature with maturation increasing from central Graham Island (0.43 %Rorand) to north Moresby Island (1.58 %RoTand). The DOM of Cretaceous strata (Longarm, Haida, Skidegate, and Honna Formations) increases from northwest Graham Island (0.33 to 1.91 %Rorand), to south Graham Island (1.53 to 2.43 %Rorand), to south Moresby Island (2.31 to 4.78 %Rorancj). Tertiary strata are restricted to Graham Island and are generally immature except for the mature succession on western Graham Island (Port Louis well) and northeast Graham Island (basal strata at the Tow Hill well). Calculated thickness of eroded strata on west Graham Island range from 1040 m at Fredrick Island to 735 m at Kennecott Point. Thicknesses of eroded strata are similar for Jurassic sections in central Graham Island at Rennell Junction (1725 m) and north Moresby Island at Cumshewa Inlet (1985 m). Increased thicknesses of eroded strata on north Moresby Island at Onward Point (1500 m) relative to northwest Graham Island at north Lauder Point (745 m) suggests differential uplift for Cretaceous strata at northwest Graham Island. Thicknesses of eroded strata for the Tertiary Skonun Formation range from 375 m on east Graham Island (Tlell well) to 1685 m on west Graham Island (Port Louis well). 22 Constant and variable geothermal gradient thermal regimes were modelled with modified Arrhenius and Lopatin methods. Time-temperature modelling (assuming constant geothermal gradients) predicts high paleogeothermal gradients (45 to 90 °C/km) for up to 180 million years during the Upper Triassic-Tertiary. Variable geothermal gradient modelling (utilizing a 30 °C/km background geothermal gradient) predicts elevated geothermal gradients ranging from 83 to 150 °C/km during Yakoun (between 183 and 178 Ma) and Masset (between 35 and 10 Ma) volcanism. Triassic strata at Fredrick Island are predicted to have entered and exited the oil window during the Early and Late Miocene respectively while strata at Kennecott Point entered the oil window during the Early Miocene and are still in the oil window. Jurassic strata at Rennell Junction and Cumshewa Inlet entered the oil window during the Bajocian and remain within the oil window. Cretaceous strata on north and south Moresby Island entered the oil window during the Early Miocene and are currently within the oil window. The Skonun Formation is generally immature except for strata at west Graham Island (Port Louis well) and northeast Graham Island (Tow Hill well) which entered the oil window in the Late Miocene. 23 INTRODUCTION In the Queen Charlotte Islands, a succession of Mesozoic and Tertiary strata up to 14 000 m thick is exposed. These strata are considered to contain potential source and reservoir rocks (Sutherland Brown, 1968) and during the late 1950's and 1960's, eight offshore and six onshore petroleum exploration wells were drilled to test the Tertiary strata for hydrocarbon accumulations. Recent studies have defined the Mesozoic and Tertiary stratigraphy and examined potential hydrocarbon resources and source rocks for selected strata (Sutherland Brown, 1968; Cameron and Tipper, 1985; Haggart, 1986; Cameron, 1987; Bustin and Macauley, 1988). In this study, the degree of organic maturation (DOM) of Mesozoic and Tertiary strata from the Queen Charlotte Islands is quantified with organic petrology (vitrinite reflectance) in order to document vertical (stratigraphic) and areal trends in organic maturation. The maturation data are modelled to establish areas of potential petroleum generation, the timing of hydrocarbon generation, and to predict the location of the oil window in time and space. The hydrocarbon generative potential of sedimentary strata depends upon the type and abundance of organic matter and the thermal history of the strata (Dow, 1977). The type of organic matter can be determined from geochemical and petrographic analysis (Tissot and Welte, 1984). Organic maturation indices (such as vitrinite reflectance), can be used to infer the time-temperature history of the strata. Maturation data can be used in conjunction with numerical models to predict the timing of hydrocarbon generation, the type of hydrocarbons, the temperatures corresponding to hydrocarbon generation, the fractional conversion of kerogen to liquid hydrocarbons, and other parameters (Tissot and Espitalie, 1975). 24 METHODS Approximately 1700 samples were collected in order to establish lateral and vertical (stratigraphic) variations in organic maturation. One hundred thirty three carbonaceous strata and lignite samples were collected from well cuttings and well core in the Tertiary Skonun Formation from the following six onshore exploration wells: Richfield et al. Cape Ball a-41-1; Richfield Mic Mac Homestead Gold Creek #1; Richfield Mic Mac Homestead Nadu River; Richfield Mic Mac Homestead Tlell #1; Richfield Mic Mac Homestead Tow Hill #1; and Union Port Louis c-28-1. In addition, outcrop samples were collected from the Skonun Formation on Graham Island, lignite samples from Skonun Point and Miller Creek, and carbonaceous siltstone from Log Creek. One hundred and eighty eight lignite and carbonaceous shale outcrop samples were collected from the Cretaceous Longarm, Haida, Skidegate, and Honna Formations. The majority of Cretaceous samples were collected from Graham Island and a few from Moresby Island. Two hundred and forty one limestone, argulite, and carbonaceous sandstone outcrop samples were collected from the Triassic Kunga Group. The majority of Triassic samples were collected from Moresby Island and fewer from Graham and Fredrick Islands. Additional samples together with stratigraphic data were kindly provided by B.E.B Cameron, M. Orchard, and C. Hickson of the Geological Survey of Canada and by T. Fogarassy of the University of British Columbia. Rock-Eval pyrolysis and organic maturation data for Lower Jurassic strata were supplied by R.M. Bustin of the University of British Columbia. The degree of organic maturation (DOM) was determined using the vitrinite reflectance techniques outlined in England and Bustin (1986). Samples containing visible coal or lignite were crushed and analyzed as whole rock samples. Samples containing low concentrations of organic matter were crushed (-80 mesh) and demineralized with hydrochloric and hydrofluoric acids. The samples were mounted in transoptic and 25 heated to 120° C for 5 minutes forming an optically transparent pellet. The pellets were stored in argon or nitrogen gas to prevent oxidation of the organic matter prior to analysis. The mean random vitrinite reflectance (%R°ran(j) m ou (n=1.518 at 546 nm) was measured with the polarizer out using a Leitz R (M.P.V. II) microscope. The mean random vitrinite reflectance was measured rather than the mean maximum vitrinite reflectance (%Rom„v) in order to save time and to enable measurement of smaller particles (Davis, 1978; England and Bustin, 1986). Wherever possible, 50 vitrinite reflectance measurements were made on each sample, and the mean and standard deviation were determined. RESULTS Lateral maturation trends (Figs. 5-20) and vertical maturation profiles (Figs. 21-24) were determined from vitrinite reflectance measurements of samples collected from all regions of the Queen Charlotte Islands (Table 1). The regional DOM increases markedly from Graham Island to south Moresby Island. Regional elevated maturation levels on Moresby and adjacent islands are in part a result of increased heat flow associated with igneous activity (pluton emplacement) in the Middle-Late Jurassic and Oligocene (Anderson, pers. comm., 1988; Anderson, 1988; Souther, 1988). Local, anomalously high maturation values which result from high heat flow near igneous intrusions or possibly from hydrothermal activity near faults have often obscured regional maturation trends. Due to poor outcrop exposure, large scale intrusion by plutonic complexes, and limited lateral continuity of sedimentary units, interpretation of lateral maturation trends is difficult and in some places impossible. The isomaturity maps presented here will thus ultimately require modification as new data is acquired. Most of the organic matter found within the strata is either Type II or Type III (see Part II); therefore, the oil window has been defined as between 0.50 %Roran(i and 1.35 %R°rand f°r tn's study (Dow, 1977). Strata with maturation values less than 0.50 %R°rancj are considered to be immature, and 26 strata with maturation values greater than 1.35 %R°ran(j are considered to be overmature with respect to hydrocarbon generation and preservation. Lateral Variation In Organic Maturity The following section outlines the outcrop exposure and maturation values for selected stratigraphic horizons. Local, high maturation levels which deviate from regional trends are considered anomalous. These anomalous maturation values often overprint regional trends. In the following section, local anomalous maturation values are differentiated from regional trends. KUNGA GROUP In samples collected from Kunga Group lithologies on Moresby Island, vitrinite reflectances were measured from organic matter which was morphologically and texturally indistinguishable from vitrinite. The organic matter did not have definitive form and often occurs as a groundmass. Internal texture varied from homogeneous to mosaic. The Kunga Group is interpreted to be an offshore carbonate platform deposit (see regional geology) with some clastic input suggesting that the organic matter is of marine origin (hydrogen rich) and may not be vitrinite. It is, therefore, possible that the organic matter is either vitrinite, bituminite, or both. Grey Limestone Member The oldest sedimentary unit in the Queen Charlotte Islands is the Late Carnian grey limestone member (informal name from Cameron and Tipper, 1985) of the Kunga Group. The grey limestone member is best exposed on eastern and southern Moresby Island where the strata are overmature (Fig. 5) with regional maturation values ranging from 2.91 %R°rand at Huston Inlet (central Moresby Island) to 5.80 %Roran(j at Breaker Bay (eastern Moresby Island). At Carpenter Bay, maturation values range up to 7.96 %Ro . adjacent to the Carpenter Bay Plutonic Suite (southeastern Moresby Island). Figure 5. Regional surface maturation patterns (%Roranci) °fthe Upper Triassic grey limestone member (Kunga Group). Dashed line represents an inferred contour 28 Black Limestone Member The Late Carnian to Late Norian black limestone member (informal name from Cameron and Tipper, 1985) of the Kunga Group crops out predominantly on central and eastern Moresby Island and is overmature (2.40 to 5.80 %R°ranci)- Tne strata are also exposed locally on northwest Graham Island and in Skidegate Inlet where they are mature to overmature. The regional DOM increases from west to east on Moresby Island (Fig. 6) with maturation values ranging from 2.40 %R°rancj at Huston Inlet (central Moresby Island) to 5.80 %Roran(j at Howay Island (eastern Moresby Island). Local, anomalously high maturation values range up to 8.31 %R°rana at Carpenter Bay. Black limestone member strata are marginally mature to overmature on northwestern Graham Island with maturation values ranging from 0.51 %R°rana at Kennecott Point to 1.59 %Roran^ at Lauder Point. Local, anomalously high maturation values range up to 3.20 %Rorana at Sialun Bay in northwest Graham Island. Sandilands Formation Regional maturation values for the Sinemurian Sandilands Formation, which is exposed primarily on Moresby Island and locally on Graham Island, increase from north to south (Figs. 7 and 10). Values range from 0.45 %Rofan(j at Kennecott Point (northwestern Graham Island) to 3.78 %Roran(j at Kunga Island (central Moresby Island). Locally, values range up to 4.73 %R°ran(j on Moresby Island. Maturation values for central Graham Island and northern Moresby Island range from 0.48 %R°rand m central Graham Island to 1.75 %R°ran(i at Cumshewa Inlet (northern Moresby Island). MAUDE GROUP The regional level of organic maturation for the Maude Group is illustrated in Figure 8. MEAN RANDOM VITRINITE REFLECTANCE (% Rorand> BLACK LIMESTONE MEMBER (KUNGA GROUP) 132° 131° —I L_ Figure 6. Regional surface maturation patterns (%R°rand) of tne Upper Triassic black limestone member (Kunga Group). Dashed line represents an inferred contour. Tick marks on contour indicate decreasing maturation 30 MEAN RANDOM VITRINITE REFLECTANCE (% Rorand) SANDILANDS FORMATION Figure 7. Regional surface maturation patterns (%R°rand) °ftne Sinemurian Sandilands Formation. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation. Maturation gradient is 0.65 log (%Ro rt)/km Figure 8. Regional surface maturation patterns (%R°rand) of the Lower Jurassic Maude Group. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 32 Ghost Creek Formation The Lower Pliensbachian Ghost Creek Formation crops out from central Graham Island to northern Moresby Island where the regional DOM increases from north to south and varies from mature to overmature. Organic maturation values range from 0.50 %Rorana on central Graham Island to 1.53 %Roran(j at Cumshewa Inlet (Figs. 9 and 10). Vitrinite reflectance measurements taken proximal to dikes and sills range up to 1.31 %Roran£j on the central Graham Island to 1.71 %Rorand at Cumshewa Inlet. Similar values were reported by Bustin and Macauley (1988). Rennell Junction Formation The mature to marginally overmature Lower Pliensbachian Rennell Junction Formation is exposed locally on central Graham Island, Skidegate Inlet, and northern Moresby Island. The regional level of organic maturation (Fig. 11) ranges from 0.52 %Roranci on central Graham Island to 1.50 %Roran(i on Maude Island (Skidegate Inlet). Local, anomalously high, maturation values range up to 2.12 %Rofan(j. Fannin Formation Maturation values for the Upper Pliensbachian-Lower Toarcian Fannin Formation (Fig. 12) range from 0.85 %Roran(j at Cumshewa Inlet to 1.58 %Rorancj on Maude Island (Skidegate Inlet). Whiteaves Formation The regional DOM for the Middle Toarcian Whiteaves Formation increases from west to east with maturation values ranging from 0.43 %Rorana on ceniTal Graham Island to 1.51 %Romax on Skidegate Inlet (Fig. 13). Figure 9. Regional surface maturation patterns (%Rorand) °f the Lower Pliensbachian Ghost Creek Formation. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation 34 MEAN RANDOM VITRINITE REFLECTANCE (% Rorand) SANDILANDS & GHOST CREEK FORMATIONS 132° 131° Figure 10. Regional surface maturation patterns (^'Roranc|) °ftne Sinemurian Sandilands and Lower Pliensbachian Ghost Creek Formations. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation. Maturation gradient is 0.65 log (%Ro ri)/km Figure 11. Regional surface maturation patterns (%Rorand) of the Lower Pliensbachian Rennell Junction Formation. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing maturation Figure 12. Regional surface maturation patterns (%R°rand) of the Upper Pliensbachian to Lower Toarcian Fannin Formation. Labelled values do not fit regional trends and are not contoured 37 — 1 132° MEAN RANDOM VITRINITE REFLECTANCE (%Rorand) WHITEAVES FORMATION Figure 13. Regional surface maturation patterns (%Rorand) of the Middle Toarcian Whiteaves Formation. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 38 Phantom Creek Formation The strata outcrop locally and only one organic maturation value (0.46 %R°ran(j) was obtained for the Upper Toarcian Phantom Creek Formation in central Graham Island (Fig. 14). YAKOUN GROUP The regional level of organic maturation for the Yakoun and Moresby Groups is illustrated in Fig. 15. Graham Island Formation The Lower Bajocian Graham Island Formation is marginally mature to mature (Fig. 15) in central Grahamlsland (0.48 %Rorand) and overmature in the Skidegate Inlet area (1.50 %Roranc])-Richardson Bay Formation The Lower Bajocian Richardson Bay Formation is exposed locally in Skidegate Inlet (Fig. 15) where the strata are mature (1.13 %Roranci)-MORESBY GROUP Robber Point, Newcombe and Alliford Formations In Skidegate Inlet, the limited maturation data available indicates that the Upper Bathonian Robber Point (1.10 %Roran(j)>tne Upper Bathonian-Lower Callovian Newcombe (1.08 %Roran(j)> ana tne Lower Callovian Alliford Formations (1.04 %R°ranci) are mature (Fig. 15). Figure 14. Regional surface maturation patterns (%Ro ) of the Middle Toarcian to Aalenian Phantom Creek Formation 40 132° MEAN RANDOM VITRINITE REFLECTANCE (% Roranci) YAKOUN AND MORESBY GROUPS Figure 15. Regional surface maturation patterns (%Ro ) of the Lower Jurassic Yakoun, and Moresby Groups 41 LONGARM FORMATION The Upper Valanginian-Lower Barremian Longarm Formation crops out on Moresby Island and parts of Graham Island. The Longarm Formation is overmature on northern Moresby Island (Fig. 16) with maturation values ranging from 1.53 %Romax to 2.43 %Romax- The strata on eastern Moresby Island are overmature with regional maturation increasing from west (2.31 %Rorand at Huston Inlet) to east (4.86 %Roran(j on Murchison Island). QUEEN CHARLOTTE GROUP Haida Formation The Albian Haida Formation is exposed locally from northwest Graham Island to central Moresby Island. The regional DOM varies from immature to overmature and increases from north to south. Maturation values range from 0.33 %Rorand in Beresford Bay (northwest Graham Island), 1.29 %R°max m Skidegate Inlet, 2.08 %Rorand in Cumshewa Inlet, to 4.18 %Rorand in central Moresby Island (Fig. 17). Local, anomalously high vitrinite reflectance values (up to 1.72 %Roran(j) occur on northwest Graham Island. Skidegate Formation The Cenomanian-Turonian Skidegate Formation crops out in the Skidegate and Cumshewa Inlet areas, northwest Graham Island, and Langara Island. The Skidegate Formation (Fig. 18) is immature to mature on northwest Graham Island (0.40 %R°rand) mature to overmature in Skidegate Inlet (2.21 %Rorand). Regional organic maturation increases from east to west on northwest Graham Island with anomalously high values near Langara Island. A slight increase in the DOM from west to east occurs in both Skidegate and Cumshewa Inlets. Local, anomalously high vitrinite reflectance values range up to 2.55 %Rorand in the Skidegate and Cumshewa Inlet areas. Figure 16. Regional surface maturation patterns (^°^J0Tan^) 01 tne Upper Valanginian to Berremian Longarm Formation. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured 43 MEAN RANDOM VITRINITE REFLECTANCE (% Rorand) HAIDA FORMATION 132° 131° —I I Figure 17. Regional surface maturation patterns (%Ro ^) of the Albian Haida Formation. Values in brackets are minimum and maximum vitrinite reflectances. Maturation gradients are 0.73 and 0.15 log (%Ro .)/km 44 132° MEAN RANDOM VITRINITE REFLECTANCE (% Rorand) SKIDEGATE FORMATION Figure 18. Regional surface maturation patterns (^0^-°ian(j) °fthe Cenomanian to Turonian Skidegate Formation. Values in brackets are minimum and maximum vitrinite reflectances. Maturation gradients are 0.10 and 0.45 log (%Ro ri)/km Figure 19. Regional surface maturation patterns (%Rorand) of the Conacian Honna Formation. Single and numbers in brackets are mean vitrinite reflectance values. Dashed values are minimum and maximum vitrinite reflectance values I— 132° 46 MEAN RANDOM VITRINITE REFLECTANCE (% Rorand) Figure 20. Regional surface maturation patterns (%Roranci) of the Miocene to Pliocene Skonun Formation. Values in brackets are minimum and maximum vitrinite reflectance values. Maturation gradients range from 0.18 to 0.30 log (%Ro H)/km 87-OF-BI : BURNABY ISLAND VITRINITE REFLECTANCE (ERorand) V Si B 87-OF-BJ : BLUE JAY COVE VITRINITE REFLECTANCE (%Rorand) 47 m 87-OF-CB : CARPENTER BAY VITRINITE REFLECTANCE (XRorand) o 87-OF-DP : DELUGE POINT VITRINITE REFLECTANCE (%Rorand) 2 I 40 Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; a) near Moresby Island at Burnaby Island; b) on Moresby Island at Blue Jay Cove; c) on Moresby Island at Carpenter Bay; d) on Moresby Island at Deluge Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation 87-OF-FUN : FUNTER POINT VITRINITE REFLECTANCE (%Rorand) 48 87-OF-HO-A : NORTHEAST POOLE INLET HOWAY ISLAND VITRINITE REFLECTANCE (%Rorand) 87-OF-HO : NORTHEAST POOLE INLET VITRINITE REFLECTANCE (XRorand) o H 87-OF-HP : WEST HOUSTON POINT VITRINITE REFLECTANCE (XRorand) o Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; e) on Moresby Island at Funter Point; f) on Moresby Island in northeast Poole Inlet at Howay Island; g) on Moresby Island in northeast Poole Inlet; h) on Moresby Island at west Huston Inlet. Points are mean vitrinite reflectance values. Error bars are calculated as mean values + standard deviation 87-OF-HU : WEST HUSTON INLET VITRINITE REFLECTANCE (ZRorand) 49 87-OF-HUX-A : EAST HUXLEY ISLAND VITRINITE REFLECTANCE (%Rorand) 87-OF-HUX-B : EAST HUXLEY ISLAND VITRINITE REFLECTANCE (XRorand) 87-OF-HUX-C : NORTHEAST HUXLEY ISLAND VITRINITE REFLECTANCE (%Rorand) Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; i) on Moresby Island at west Huston Inlet; j) near Moresby Island on east Huxley Island; k) near Moresby Island on east Huxley Island 1) near Moresby Island on northeast Huxley Island. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation M 87-OF-JED : WEST JEDWAY POINT VITRINITE REFLECTANCE (%Rorand) 3 I 40 » VITRINITE REFLECTANCE - FAULT / IGNEOUS INTRUSION N 50 87-OF-KT-A : WEST KUNGHIT ISLAND VITRINITE REFLECTANCE (%Rorand) > VITRINITE REFLECTANCE - MIDDLE-LOWER CONTACT 87-OF-KT-B : WEST KUNGHIT ISLAND VITRINITE REFLECTANCE (JSRorand) • VITRINITE REFLECTANCE — VIODLE-LOWER CONTACT 87-OF-KU : NORTHWEST KUNGA ISLAND VITRINITE REFLECTANCE (XRorand) Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; m) on Moresby Island at west Jedway Point; n) near Moresby Island on west Kunghit Island; o) near Moresby Island on west Kunghit Island; p) near Moresby Island at northwest Kunga Island. Points are mean vitrinite reflectance values. Error bars are calculated as mean values + standard deviation 51 87-OF-RI : SOUTHEAST ROSE INLET VITRINITE REFLECTANCE (%Rorand) 87-OF-SC : SOUTH COVE, CARPENTER BAY VITRINITE REFLECTANCE (XRorand) 87-OF-SHU : SOUTHWEST HUSTON INLET VITRINITE REFLECTANCE (%Rorand) 87-OF-SKU-A : SOUTH KUNGA ISLAND VITRINITE REFLECTANCE (XRorand) Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; q) on Moresby Island at southeast Rose Inlet; r) on Moresby Island at South Cove in Carpenter Bay, s) on Moresby Island at southwest Huston Inlet; t) near Moresby Island on south Kunga Island. Points are average vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation Uf 87-OF-SKU-C : SOUTH KUNGA ISLAND VITRINITE REFLECTANCE (JSRorand) | LATE z o > z MIDI KUr MIDI pi > I-n * z o n o TO m > O c CD z u • 87-OF-TB : KUNGHIT ISLAND TREAT BAY VITRINITE REFLECTANCE (JSRorand) w 87-DV-11 KUNGA ISLAND VITRINITE REFLECTANCE (%Rorand) > vrfRiNrrc REFLECTANCE - FAULT — SANDILANDS-UIDDLE CONTACT 87-DV-13 : SIALUN BAY VITRINITE REFLECTANCE (%Rorand) • «rr«iNrrt HEFUCTANCE z: o Figure 21. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Upper Triassic to Sinemurian Kunga Group; u) near Moresby Island on south Kunga Island; v) near Moresby Island at Treat Bay on Kunghit Island; w) near Moresby Island on Kunga Island; x) on northwest Graham Island at Sialun Bay. Points are mean vitrinite reflectance values. Error bars are calculated as mean values + standard deviation BC-SECTION-04 : MAUDE ISLAND VITRINITE REFLECTANCE (%Rorand) B BC-SECTION-05 : MAUDE ISLAND VITRINITE REFLECTANCE (%Rorond) BC-SECTION-06 : MAUDE ISLAND VITRINITE REFLECTANCE (JSRorond) o BC-SECTION-07 : WHITEAVES BAY VITRINITE REFLECTANCE (XRorand) is 31 Figure 22. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Lower Jurassic Maude Group; a) in Skidegate Inlet on Maude Island; b) in Skidegate Inlet on Maude Island; c) in Skidegate Inlet on Maude Island; d) in Skidegate Inlet at Whiteaves Bay. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation 54 BC-SECTION-08 : MAUDE ISLAND VITRINITE REFLECTANCE (XRorond) LATE | TO E | FAf • Si if ii z z — MUDE ! c_ CZ EARLY : GROl 3 -iAS PL "D | GHOST CREEr -SIC lENSBACHIAN | GHOST CREEr -n KUh £ B Ci g IURIAN 1 \ GROUP! z o tyi E BC-SECTION-09 : MAUDE ISLAND VITRINITE REFLECTANCE (%Rorand) o z: BC-SECTION-1 1 : YAKOUN RIVER VITRINITE REFLECTANCE (XRorand) H BC-SECTION-12 : YAKOUN RIVER VITRINITE REFLECTANCE (XRorand) Figure 22. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Lower Jurassic Maude Group; e) in Skidegate Inlet on Maude Island; f) in Skidegate Inlet on Maude Island; g) in central Graham Island on the Yakoun River; h) in central Graham Island on the Yakoun River. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation 55 BC-SECTION- 14 : CENTRAL GRAHAM ISLAND VITRINITE REFLECTANCE (XRorand) 150 2 Q 200 BC-SECTION-15 : YAKOUN RIVER VITRINITE REFLECTANCE (XRorand) K BC-SECTION-16 : ALLIFORD BAY VITRINITE REFLECTANCE (XRorand) R-SQUARE = 0.67 MATURATION GRADIENT = 1.60 %Rorond/km BC-SECTION-17 : ROBBER POINT VITRINITE REFLECTANCE (XRorand) ' VITRINITE REFLECTANCE - UNCONFORMITY R—SQUARE = 0.74 MATURATION GRADIENT = 1.60 XRorand/km Figure 22. Vertical maturation profiles [vitrinite reflectance (%Roran(j)/stratigraphic depth] of the Lower Jurassic Maude, Yakoun, or Moresby Groups; i) in central Graham Island; j) in central Graham Island on the Yakoun River; k) in Skidegate Inlet at Alliford Bay; 1) in Cumshewa Inlet at Robber Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation. Maturation gradient is log (%Rorand)/km 87-DV-14 : SOUTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) VITRINrTC REFLECTANCE - OIKE/SILL B 87-DV-17 : CASWELL POINT VITRINITE REFLECTANCE (XRorand) | REFLECTANCE VALUE - COVERED INTERVAL - SILL 56 87-DV-18 : FLEURIEU POINT VITRINITE REFLECTANCE (XRorand) Figure 23. Vertical maturation profiles [vitrinite reflectance (%Roran(J)/stratigraphic depth] of the Cretaceous Haida Formation;a) on northwest Graham Island at south Lauder Point; b) on northwest Graham Island at Caswell Point; c) on northwest Graham Island at Fleurieu Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation CAA-86-05 : CASWELL POINT VITRINITE REFLECTANCE (XRorand) R—SQUARE = 0.Q9 MATURATION GRADIENT = 1.50 XRorand/km 57 CAA-86-06 : FLEURIEU POINT VITRINITE REFLECTANCE (%Rorand) ^ 150 2 Figure 23. Vertical maturation profiles [vitrinite reflectance (%Roran(J)/stratigraphic depth] of the Cretaceous Haida Formation; d) on northwest Graham Island at Caswell Point; e) on northwest Graham Island at Fleurieu Point. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +_ standard deviation. Maturation gradient is log (%Ro ri)/km CAA-86-3 : SOUTH BERESFORD BAY VITRINITE REFLECTANCE (XRorand) > ANOMALOUS RFLECTANCE VALUE - FRACTURE ZONE B 58 87-DV-16 : NORTH NEWCOMBE HILL VITRINITE REFLECTANCE (XRorand) no SKI r- n n SKI > z o CRETACEOUS fE CENOMANIAN CHARLOTTE Gl EGATE FORMATI fE CENOMANIAN ION OUP ION . VITRINITT REFLECTANCE * ANOMALOUS REFLECTANCE VALUE - MINOR FOLD/FAULT ZONE • SILL R-SQUARE = 0.85 MATURATION GRADIENT = 1.0 XRorand/km 87-DV-20 : HART POINT, LANGARA ISLAND VITRINITE REFLECTANCE (XRorand) 87-DV-21 : COX BAY, LANGARA ISLAND VITRINITE REFLECTANCE (XRorand) Figure 24. Vertical maturation profiles [vitrinite reflectance (%Rorand)/stratigraphic depth] of the Cretaceous Skidegate Formation; a) on northwest Graham Island at south Beresford Bay; b) on northwest Graham Island at north Newcombe Hill; c) on Langara Island at Hart Point; d) on Langara Island at Cox Bay. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation. Maturation gradient is log (%Ro .)/km 59 TABLEIA GREY LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand ™AX TOC sl S2 PI QOM HI 01 OF SECTION BB MEAN # OF SAMPLES 5.8 3. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BI MEAN # OF SAMPLES 0. p. 0. 0. 0. 0. 0. 0. OF SECTION BJ MEAN # OF SAMPLES 2.35 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BR MEAN # OF SAMPLES 2.72 4. 0. 0. 0. 0. 0. 0. 0. OF SECTION CB MEAN # OF SAMPLES 2. 0. 0. 0. 0. 0. OF SECTION CRE MEAN # OF SAMPLES 4.59 1. 0. 0. 0. 0. 0. OF SECTION HP MEAN # OF SAMPLES 2.61 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HU MEAN # OF SAMPLES 2.91 0. 0. 0. 0. 0. 0. OF SECTION JED MEAN # OF SAMPLES 6.56 3. 0. 0. OF SECTION KT MEAN # OF SAMPLES 4.39 10. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION TB MEAN # OF SAMPLES 4.38 4. 0. 0. 0. 0. 0. 0. 0. 0. 60 TABLE IA (CONT.) GREY LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %R°rand ™AX TOC sl S2 PI QOM HI OI OF SECTION TIT MEAN # OF SAMPLES 5.28 1. 0. 0. 0. 0. SECTION 1 MEAN # OF SAMPLES 1.1 0.01 0.03 0.08 3. 3. 3. 3. . 0.02 2. 35. 3. 3. 3. SECTION 3 MEAN # OF SAMPLES 0.18 1. 33. 1. SECTION 6 MEAN # OF SAMPLES 0.06 6. 48. 6. SECTION 7 MEAN # OF SAMPLES 0.28 4. 0. 4. 0.01 4. 26. 4. SECTION 8 MEAN # OF SAMPLES 0.24 4. 0.02 4. 0.08 4. 24. 4. SECTION 9 MEAN # OF SAMPLES 0. 0. 0.06 1. 0. 1. 0. 1. SECTION 10 MEAN # OF SAMPLES 0. 0. 0.06 1. SPOT SAMPLE MEAN # OF SAMPLES * * 0. 0. 0.10 5. 132. 5. TF SPOT SAMPLE MEAN # OF SAMPLES 2.95 3. 0. 61 TABLE IB BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand ™AX TOC sl S2 PI QOM HI Ol OF SECTION Bl MEAN 4.56 * * # OF SAMPLES 28. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BJ MEAN 4.09 * • # OF SAMPLES 10. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CB MEAN 8.31 ........ # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CRE MEAN 4.59 ........ # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION DP MEAN 4.84 ........ # OF SAMPLES 2. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION EPO MEAN 4.81 * * « * * # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION FUN MEAN 5.05 * * # OF SAMPLES 2. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION GB MEAN 3.13 ........ # OF SAMPLES 2. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HO MEAN 5.08 ........ # OF SAMPLES 9. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HP MEAN 2.94 ....... # OF SAMPLES 5. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HUX MEAN 4.33 ........ # OF SAMPLES 19. 0. 0. 0. 0. 0. 0. 0. 0. 62 TABLE IB (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %R°rand ™AX TOC S1 S2 PI Q°M HI OI OF SECTION JED MEAN # OF SAMPLES 4.23 1. 0. 0. 0. 0. 0. 0. 0. OF SECTION KT MEAN # OF SAMPLES 4.66 18. 0. 0. 0. 0. 0. 0. 0. OF SECTION KU MEAN # OF SAMPLES 4.56 12. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION LUX MEAN # OF SAMPLES 4.63 1. 0. 0. 0. 0. 0. 0. 0. OF SECTION NPO MEAN # OF SAMPLES 4.62 3. 0. 0. 0. 0. 0. OF SECTION POO MEAN # OF SAMPLES 3.53 5. 0. 0. 0. 0. 0. OF SECTION RH MEAN # OF SAMPLES 5.6 2. 0. 0. 0. 0. 0. 0. 0. OF SECTION RI MEAN # OF SAMPLES 4.37 6. 0. 0. 0. 0. 0. 0. 0. OF SECTION ROSS MEAN # OF SAMPLES 4.87 2. 0. 0. 0. 0. 0. OF SECTION SC MEAN # OF SAMPLES 4.35 5. 0. 0. 0. 0. 0. 0. OF SECTION SHU MEAN # OF SAMPLES 2.4 6. 0. 0. 0. 0. 0. 0. 63 TABLE IB (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand TMAX TOC SI S2 PI QOM HI Ol OF SECTION SI MEAN # OF SAMPLES OF SECTION SK MEAN # OF SAMPLES 4.1 4. 3.78 3. 0. 0. 0. 0. OF SECTION SKU MEAN # OF SAMPLES OF SECTION SPO MEAN # OF SAMPLES 4.58 13. 3.89 1. 0. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION TB MEAN # OF SAMPLES 2.37 1. 0. 0. OF SECTION VP MEAN # OF SAMPLES SECTION 1 MEAN # OF SAMPLES SECTION 2 MEAN # OF SAMPLES SECTION 3 MEAN # OF SAMPLES 3.85 1. 0. 0. 0.82 0. 8. 8. 0.9 5. 0.01 5. 0. 0. 0.01 0. 32. 8. 8. 0. 0. 0. 231. 5. 5. 5. 5. 1.02 0. 0. 0. 0.01 1. 13. 0. 0. SECTION 4 MEAN # OF SAMPLES 3.64 3. 2.21 4. 0.05 4. 0.03 4. 0.05 4. 16. 4. 13. 4. SECTION 7 MEAN # OF SAMPLES 0.41 3. 0. 3. 64 TABLE IB (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM HI 01 SECTION 8 MEAN * • 0.25 0. 0. 0. 0.02 0. 50. # OF SAMPLES 0. 0. 5. 5. 5. 5. 5. 5. 5. SECTION 9 MEAN • • 0.22 0. 0. 0. 0.01 1. 9. # OF SAMPLES 0. 0. 9. 9. 9. 9. 9. 9. 9. SECTION 10 MEAN 4.29 * 1.16 0. 0.01 0.07 0.01 1. 24. # OF SAMPLES 14. 0. 15. 15. 15. 15. 15. 15. 15. SECTION 11 MEAN 5.11 * 2.56 0.07 0.01 0.87 0.03 0. . 11. # OF SAMPLES 1. 0. 1. 1. 1. 1. 1. 1. 1. SECTION 12 MEAN 0.51 440. 3.6 1.21 14.08 0.08 4.19 385 . 9. # OF SAMPLES 6. 6. 6. 6. 6. 6. 6. 6. 6. SECTION 13 MEAN 3.19 587. 2.9 0.04 0.08 0.33 0.04 2. 24. # OF SAMPLES 16. 1. 18. 18. 18. 18. 18. 18. 18. SECTION 14 MEAN 1.59 ........ # OF SAMPLES 2. 0. 0. 0. 0. 0. 0. 0. 0. SECTION 15 MEAN 1.47 467. 2.69 0.64 0.83 0.44 035 30. 47. # OF SAMPLES 2. 1. 1. 1. 1. 1. 1. 1. 1. SECTION 19 MEAN 1.18 444. 2.17 037 4.69 0.12 2.19 192. 14. # OF SAMPLES 16. 18. 18. 18. 18. 18. 17. 18. 18. SPOT SAMPLE MEAN 4.04 • 1.06 0. 0.01 0.04 0.02 0. 25. # OF SAMPLES 30. 0. 38. 38. 38. 38. 38. 38. 38. 65 TABLE IC SANDILANDS FORMATION SECTION NAME %Ro . TMAX TOC rand SI S2 PI QOM HI OI SECTION 5 MEAN # OF SAMPLES 0.51 4. 0.01 4. 0.03 4. 0.06 4. 0.03 4. 49. 4. SECTION 11 MEAN # OF SAMPLES 3.78 18. 1.53 21. 0.04 21. 0.03 21. 0.59 21. 0.05 21. 2. 21. 9. 21. SECTION 12 MEAN # OF SAMPLES 0.45 436. 18. 10. 2.66 10. 0.77 10. 12.9 10. 0.06 10. 4.66 10. 437. 10. 10. 10. SPOT SAMPLE MEAN # OF SAMPLES 0.59 8. 0.01 8. CENTRAL GRAHAM ISLAND B-QUARRY MEAN # OF SAMPLES 0.40 443. 17. 17. 3.14 17. 1.64 17. 13.85 17. 0.14 17. 4.26 17. 372. 17. 36. 17. CENTRAL GRAHAM ISLAND D-QUARRY MEAN # OF SAMPLES 0.66 447. 4. 4. 1.32 5. 0.67 5. 3.83 5. 0.16 4. 2.73 5. 229. 5. 525. 5. CENTRAL GRAHAM ISLAND BRANCH ROAD 57 MEAN # OF SAMPLES 0.65 437. 6. 6. 1.25 6. 0.47 6. 3.43 6. 0.16 6. 3.32 6. 264. 6. 42. 6. CENTRAL GRAHAM ISLAND MAIN ROAD MEAN # OF SAMPLES 0.60 445. 4. 4. 2.08 5. 1.02 5. 4.9 5. 0.15 5. 1.94 5. 159. 5. 68. 5. CENTRAL GRAHAM ISLAND WELL 1-178 MEAN # OF SAMPLES 0.60 437. 32. 32. 1.75 33. 1.12 33. 3.86 33. 0.25 33. 2.75 33. 210. 33. 48. 33. CENTRAL GRAHAM ISLAND WELL 1-179 MEAN # OF SAMPLES 0.88 447. 40. 37. 9.6 40. 0.50 40. 4.12 40. 0.31 38. 2.71 39. 242. 39. 73. 39. 66 TABLE IC (CONT.) SANDILANDS FORMATION SECTION NAME %Ro . TMAX TOC rand SI S2 PI QOM HI Ol CENTRAL GRAHAM ISLAND WELL 1-278 MEAN # OF SAMPLES 0.65 447. 47. 47. 1.91 47. 0.99 47. 4.60 47. 0.23 47. 236 47. 205. 47. 57. 47. MAUDE ISLAND MEAN # OF SAMPLES 1.35 465. 1.47 9. 0.24 9. 0.52 9. 0.42 9. 0.44 9. 27. 9. 34. 9. RENNELL SOUND MEAN # OF SAMPLES 1.57 479. 32. 32. 1.47 33. 0.15 33. 0.3 33. 0.40 33. 0.32 33. 17. 33. 18. 33. SHIELDS BAY MEAN # OF SAMPLES 1.27 7. 037 7. 0.06 7. 0.0 7. 1.0 7. 0.09 7. 0.0 7. 67 TABLE ID GHOST CREEK FORMATION SECTION NAME %Ro . TMAX TOC rand SI S2 PI QOM HI OI BC SECTION 10 MEAN # OF SAMPLES 0.55 448. 1.66 0.39 5.11 0.08 3.19 218. 13. 3. 4. 4. 4. 4. 4. 4. 4. 4. BC SECTION 4 MEAN # OF SAMPLES 1.32 486. 1. 1. 0.68 1. 0.07 1. 0.25 1. 0.22 1. 0.47 1. 36. 1. 29. 1. BC SECTION 7 MEAN # OF SAMPLES 1.51 470. 2 2 1.63 7 0.43 7 0.63 7 0.41 7 0.65 7 38. 17. BC SECTION 8 MEAN # OF SAMPLES 1.5 480. 4. 4. 1.84 4. 0.44 4. 0.7 4. 0.41 4. 0.66 4. 38. 4. 15. 4. BC SECTION CAA-86-2 MEAN # OF SAMPLES 0.88 454. 6. 4. 1.27 5. 0.43 5. 1.98 5. 0.17 5. 1.73 5. 141. 5. 32. 5. CENTRAL GRAHAM ISLAND A-QUARRY MEAN # OF SAMPLES 0. 50 438. 1. 1. 0.6 1. 1.46 1. 1.76 1. 0.45 1. 5.37 1. 293. 1. 108. 1. MAUDE ISLAND MEAN # OF SAMPLES 1.38 442. 5. 5. 1.90 5. 0.55 5. 4.66 5. 0.10 5. 2.43 5. 209. 5. 105. 5. RENNELL SOUND MEAN # OF SAMPLES 1.57 477. 7. 7. 0.79 7. 0.05 7. 0.09 7. 0.48 7. 0.14 7. 106. 7. CENTRAL GRAHAM ISLAND WELL 1-179 MEAN # OF SAMPLES 0.88 444. 36. 36. 1.73 36. 0.36 36. 6.64 36. 0.07 33. 3.73 34. 349. 34. 76. 34. WHITEAVES BAY MEAN # OF SAMPLES 1.35 448. 6. 6. 1.6 6. 0.46 6. 0.60 6. 0.49 6. 0.62 6. 32. 6. 68 TABLE IE RENNELL JUNCTION FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM HI OI BC SECTION 10 MEAN 032 445. 0.71 0.25 1.27 0.16 2.14 178. 46. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION 4 MEAN 1.17 467. 038 0.05 0.16 0.12 0.33 28. 288. # OF SAMPLES 2. 1. 2. 2. 2. 2. 2. 2. 2. BC SECTION 7 MEAN 1.5 488. 1.57 0.27 0.35 0.44 0.39 22. 8. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION 8 MEAN 1.45 471. 1.96 0.4 039 0.41 0.51 30. 21. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION CAA-86-2 MEAN 0.88 458. 1.07 0.05 0.3 0.14 0.84 93. 78. # OF SAMPLES 3. 4. 4. 4. 4. 4. 4. 4. 4. 69 TABLE IF FANNIN FORMATION SECTION NAME %R°ra„d ™AX TOC SI S2 „ QOM HI OI BC SECTION 4 MEAN # OF SAMPLES BC SECTION 7 MEAN # OF SAMPLES BC SECTION 8 MEAN # OF SAMPLES BC SECTION 8 MEAN # OF SAMPLES BC SECTION CAA-86-2 MEAN # OF SAMPLES NORTH MORESBY MEAN # OF SAMPLES (*Ro ) max' 1.31 2. 0. 1.45 3. 1.47 3. 0. Ul 5. 0.85 2. 1.42 1. 0.18 2. 0.26 3. 0.28 5. 0.01 2. 0.03 3. 0.02 5. 0.01 2. 0.25 0.09 3. 0.08 5. 0.24 3. 0.2 5. 0.13 2. 0.34 5. 8. 74. 0.23 0.02 0.05 0.22 0 31 25 3- 3- 3. 3. 3. 0.53 42. 3. 3. 28. 5. 27. 3. 136. 5. 70 TABLE 1G WHITEAVES FORMATION SECTION NAME %Ro . TMAX TOC SI S2 PI QOM HI Ol rand BC SECTION 10 MEAN # OF SAMPLES 0.64 448. 0.18 0.01 0.10 0.03 0.62 60. 51. 5. 1. 5. 5. 5. 5. 5. 5. 5. BC SECTION 11 MEAN # OF SAMPLES 0.43 440 0.33 0.01 0.18 0.07 0.62 57. 6. 5. 1. 5. 5. 5. 5. 5. 5. 5. BC SECTION 12 MEAN # OF SAMPLES 0.46 442. 2. 1. 5.27 0.02 0.24 0.09 0.43 88. 14. 2. 2. 2. 2. 2. 2. 2. BC SECTION 14 MEAN # OF SAMPLES 0.78 4. 0. 0.26 4. 0.01 4. 0.11 4. 0.11 4. 0.47 4. 42. 4. 10. 4. BC SECTION 15 MEAN # OF SAMPLES 0.63 440. 5. 4. 039 5. 0.04 5. 0.36 5. 0.11 5. 0.65 5. 58. 5. BC SECTION 4 MEAN # OF SAMPLES 1.26 3. 0. 0.23 3. 0.0 3. 0.01 3. 0.17 3. 0.07 3. 5. 3. 125. 3. BC SECTION 5 MEAN # OF SAMPLES 1.5 4. 0.34 3. 0.01 3. 0.05 3. 0.26 3. 0.18 3. 14. 3. BC SECTION 6 MEAN # OF SAMPLES 1.49 3. 0.27 4. 0.0 4. 0.02 4. 0.13 4. 0.08 4. 54. 4. BC SECTION 7 MEAN # OF SAMPLES 1.42 3. 0. 0.32 3. 0.02 3. 0.08 3. 0.2 3. 0.32 3. 25. 3. 18. 3. BC SECTION CAA-86-2 MEAN # OF SAMPLES 0.82 464. 2. 2. 1.80 2. 0.16 2. 1.13 2. 0.13 2. 0.73 2. 64. 2. 16. •y NORTH MORESBY MEAN # OF SAMPLES (*Ro ) v max' 131 1. 71 TABLE1H PHANTOM CREEK FORMATION SECTION NAME %Rorand ™AX TOC sl S2 PI QOM HI 01 BC SECTION 12 MEAN 0.46 440. 035 0.38 1.85 0.16 3.9 322. 10. # OF SAMPLES 4. 4. 4. 4. 4. 4. 4. 4. 4. o 72 TABLE II GRAHAM ISLAND FORMATION SECTION NAME %R°rand T00 S1 S2 PI °-OM HI OI BC SECTION 10 MEAN # OF SAMPLES 0.48 446. 8. 5. 0.96 8. 0.08 8. 137 8. 0.06 1.17 111. 86. BC SECTION 14 MEAN # OF SAMPLES 0.77 443. 6. 4. 0.88 7. 0.14 7. 2.22 7. 0.23 7. 1.94 7. 127. 7. 14. 7. BC SECTION 6 MEAN # OF SAMPLES 1.5 3. 0. 0.34 3. 0.01 3. 0.08 3. 0.08 3. 0.26 3. 24. 3. 43. 3. 73 TABLE 1J RICHARDSON BAY FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI Q°M HI OI BC SECTION 16 MEAN 1.13 396. 1.13 0.20 0.52 0.28 0.63 45. 11. # OF SAMPLES 6. 6. 6. 6. 6. 6. 6. 6. 6. 74 TABLE IK ROBBER POINT FORMATION SECTION NAME %Ro . TMAX TOC SI S2 PI QOM HI OI rand BC SECTION 16 MEAN 1.10 468. 0.78 0.14 0.35 0.29 0.63 44. 15. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. TABLE 1L NEWCOMBE FORMATION SECTION NAME %R°rand ™AX TOC S1 S2 PI QOM BC SECTION 17 MEAN 1.08 ' 0.51 0.02 0.15 0.12 0.34 # OF SAMPLES 3. 0. 3. 3. 3. 3. 3. 76 TABLE1M ALLIFORD FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 P1 QOM HI OI BC SECTION 16 MEAN 1.04 320. 1.10 0.22 0.89 0.20 1.01 80. 13. # OF SAMPLES 3. 3. 3. 3. 3. 3. 3. 3. 3. \ TABLE IN LONGARM FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI QOM SPOT SAMPLE MEAN 3.18 * 0.26 0. 0. 0.03 0.03 # OF SAMPLES 20. 0. 33. 33. 33. 33. 33. NORTH MORESBY MEAN 2.07* ...... # OF SAMPLES 5. (*Ro ) max' 78 TABLEIO HAIDA FORMATION SECTION NAME %Ro . TMAX TOC SI S2 PI QOM HI Ol rand BC SECTION CAA-86-1 MEAN # OF SAMPLES 0.98 701. 26. 17. 0.68 26. 0.05 26. 0.36 26. 0.1 26. 0.56 26. 49. 26. 5. 26. BC SECTION CAA-86-5 MEAN # OF SAMPLES 0.36 439. 10. 10. 0.73 11. 0.01 11. 0.48 11. 0.02 11. 0.67 11. 65. 11. 29. 11. SECTION 14 MEAN # OF SAMPLES 1.51 504. 8. 2. 2.23 3. 0.35 3. 0.74 3. 0.27 3. 0.48 3. 34. 3. 36. 3. SECTION 15 MEAN # OF SAMPLES 0.77 449. 40. 2. 2.49 2. 0.07 2. 0.9 2. 0.43 -> 39. i 50. SECTION 17 MEAN # OF SAMPLES 0.68 11. 0. SECTION 18 MEAN # OF SAMPLES 0.43 14. SPOT SAMPLE MEAN # OF SAMPLES 4.04 3. 0.13 7. 0. 7. 0.14 7. 0.02 7. 0. 7. 33. 7. NORTH MORESBY MEAN # OF SAMPLES (*Ro ) v max' 1.13 2. 79 TABLE IP SKIDEGATE FORMATION SECTION NAME %R°rand ™AX TOC S1 S2 PI °-OM HI OI SECTION 20 MEAN # OF SAMPLES 1.91 497. 14. 1. 0.6 11. 0.01 11. 0.08 11. 0.16 11. 0.24 11. 33. 11. 74. 11. BC SECTION CAA-86-3 MEAN # OF SAMPLES 0.96 433. 35. 11. 0.26 32. 0.03 32. 0.18 32. 0.15 32. 0.95 32. 79. 32. 68. 32. BC SECTION CAA-86^ MEAN # OF SAMPLES 0. 0. 0. 0. 0. 0. 0. 0. BC SECTION CAA-86-6 MEAN # OF SAMPLES 0.4 439. 0.73 0.02 0.54 0.03 0.73 70. 26. 23. 25. 25. 25. 25. 25. 25. 25. 25. BC SECTION CAA-86-T-3 MEAN # OF SAMPLES 1.09 464. 7. 2. 0.17 7. 0.01 7. 0.10 7. 0.07 7. 0.85 6. 65. 7. 146. 7. BC SECTION CAA-86-T^t MEAN # OF SAMPLES 0.47 437. 8. 2. 0.43 5. 0.19 5. 0.32 5. 31. 5. 70. 5. BC SPOT SAMPLE MEAN # OF SAMPLES 1.8 470. 66. 10. 031 53. 0.02 53. 0.18 53. 0.06 53. 0.4 53. 37. 53. 28. 53. SECTION 16 MEAN. # OF SAMPLES 0.71 442. 10. 2. 0.3 0.01 0.19 0.04 0.71 67. 81. SECTION 21 MEAN # OF SAMPLES 1.39 456. 0.32 0.02 0.12 0.11 0.44 36. 14. 11. 1. 10. 10. 10. 10. 10. 10. 10. SECTION 22 MEAN # OF SAMPLES 0.87 436. 3. 1. 0.63 2. 0.17 2. 0.25 7 24. 7 76. 7 SPOT SAMPLE MEAN # OF SAMPLES 2.94 3. 0.13 4. 0.02 4. 0.04 4. 0.31 3. 20. 4. 95. 4. 80 TABLE 1Q HONNA FORMATION SECTION NAME %Ro _, TMAX TOC SI S2 PI QOM HI Ol rand SECTION 22 MEAN # OF SAMPLES 1.14 436. 16. 7. 0.43 12. 0.03 12. 0.24 12. 0.09 12. 0.7 12. 60. 12. 125. 12. SPOT SAMPLE MEAN # OF SAMPLES * * 0. 0. 0.08 1. 0. 1. 0. 1. 87. 1. NORTH MORESBY MEAN # OF SAMPLES (*Ro ) v max' 0.80 4. 81 TABLE1R SKONUN FORMATION SECTION NAME %Rorand ™AK TOC S1 S2 PI QOM HI 01 CAPE BALL WELL MEAN # OF SAMPLES 0.32 403. 22. 16. 41.68 16. 16.3 16. 81.42 16. 0.15 16. 2.2 16. 179. 16. 38. 16. GOLD CREEK WELL MEAN # OF SAMPLES 0.27 418. 7. 4. 24.44 4. 0.97 4. 14.42 4. 0.08 4. 0.70 4. 64. 4. 68. 4. LOG CREEK MEAN # OF SAMPLES 0. 39 420. 2.47 1.32 5.2 0.2 2.64 210. 14. 1. 1. 1. 1. 1. 1. 1. 1. 1. MILLER CREEK MEAN # OF SAMPLES 0.19 1. 0. 0. NADU RIVER WELL MEAN # OF SAMPLES 0.29 400. 10. 4. 6.67 1.36 8. 7.72 0.46 0.9 64. 199 8. PORT LOUIS WELL MEAN # OF SAMPLES 1.05 486. 24. 13. 10.45 14. 0.73 14. 10.3 14. 0.07 14. 0.87 14. 79. 14. 9. 14. TLELL WELL MEAN # OF SAMPLES 0.27 417. 17. 14. 22.i 15. 7.27 15. 39.12 15. 0.15 15. 1.91 15. 161. 15. 74. 15. TOW HILL WELL MEAN # OF SAMPLES 0.48 430. 45. 36. 36.18 40. 7.17 40. 31.76 40. 0.17 40. 1.19 40. 93. 40. 28. 39. 82 Honna Formation The Conacian Honna Formation is exposed locally between central Graham Island and Langara Island. Maturation values obtained from northwest Graham (1.14 %R°ranci) aQd northern Moresby (0.60 %Ro to 1.01 %Ro_.„v) Islands indicate that the strata are generally mature (Fig. 19). On northwest 111 dA IU cUv Graham Island, vitrinite reflectance values were measured on samples taken from in-situ coal stringers wherever possible. If no coal stringers were found, measurements were taken on shale or sandstone samples which included dispersed organic matter. Maturation values from coal particles averaged less than 0.60 %Roran(j whereas maturation values from samples with dispersed organic matter at or near the same locality ranged from 0.56 %Roran(j to 1.43 %R0rana- The n'8n maturation values associated with dispersed organic matter is considered the result of reworking of more mature organic matter in older strata. SKONUN FORMATION The Miocene-Pliocene Skonun Formation is exposed locally on eastern Graham Island and underlies most of Graham Island and Hecate Strait. The DOM for the Skonun Formation is generally immature with the exception of the mature succession in the Port Louis well (west central Graham Island) and the basal strata in the Tow Hill Well (northeast Graham Island). Regional organic maturation values for the basal strata of the Skonun Formation increase from east to west with vitrinite reflectance values ranging from 0.31 %Rorand at Cape Ball to 1.33 %Rorand at Port Louis (Fig. 20). Maturation Gradients Maturation gradients determined from outcrop and well sections are important for calculating the thickness of eroded strata, the thickness of strata within the oil window, and for estimating the paleogeothermal gradient. In this study, the vertical variation in DOM was determined from a total of 12 vitrinite reflectance/depth plots derived from six onshore petroleum exploration wells and six measured CAPE BALL WELL VITRINITE REFLECTANCE (XRorand) 2 X 1000 R—SQUARE = 0.64 MATURATION CRAOItNT = 0.18 XRorand/km B 83 GOLD CREEK WELL VITRINITE REFLECTANCE (XRorand) R-SOUARC = 0.96 MATURATION GRADIENT o 0.21 XRorand/km NADU RIVER WELL VITRINITE REFLECTANCE (XRorand) R—SQUARE = 0.83 MATURATION CRADIENT = 0.19 XRorand/km PORT LOUIS WELL VITRINITE REFLECTANCE (XRorand) R-SQUARE = 0.60 MATURATION GRADIENT = 0.30 XRorand/km Figure 25. Maturation gradients for the Tertiary Skonun Formation. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +, standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Roran<j)/km] is derived from the regression line; a) at the Cape Ball well; b) at the Gold Creek well; c) at the Nadu River well; d) at the Port Louis well 84 TLELL WELL VITRINITE REFLECTANCE (XRorand) R-SOUARE = 0.88 MATURATION GRADIENT = 0.20 XRorand/km TOW HILL WELL VITRINITE REFLECTANCE (XRorand) 900 2 Q ,200 1 -Tat V • 1 \ o z —1 z c m m z TO o A —\ o -n > m O TO z ~C m > A —i o i z • REFLECTANCE VALUES - ANOMALOUS REFLECTANCE VALUE R-SQUARE = 0.90 MATURATION GRADIENT = 0.25 XRorand/km 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) \ o cz m F o m z HAI o o n X > —i > > > I- za O ca J— O m > o X) O z —i r c > T* IA —i o o z O c TJ • C o TRI z ON CP r-> > rn • VITRINITE REFLECTANCE SS > o it: "- UNCONFORMITY o z ^] o m R—SQUARE = 0.86 c ca MATURATION GRADIENT = 0.73 XRorand/km "TJ H CAA-86-01 : ONWARD POINT VITRINITE REFLECTANCE (XRorand) I o L c n T EN HA O n o X > —i > > 1 ACE LBIA RLO FORI sno: z TTE MATI 1 d o la z 1 o c -o • VITRINITE REFLECTANCE M ANOMALOUS REFLECTANCE VALUE . - COVERED INTERVAL •• DIKE/SILL R-SOUARE = 0.93 MATURATION GRADIENT = 0.45 XRorand/km Figure 25. Maturation gradients for the Tertiary Skonun Formation. Points are mean vitrinite reflectance values. Error bars are calculated as mean values _+ standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Ro j)/km] is derived from the regression line; e) at the Tlell well; f) at rand the Tow Hill well. Maturation gradients for the Cretaceous Haida Formation; g) at north Lauder Point; h) at Onward Point BC-SECTION-CAA-02 : NORTH CUMSHEWA INLET VITRINITE REFLECTANCE (ZRorand) 2 100 ,— o > :IAN FAN z z JC 33 Z Z f— r— > cz i— C C RAS PLII rn o NCT SIC ENSBAC ROUP ION FM X > z o X o 00 ~i O 33 m m 7K R-SQUARE = 0.45 -n MATURATION GRADIENT - 0.35 XRorand/km 85 BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (%Rorand) • VITRINITE REFLECTANCE " ANOMALOUS REFLECTANCE VALUE R-SQUARE = 0.53 MATURATION GRADIENT = 0.28 XRorand/krr K 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (%Rorand) • VITRINITE REFLECTANCE • ANOMALOUS REFLECTANCE VALUES R-SQUARE - 0.58 MATURATION GRADIENT - 0.78 XRorand/km 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (%Rorand) CO CZ z > EM CO cz (/) za o > z CO > z o LANDS -KUNG FORM —( TO LATE ;A GROUP ATION ISSVI NOR — o IAN a ~~~ a i— • VITRINITE REFLECTANCE m " ANOMALOUS REFLECTANCE VALUES m - FAULT MB - SANOILANDS-MIDDLE CONTACT m TO R-SQUARE = 0.53 MATURATION GRADIENT = 0.65 XRorand/km Figure 25. Maturation gradients for the Jurassic Maude and Yakoun Groups. Points are mean vitrinite reflectance values. Error bars are calculated as mean values +. standard deviation. Regression lines are calculated with a least square fit algorithm. R-square value represents the goodness of fit. Maturation gradient [log(%Roiand)/km] is derived from the regression line; i) at Cumshewa Inlet; j) at Rennell Junction. Maturation gradients for the Triassic Kunga Group; k) at Fredrick Island; 1) at Kennecott Point 86 outcrop sections (Fig. 25). Numerous other outcrop sections were measured but were not of sufficient length to obtain accurate maturation gradients. The maturation data best fit a log (vitrinite reflectance) linear depth relationship and the maturation gradients were derived with a first order regression algorithm. Maturation gradients for the Skonun Formation range from 0.18 log (%R°rarKi) Am t0 0.25 log (%Roran(j)/km on eastern Graham Island and 0.30 log (%Rorana)/km on western Graham Island (Figs. 25A-F). Haida Formation maturation gradients (Figs. 25G and 25H) range from 0.45 log (%R°rancj)/km at Onward Point (Skidegate Inlet) to 0.73 log (%R0rand)Am at Lauder Point (northwest Graham Island). Maturation gradients for the Maude Group (Figs. 251 and 25J) vary from 0.28 log (%R°rancj) Am at Rennell Junction (central Graham Island) to 0.35 log (%R°rand)Am at Cumshewa Inlet (northern Moresby Island). Two maturation gradients were derived for the Kunga Group on northwest Graham Island; 0.78 log (%Roran(j)/km at Fredrick Island and 0.65 log (%Roran(j) Am at nearby Kennecott Point (Figs. 25K and 25L). Thickness of Eroded Strata The thickness of eroded strata can be calculated by extrapolating the measured maturation gradient to the zero maturation level of 0.15 %Rorand assuming a constant paleogeothermal gradient (Bustin, 1986; England and Bustin, 1986). If the paleogeothermal gradient is not constant, the predicted thickness of eroded strata can be over- or under- estimated. In the study area, high heat flow associated with Mesozoic or Tertiary volcanism (Sutherland Brown, 1966; Cameron and Tipper, 1985) is considered to have increased the paleogeothermal gradients for 5-25 million years in the Middle-Late Jurassic or Tertiary (as discussed later) resulting in elevated maturation gradients. Hence, the erosional thickness values may be 87 underestimated for strata which were affected by high heat flow. The calculated values, therefore, represent a minimum estimate. The calculated thickness of eroded strata for the Skonun Formation ranges from 375 m at the Tlell well to 1685 m at the Port Louis well (Table 2). The amount of eroded strata increases towards the north except at the Nadu River well (1160 m) which lies proximal to a structural high in the underlying Masset Formation (Sutherland Brown, 1968) suggesting the area was differentially uplifted following deposition of the Skonun Formation. Predicted thickness of eroded strata (Table 2) for Cretaceous outcrop sections increases from north Lauder Point (745 m) to Onward Point (1500 m). The predicted thickness of eroded strata increases from Rennell Junction (1725 m) to Cumshewa Inlet (1985 m) for Jurassic outcrop sections. Predicted values for Triassic outcrop sections range from 735 m at Kennecott Point to 1040 m at Fredrick Island. The maturation gradients are too variable in the study area (as a result of local thermal effects associated with volcanism or plutonism) to be confidently extrapolated to adjacent areas in order to calculate thicknesses of eroded strata such as done by Bustin (1986). Depth to the Oil Window The stratigraphic depth to the top of the oil window (Table 2) was calculated by extrapolation of the maturation gradient to 0.50 %R°ran(j which corresponds to the onset of oil generation for Types II and III organic matter (Dow, 1977). Similarly, the stratigraphic depth to the base of the oil window (Table 2) has been established by extrapolation of the maturation gradient to 1.35 %R0rancj which corresponds to the base of the oil window for Types II and III organic matter (Dow, 1977). 88 TABLE 2 WELL NAME (LOCATION) MINIMUM VITRINITE REFLECTANCE (%Rorand> MAXIMUM VrTRINrTE REFLECTANCE <%Rora„d> CALCULATED DEPTH TO THE TOP AND BASE OF THE OIL WINDOW (M) CALCULATED THICKNESS OF ERODED SECTION (M) TERTIARY STRATA SKONUN FORMATION (EXPLORATION WELLS) CAPE BALL 0.18 0.42 GOLD CREEK 0.22 0.36 NADU RIVER 0.24 0.33 PORT LOUIS 0.81 1.38 TLELL 0.18 0.34 TOW HILL 0.28 0.72 2283-4685 2010-4104 1622-3917 0053-1486 2291-4491 1125-2864 615 530 1160 1685 375 985 NORTH LAUDER POINT 0.53 ONWARD POINT 0.7 1.05 1.1 **-563 "-624 745 1500 CUMSHEWA INLET 0.82 RENNELL JUNCTION 0.44 0.91 0.57 "-554 178-1747 1985 1725 FREDRICK ISLAND 0.97 KENNECOTT POINT 0.36 131 0.70 "-183 69-733 1040 735 89 Depth to the oil window values cannot be calculated for areas from which measured maturation gradients were not obtained. The maturation gradients are too variable to extrapolate to adjacent areas as discussed in the previous section. Calculated depths to the top of the oil window for the Skonun Formation strata in the six onshore wells on Graham Island generally increase from north to south and range from a minimum of 53 m on west Graham Island (Port Louis well) to a maximum of 2291 m on east Graham Island (Tletl well). Similarly, the calculated depths to the base of the oil window range increase from west (1486 m at the Port Louis well) to east (4685 m at the Cape Ball well) Graham Island (Table 2). Thicknesses of strata within the oil window range from 1433 m on west Graham Island (Port Louis well) to 2402 m on east Graham Island (Cape Ball well). Exposed Cretaceous strata at north Lauder Point and Onward Point are within the oil window and the calculated stratigraphic depth to the base of the oil window ranges from 563 m at north Lauder Point to 624 m at Onward Point (Table 2). Thicknesses of strata within the oil window range from 563 m at north Lauder Point to 624 m at Onward Point. Exposed Jurassic strata at Cumshewa Inlet are within the oil window and the calculated stratigraphic depth to the base of the oil window is 554 m. The calculated stratigraphic depth to the top and base of the oil window is 178 m and 1747 m respectively at Rennell Junction (Table 2). Thicknesses of strata within the oil window range from 554 m at Cumshewa Inlet to 1569 m at Rennell Junction. The calculated stratigraphic depth to the top and base of the oil window for exposed Triassic strata at Kennecott Point range from 69 m to 733 m. Strata at Fredrick Island are within the oil window and the calculated stratigraphic depth to the base of the oil window is 183 m (Table 2). Thicknesses of strata within the oil window range from 183 m at Fredrick Island to 664 m at Kennecott Point. THERMAL MODELLING 90 Numerous researchers have demonstrated that the DOM depends upon the thermal history of the strata (Karweil, 1955; Lopatin, 1971; Bostick, 1973; Waples, 1980). Numerical models have been developed by petroleum and coal geologists to help predict organic maturation based on knowledge of the thermal history, or conversely, to interpret the thermal history where the levels of organic maturation are known. Most models are based on some form of the Arrhenius equation (including the Arrhenius model used in this study) as described by Karweil (1955) and Tissot and Espitalie (1975): K = Ae(-E/RT> where E = activation energy T = absolute temperature A=frequency factor K=reaction constant R = universal gas constant Lopatin (1971) suggested that the level of organic maturation could be represented as an integration of the time-temperature history of the strata where maturation increases exponentially with temperature and linearly with time (see Waples, 1980). In the Lopatin model, the total level of organic maturation (TTI) is the sum of interval maturations calculated for 10 °C heating increments: nmax TTI= ]j£ ATn(rn> nmin where nmin = lowest temperature interval nmax = highest temperature interval n=number of temperature intervals r = 2 (assuming the DOM doubles for every 10 °C increment of heating) Both the modified Arrhenius and Lopatin models are utilized in this study to predict paleogeothermal gradients, fractional kerogen conversion to liquid hydrocarbons, and timing of hydrocarbon generation for six onshore wells and six measured outcrop sections in the study area. In order to estimate paleogeothermal gradients, the measured maturation gradients were modelled using integral forms of the Arrhenius and Lopatin equations. The models iteratively solve for maturation gradients assuming a constant burial history but varying geothermal gradient. The base of each well or outcrop section was modelled with varying input geothermal gradients until the predicted DOM was similar to the measured level of organic maturation. Attempts to model maturation gradients (rather than single points) were unsuccessful possibly due to poor age constraints on the strata, or nonlinearities in sedimentation rates and non-constant paleogeothermal gradients throughout the depositional histories of the strata. In this study, the Arrhenius model utilizes a constant activation energy (E = 218 kJ/mol) and frequency factor [A = (5.45) ] based on average values for Type II and Type III organic matter within the maturation ranges measured in this study (Wood, 1988). The Lopatin model, on the other hand, assumes that the reaction rate doubles with every 10 °C increase in temperature. Thermal conductivity, and surface temperature (5 °C) are held constant and compacted rock thickness are assumed for both the Arrhenius and Lopatin models. Variations in thermal conductivity with depth, and changes in rock thickness resulting from compaction are not considered here because they are beyond the precision of the geology constraints. Burial Histories The following section outlines the burial histories which form the basis for the maturation models presented later (ages based on Geological Society of America time scale, 1983). Burial histories were reconstructed for the base of the modelled stratigraphic horizon using data acquired from published and unpublished sources. Maximum burial depth is estimated as the sum of the current thickness and the predicted eroded thickness of strata. Due to the paucity of data constraining the ages and thicknesses of strata as well as the timing of tectonic elements, the burial histories presented here are preliminary and, at best, considered a first approximation. Accordingly, conservative estimates based upon the available geologic data have been utilized to quantify parameters used in modelling. Due to the relative insensitivity of both the Arrhenius and Lopatin models to time for all temperature ranges, the timing of uplift has little effect on the DOM. Therefore, the timing of erosional events does not require a great deal of accuracy for the models to yield useful results. TERTIARY BURIAL HISTORIES Burial histories for Skonun Formation strata in the six onshore well sections are described together due to their similarity (Figs. 26A, 27A, 28A, 29A, 30A, 31A). The age of the Tertiary Skonun Formation is poorly known and has been estimated to be Late Miocene to Early Pliocene by Martin and Rouse, 1966; Sutherland Brown, 1968 whereas Cameron and Hamilton (1988) consider the Skonun Formation to be as old as Early Miocene (18 Ma). On Graham Island, deposition of the Skonun Formation followed the culmination of Masset volcanism between 20 Ma and 25 Ma (Hickson, 1988). There are, however, intercalations of sediments similar to Skonun Formation strata within flows of the Masset Formation. For this study, the Skonun Formation is assumed to have been deposited between 18 Ma and 2 Ma followed by uplift in the Quaternary (1.6 Ma to the present). Maximum burial depths are presumed to have been attained at 2 Ma and range from 1625 m at the Tlell well to 3150 m at the Port Louis well. CRETACEOUS BURIAL HISTORIES At north Lauder Point (Fig. 32A) and Onward Point Fig. 33A), Cretaceous strata were deposited beginning with the Albian Haida Formation (113-97.5 Ma). It is presumed that the Cenomanian-Turonian Skidegate Formation (97.5-88.5 Ma) and the Conacian Honna Formation (88.5-87.5 Ma) were deposited following Haida Formation deposition in order to account for the calculated thickness of eroded strata values at north Lauder Point (745 m) and at Onward Point (1500 m). A period of erosion removing the Skidegate and Honna Formations occurred between 87.5 Ma (Conacian) and 45 Ma (estimated initial CAPE BALL WELL SKONUN FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 20 18 16 M 12 10 8 6 4 H—'—I—1—i—'—I—'—I 1 I '—H B CAPE BALL WELL VITRINITE REFLECTANCE (/SRorand) 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 30 °C/KM 93 CAPE BALL WELL VITRINITE REFLECTANCE (/SRorand) 0.1 1 10 2 J 4 6 (/I < £ 8 u. O g _i 5 '2 UJ 14 16 18 20 GRADIENT = 30 °C/KM CAPE BALL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (%Rorond) 0.1 1 10 200 400 600 800 1000 1200 ^ 1400 X UJ 1600 a 1800 2000 2200 2400 2600 2800 20 i 40 30 3000 °C/KM Figure 26. Tertiary Skonun Formation strata at the Cape Ball well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j)t0 facilitate comparison of slopes 94 CAPE BALL WELL VITRINITE REFLECTANCE (XRorand) 0 200 400 eoo 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2S00 3000 GRADIENT = 35 °C/KM CAPE BALL WELL VITRINITE REFLECTANCE (XRorand) i 12 GRADIENT = 35 °C/KM CAPE BALL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 \ 400 1 600 I 800 I 1000 1 1200 \Y — 1400 ; y. X ': \ \ 1— o. 1600 • \ • o ; \\ 1800 • V 2000 ;U 2200 U\ 2400 i U 2600 i\\ 2800 30 • 1; 40 35 3000 °C/KM Figure 26. Tertiary Skonun Formation strata at the Cape Ball well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 35 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 35 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes GOLD CREEK WELL SKONUN FORMATION BURIAL HISTORY . AGE (MILLIONS OF YEARS) 20 18 16 14 12 10 8 6 4 2 I 1 1 1 I 1 I ' I 1 I 1 I 1 I -- 200 400 600 -• BOO 1000 1200 . O m -- 1400 "D —t X 1600 ^ 1B00 -• 2000 2200 2400 2600 -- 2800 3000 B 95 GOLD CREEK WELL VITRINITE REFLECTANCE (%Rorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2B00 3000 GRADIENT = 30 °C/KM GOLD CREEK WELL VITRINITE REFLECTANCE (XRorand) GRADIENT = 30 °C/KM GOLD CREEK WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 800 1000 1200 — 1400 X S; 1600 a 1800 2000 2200 2400 2600 2800 20 : 40 30 3000 °C/KM Figure 27. Tertiary Skonun Formation strata at the Gold Creek well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j) to facilitate comparison of slopes GOLD CREEK WELL VITRINITE REFLECTANCE (%Rorond) 0.1 1 10 o 200 400 .600 BOO 1000 1200 «— 1400 \ X £ 1600 o 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 40 °C/KM 96 GOLD CREEK WELL o (/) z o VITRINITE REFLECTANCE (%Rorand) GRADIENT = 40 °C/KM GOLD CREEK WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (/CRorand) 0.1 1 10 200 l 400 600 1 800 1000 1200 i \ \ 1400 ': 1 X | 1 \ CL 1600 i 1 ; Q ; 1 \ 1800 \ \ \ 2000 \ \\ 2200 \\ \ 2400 \ \ \ 2600 \\\ 2800 30 ' 50 40 3000 ^ °C/KM Figure 27. Tertiary Skonun Formation strata at the Gold Creek well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes NADU RIVER WELL SKONUN FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 20 18 16 14 12 10 8 6 4 2 3 1 1 fe^—1—1 1 1 1—1—1—|—>—|—i—|—>—|—i— H—1— - 0 ; ZOO • 400 - 600 ; 800 • 1000 : 1200 ; 1400 ; 1600 DEPTH (M) : 1800 : 2000 • 2200 ; 2400 - 2600 • 2800 ; 3000 B NADU RIVER WELL VITRINITE REFLECTANCE (XRorand) 0.1 1 10 I 200 400 600 BOO 1000 1200 w 1400 X p- 1600 Q 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 27 °C/KM 97 NADU RIVER WELL VITRINITE REFLECTANCE (XRorand) GRADIENT = 27 °C/KM NADU RIVER WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 800 1000 1200 2~ — 1400 X Eb ,60° Q 1800 2000 2200 2400 2600 2800 20 ; 40 27 3000 °C/KM Figure 28. Tertiary Skonun Formation strata at the Nadu River well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 27 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 27 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^R-0ran(j)to facilitate comparison of slopes NADU RIVER WELL VITRINITE REFLECTANCE (%Rorand) 0 200 400 soo 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 40 "C/KM 98 NADU RIVER WELL VITRINITE REFLECTANCE (%Rorand) GRADIENT = 40 °C/KM NADU RIVER WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (%Rorand) 0.1 1 10 0 I ' ' 200 \ 400 I 600 BOO | 1000 ft 1200 u\ 3 1400 u\ X Q- 1600 n\ o 1800 2000 2200 2400 2600 2800 3000 30 '• 1 '• 50 40 °C/KM Figure 28. Tertiary Skonun Formation strata at the Nadu River well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=40 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes PORT LOUIS WELL SKONUN FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 20 IB 16 14 12 10 8 6 4 2 3 i k 1 I 1 I 1 1 1 H—'— • 0 • 200 ': 400 • 600 J 800 | 1000 - 1200 ; 1400 ; 1600 - 1800 DEPTH - 2000 ; 2200 • 2400 ; 2600 ; 2800 '- 3000 • 3200 \ 3400 : 3600 B PORT LOUIS WELL VITRINITE REFLECTANCE (%Rorand) 0.1 1 10 0 200 400 600 800 1000 1200 1400 5 1600 — X 1800 0_ £ 2000 2200 2400 2600 2800 3000 3200 3400 3600 GRADIENT = 45 °C/KM 99 PORT LOUIS WELL VITRINITE REFLECTANCE (XRorand) 0.1 1 10 0 2 J 4 / 6 / in DC < / > 8 I Li-CS (/I Z 10 g j 1 3 12 / Ul 2 / r— 14 16 18 20 GRADIENT = 45 °C/KM PORT LOUIS WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 o I 1 200 1 400 1 600 I 800 1000 1200 |\ 5" ;l " 1400 .1 '• X •\ '• 1— gj ,60° •1 V o : 1 ': 1800 j \ 2000 n \ 2200 |l \ 2400 2600 n \ 2800 40 ' 50 45 3000 »C/KM Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 (^0^'otan^)to facilitate comparison of slopes PORT LOUIS WELL VITRINITE REFLECTANCE (%Rorand) 0.1 1 10 o 200 400 600 800 1000 1200 1400 \ 2 1600 \ — \ J 1800 \ \ Q 2000 \ 2200 \ 2400 \ 2600 \ 2800 \ 3000 \ 3200 3400 3600 GRADIENT = 55 °C/KM 100 PORT LOUIS WELL VITRINITE REFLECTANCE (%Rorand) GRADIENT = 55 °C/KM PORT LOUIS WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (KRorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 "C/KM Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 55 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=55 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^"^^^ to facilitate comparison of slopes PORT LOUIS WELL FRACTIONAL KEROGEN CONVERSION 0.01 o.l PORT LOUIS WELL FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Q 200 400 600 aoo 1000 1200 1400 , 2 1600 1800 Q 2000 2200 2400 2600 2800 3000 3200 3400 3600 101 Figure 29. Tertiary Skonun Formation strata at the Port Louis well (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 30 °C/km) TLELL WELL SKONUN FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 20 IB 16 14 12 10 B 6 4 2 0 1 h— i i —|——|——j—i—|—i—|—i—|—i— • 0 ; 200 - 400 • 600 ; 800 ; 1000 - 1200 O : 1400 TJ X • 1600 ,—, ; 1800 - 2000 ; 2200 : 2400 ~ 2600 : 2B00 : 3000 B 10 TLELL WELL VITRINITE REFLECTANCE (XRorand) 0 200 400 600 BOO 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 32 °C/KM TLELL WELL VITRINITE REFLECTANCE (XRorand) GRADIENT = 32 log (XRorand/km) TLELL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 800 1000 1200 2~ 1400 X »— & 1600 a 1800 2000 2200 2400 2600 2800 20 ; 40 32 3000 °C/KM Figure 30. Tertiary Skonun Formation strata at the Tlell well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 32 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 32 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran<j)t0 facilitate comparison of slopes TLELL WELL VITRINITE REFLECTANCE (%Rorond) 0 200 400 600 800 1000 1200 1400 1600 1B00 2000 2200 2400 2600 2800 3000 GRADIENT = 42 °C/KM 103 TLELL WELL VITRINITE REFLECTANCE (%Rorand) o £ 'o g _i _J 5. 12 GRADIENT = 42 °C/KM TLELL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (%Rorand) 0.1 1 10 200 \ 400 600 800 it 1000 i| 1200 DEPTH (M) 1400 1600 1800 2000 2200 2400 2600 1 2800 3000 30 i ' '• 50 42 °C/KM Figure 30. Tertiary Skonun Formation strata at the Tlell well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=42 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=42 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes TOW HILL WELL SKONUN FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 20 18 16 14 12 10 8 6 4 2 B TOW HILL WELL VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 800 1000 1200 — 1400 X 2; 1600 o 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 42 °C/KM 104 TOW HILL WELL VITRINITE REFLECTANCE (XRorand) GRADIENT = 42 °C/KM TOW HILL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 : I 50 42 °C/KM Figure 31. Tertiary Skonun Formation strata at the Tow Hill well (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 42 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient=42 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°rand)t0 facilitate comparison of slopes TOW HILL WELL MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0 1 1 10 • 200 \ 400 1 600 | 800 1000 1200 \ \\ 1400 : \ • X \ \\ a. 1600 \ \\ a \\ 1800 \ \\ 2000 \ u 2200 \ \ \ 2400 \ \\ 2600 \ \\ 2800 40 • \ '• 60 51 3000 °C/KM Figure 31. Tertiary Skonun Formation strata at the Tow Hill well (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=51 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=51 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes 87-DV-15 : NORTH LAUDER POINT HAIDA FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 120 100 80 60 40 20 J r \ ^ l l J—l 1 r ° \ / 200 \ / • 400 \ / - 600 \ / '• aoo : 1000 - 1200 o m -1400 "TJ -H X • 1600 »-» : 1800 • 2000 • 2200 • 2400 ; 2600 - 2800 - 3000 B 106 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 — 1400 X Si 1600 o 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 88 °C/KM 87-DV- -15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) 0.1 1 10 20 40 60 LO < 80 >- / O 100 y (MILLIONS O UJ 140 2 f— 160 180 200 220 GRADIENT = 88 °C/KM 87-DV-15 : NORTH LAUDER POINT MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 °C/KM Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 88 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 88 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %R°ran(j) t0 facilitate comparison of slopes 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (%Rorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 98 °C/KM 107 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) GRADIENT = 98 °C/KM 87-DV-15 : NORTH LAUDER POINT MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 1400 1600 2600 2800 3000 110 Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=98 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 98 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Roran(j)t0 facilitate comparison of slopes 87-DV- -15 : NORTH LAUDER POINT FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 o 200 400 600 800 1000 1200 — 1400 X 2; 1600 a 1800 2000 2200 2400 2600 2800 3000 108 87-DV-15 : NORTH LAUDER POINT FRACTIONAL KEROGEN CONVERSION 0.01 o.i i Figure 32. Cretaceous Haida Formation strata at north Lauder Point (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 88 C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 88 C/km) CAA-86-1 : ONWARD POINT HAIDA FORMATION BURIAL HISTORY AGE (MILLIONS OF YEARS) 120 100 80 60 40 20 - ° \ / - 200 \ / ; 400 \ / • 600 : 800 ; 1000 • 1200 o m - 1400 TJ —1 I ; 1600 ; 1800 ; 2000 ;. 2200 • 2400 : 2600 ; 2800 • 3000 B 109 CAA-R6-1 : ONWARD POINT VITRINITE REFLECTANCE (XRorand) 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 70 °C/KM CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (XRorond) Ld 140 2 GRADIENT = 70 °C/KM CAA -86- 1 : ONWARD POINT MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 1 200 400 600 BOO 1000 1200 —' 1400 X Oj 1600 a 1800 2000 2200 2400 2600 2800 60 1 ; 80 . 70 3000 °C/KM Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to rand facilitate comparison of slopes CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (JSRorand) 0 200 400 soo soo 1000 1200 1400 1E00 1800 2000 2200 2400 2E00 2800 3000 GRADIENT = 80 °C/KM 110 CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (%Rorand) 2 Ld 140 GRADIENT = 80 °C/KM CAA-86-1 : ONWARD POINT MODELLED GRADIENTS VITRINITE REFLECTANCE (%Rorand) "C/KM Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 80 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 80 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^Ro^) to facilitate comparison of slopes CAA-86-1 : ONWARD POINT FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 0 200 400 eoo soo 1000 1200 1400 1600 1B00 2000 2200 2400 2600 2800 3000 111 CAA-86-1 : ONWARD POINT FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Figure 33. Cretaceous Haida Formation strata at Onward Point (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 70 °C/km) 112 deposition of the subaerial erupted Masset Formation) (Cameron and Tipper, 1985; Cameron and Hamilton, 1988; Hickson, 1988). There is insufficient data to conclude if the Masset Formation was deposited at north Lauder Point or Onward Point. However, even if the Masset Formation was deposited in these areas, it is unlikely that the burial depth of the Skonun Formation exceeded the maximum depth of burial attained in the Cretaceous and thus the Masset Formation would have little effect on the modelled DOM except near dikes or sills. The Skonun Formation is assumed to have never been deposited in these areas because both north Lauder Point and Onward Point are west of the presumed depositional edge of the Skonun Formation. JURASSIC BURIAL HISTORIES At Cumshewa Inlet (Fig. 34A) and Rennell Junction (Fig. 35A), Lower Jurassic strata of the Maude Group were deposited from the Early Pliensbachian to the Aalenian (198-183 Ma) to a total estimated depth of 300 m (Cameron and Tipper, 1985). Minor erosion or non-deposition within the Maude Group are documented by Cameron and Tipper (1985). Following Maude deposition, sediments of the Lower Bajocian Yakoun Group (Graham Island and Richardson Bay Formations) were deposited at the Rennell Junction section while partially contemporaneous volcanic facies of the Yakoun Group were erupted at Cumshewa Inlet (Cameron and Tipper, 1985). In order to account for the predicted thickness of eroded strata at Rennell Junction (1725 m) and Cumshewa Inlet (1985 m), the Upper Bathonian to Lower Callovian Moresby Group (Robber Point, Newcombe, and Alliford Formations) are assumed to have been deposited following Yakoun deposition and then uplifted and eroded during the Late Jurassic and Early Cretaceous. The Longarm Formation (Upper Valanginian-Lower Barremian) is inferred to have been deposited, and partially or totally eroded before the Albian (113 Ma). The Cretaceous Haida, Skidegate, and Honna Formations appear to have been deposited during Albian to Conacian time (113 Ma to 87.5 Ma) followed by uplift and erosion until the initiation of Masset volcanism (45 Ma). 113 There is no evidence for deposition of the Masset Formation or the Skonun Formation at Rennell Junction or Cumshewa Inlet. Even if Masset Formation or Skonun Formation strata were deposited, the burial depths of Lower Jurassic sediments are assumed to be less than the maximum burial depths previously attained, thereby having little effect on maturation levels. TRIASSIC BURIAL HISTORIES At Fredrick Island (Fig. 36A) and Kennecott Point (Fig. 37A), the Early to Late Norian middle limestone member and the Sinemurian Sandilands Formation of the Kunga Group were buried until the Lower Pliensbachian. There is no evidence for post-Sinemurian Jurassic deposition north of Rennell Sound on western Graham Island (Tipper, pers. comm., 1988); therefore, a period of non-deposition or uplift is assumed during Early Pliensbachian to Early Callovian time (Maude, Yakoun, and Moresby Groups). The Longarm Formation was deposited during the Late Valanginian-Early Barremian followed by uplift and partial erosion as is evident from exposures of the Longarm Formation north of Fredrick Island (Tipper, pers. comm., 1988). Cretaceous Haida, Skidegate, and Honna Formations are exposed north of Fredrick Island and are assumed to have been deposited in the Fredrick Island-Kennecott Point area. Deposition of the Masset Formation is estimated to not have been sufficient to bury the Triassic strata to exceed maximum burial depths attained during the Cretaceous. The Skonun Formation is assumed to never have been deposited in the area; both Fredrick Island and Kennecott Point are west of the inferred depositional edge of the Skonun Formation. Maturation Histories Maturation histories derived from both Arrhenius (Figs. 26B-37B, and 26C-37C) and Lopatin (Figs. 26E-37E, and 26F-37F) numerical methods incorporate the burial histories reviewed above for the modelled sections. Measured maturation gradients are compared with calculated paleogeothermal gradients in CAA-86-2 : CUMSHEWA INLET MAUDE GROUP BURIAL HISTORY AGE (MILLIONS OF YEARS) 220 200 180 180 140 120 100 80 60 40 20 ) | | I I ' ' ' f > • • | • ' 1. |.l • 1 | • • • | • • • 0 \ - 200 1 - 400 • - 600 : 800 • 1000 - 1200 - O m - 1400 TJ -i * X • 1600 " : 1800 • 2000 : 2200 - 2400 : 2600 : 2800 ; 3000 B 114 CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 55 °C/KM o cn z o _i _j 2 UJ 3 CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) GRADIENT = 55 °C/KM CAA-86-2 : CUMSHEWA INLET MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient=55 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 55 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 to facilitate comparison of slopes CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (/SRorand) 0 200 400 SOO 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 1 GRADIENT = 55 °C/KM 115 CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (/SRorand) UJ 140 2 GRADIENT = 55 °C/KM CAA-86-2 : CUMSHEWA INLET MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 — 1400 X I— S; 1600 2200 2400 2600 2800 3000 Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 55 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=55 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes H CAA-86-2 : CUMSHEWA INLET FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 116 o —J _J 2 UJ 2 CAA-86-2 : CUMSHEWA INLET FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Figure 34. Jurassic Maude Formation strata at Cumshewa Inlet (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient=55 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 55 °C/km) BC-SECTION-10 : RENNELL JUNCTION MAUDE AND YAKOUN GROUPS BURIAL HISTORY AGE (MILLIONS OF YEARS) 220 200 180 160 140 120 100 80 60 40 20 0 I " 1 I I " 1 I " I I 1 -- 200 -'- 400 • '. 600 -'• 800 -- 1000 -- 1200 o -- 1400 Hid: -: 1600 -: 1800 2000 -: 2200 -; 2400 -- 2600 -- 2800 -'- 3000 B BC-SECTION- 10 : RENNELL JUNCTION VITRINITE REFLECTANCE (%Rorand) 0.1 1 10 200 400 600 BOO 1000 f 1200 I — 1400 X £ 1600 l o 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 45 °C/KM 117 BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (SCRorand) GRADIENT = 45 °C/KM BC-SECTION-10 : RENNELL JUNCTION MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 o 200 \ 400 1 600 I BOO 1 1000 % 1200 \V\ ~- 1400 \\\ X \ \ '•• 2j 1600 '• \ '•• \ \ \ 1800 \\'\ 2000 \\\ 2200 \\ \ 2400 \\ \ 2600 \ \ \ ZBOO 40 • ' 50 45 3000 ^ °C/KM Figure 35. Jurassic Maude Formation strata at Rennell Junction (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient=45 C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient=45 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to ranc facilitate comparison of slopes BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (%Rorand) 0 200 400 600 BOO 1000 1200 1400 1600 1B00 2000 2200 2400 2600 2800 3000 GRADIENT = 49 °C/KM 118 BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (XRorand) GRADIENT = 49 °C/KM BC-SECTION-10 : RENNELL JUNCTION MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) 1400 1600 1B00 2000 2200 2400 2600 2B00 3000 °C/KM Figure 35. Jurassic Maude Formation strata at Rennell Junction (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=49 °C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient=49 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to facilitate comparison of slopes 87-DV-19 : FREDRICK ISLAND KUNGA GROUP BURIAL HISTORY AGE (MILLIONS OF YEARS) 220 200 180 160 140 120 100 80 60 40 20 0 I I 1 " I 0 200 400 -• 600 BOO -- 1000 1200 a n -•1400 TJ —I X 1600 ^ 1800 -- 2000 2200 2400 -- 2600 2800 3000 B 119 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (%Rorand) 0 200 400 600 BOO 1000 1200 " 1400 X t— £; 1600 a 1B00 2000 2200 2400 2600 2800 3000 V GRADIENT = 90 °C/KM 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) o i/j z o 2 UJ 2 GRADIENT = 90 °C/KM 87-DV-MODELLED 19 : FREDRICK GRADIENTS ISLAND VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 800 1000 1200 DEPTH (M) o a a o 1B00 2000 \ 100 2200 2400 90 2600 2S00 °C/KM 80 3000 Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 %Ro .) to rand facilitate comparison of slopes 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 100 °C/KM 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) GRADIENT = 100 °C/KM 120 87-DV-19 : FREDRICK ISLAND MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorand) Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 100 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 100 C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^"^^^ to facilitate comparison of slopes 87-DV-19 : FREDRICK ISLAND o 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 FRACTIONAL KEROGEN CONVERSION 0.1 121 87-DV-19 : FREDRICK ISLAND FRACTIONAL KEROGEN CONVERSION o.oi o.i i Figure 36. Triassic Sandilands Formation strata at Fredrick Island (see text): h) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km); i) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (constant geothermal gradient = 90 °C/km) 87-DV-12 : KENNECOTT POINT KUNGA GROUP BURIAL HISTORY AGE (MILLIONS OF YEARS) 220 200 180 160 140 120 100 80 60 40 20 ( » 1 \ 1 1 1 | ' f '•*(*•'• | f | I | .1. I .•.( ° ; 200 : 400 v\ / - 600 \ / : 800 \ / • 1000 V ; - 1200 - O m r 1400 TJ -i I - 1600 ~ ; 1800 : 2000 : 2200 ; 2400 : 2600 - 2800 - 3000 B 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (%Rorond) 122 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 65 °C/KM 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) GRADIENT = 65 °C/KM 87-DV-MODELLED 12 : KENNECOTT POINT GRADIENTS VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 \ 400 1 600 1 800 1 1000 1200 5. 1400 X 2; 1600 o 1800 I 2000 \V\ 2200 \\\ 2400 \\ \ 2600 \\ \ 2600 60 65 70 3000 °C/KM Figure 37. Triassic Sandilands Formation strata at Kennecott Point (see text): a) interpreted burial history for the base of the Skonun Formation assuming uniform subsidence and uplift rates derived from published and unpublished data; b) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 65 °C/km); c) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (constant geothermal gradient = 65 °C/km); d) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 ^ROJ^JJ) TO facilitate comparison of slopes 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorond) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 GRADIENT = 70 °C/KM 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) 160 180 GRADIENT = 70 °C/KM 123 87-DV-12 : KENNECOTT POINT MODELLED GRADIENTS VITRINITE REFLECTANCE (XRorond) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 °C/KM Figure 37. Triassic Sandilands Formation strata at Kennecott Point (see text): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 70 C/km); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (constant geothermal gradient = 70 °C/km); g) calculated geothermal gradients and measured maturation gradients are plotted through the origin (0.15 t^°^lj3xan(j) t0 facilitate comparison of slopes 124 Figures 26D-37D for the Arrhenius model and Figures 26G-37G for the Lopatin model. The base of the oldest modelled stratigraphic horizon is shown for each section. The fractional kerogen conversion to petroleum relative to depth and time (based on the Arrhenius model) is illustrated for some well or outcrop sections in Figures 29H, 32H, 33H, 34H, 36H, and 291, 321, 331, 341, 361) Wood (1988) has shown that at high heating rates, the Lopatin model underestimates the DOM (relative to the Arrhenius model) and overestimates the DOM at low heating rates (relative to the Arrhenius model). A comparison of the paleogeothermal gradients derived from both the Arrhenius and Lopatin type models (Table 3) illustrates that in all cases but one, the Lopatin model required a higher paleogeothermal gradient than the Arrhenius model suggesting that these strata have undergone high heating rates sometime during their history (Wood, 1988). Alternatively, the assumption in the Lopatin model that the reaction rate (and hence DOM) doubles every 10 °C (for temperatures between 50 °C and 150 °C and activation energies between 42 kJ/mol and 105 kJ/mol; Tissot and Welte, 1984) may not apply for Mesozoic and Tertiary strata in the Queen Charlotte Islands due to high temperatures (> 150 °C) attained during Yakoun and Masset volcanism. The Lopatin model, therefore, underestimates the DOM for strata which have been heated beyond 150 °C. Results and Interpretations The Queen Charlotte Islands are in an island arc tectonic setting; therefore, it is likely that heat flow (and thus paleogeothermal gradients) were influenced by volcanism and subduction and varied laterally between adjacent areas and with time (Watanabe et al., 1977; Cameron and Tipper, 1985). The following section discusses two possible thermal regimes for Mesozoic and Tertiary strata; constant, and variable paleogeothermal gradients. In order to account for the measured level of organic maturation (Figs. 26-37), the models predict paleogeothermal gradients in excess of 40 °C/km. Geologic evidence, however, suggests that heat flow (and paleogeothermal gradients) increased during volcanic/plutonic episodes in the Middle-Late Jurassic (Yakoun volcanism) and Eocene-Miocene (Masset volcanism). In this study, models which 125 TABLE 3 CONSTANT GEOTHERMAL GRADIENT MODEL PREDICTED PALEOGEOTHERMAL PREDICTED PALEOGEOTHERMAL WELL (SECTION) NAME GRADIENT (°C/KM) GRADIENT (°C/KM) (LOCALITIES) (ARRHENIUS MODEL) (LOPATIN MODEL) TERTIARY STRATA SKONUN FORMATION (EXPLORATION WELLS) CAPE BALL GOLD CREEK NADU RIVER PORT LOUIS TLELL TOW HILL CRETACEOUS STRATA HAIDA FORMATION (OUTCROP) NORTH LAUDER POINT ONWARD POINT JURASSIC STRATA MAUDE AND YAKOUN GROUPS (OUTCROP) CUMSHEWA INLET RENNELL JUNCTION TRIASSIC STRATA KUNGA GROUP (OUTCROP) FREDRICK ISLAND 90 100 KENNECOTT POINT 65 730 30 27 45 32 42 35 40 40 55 42 51 70 98 80 55 45 55 49 VARIABLE GEOTHERMAL GRADIENT MODEL (30 °C/KM BACKGROUND PALEOGEOTHERMAL GRADIENT) WELL (SECTION) NAME PREDICTED PEAK PREDICTED PEAK PALEOGEOTHERMAL GRADIENT PALEOGEOTHERMAL GRADIENT (°C/KM) (ARRHENIUS MODEL) (°C/KM) (LOPATIN MODEL) CRETACEOUS STRATA HAIDA FORMATION (OUTCROP) NORTH LAUDER POINT ONWARD POINT JURASSIC STRATA MAUDE AND YAKOUN GROUPS (OUTCROP) CUMSHEWA INLET RENNELL JUNCTION TRIASSIC STRATA KUNGA GROUP (OUTCROP) FREDRICK ISLAND KENNECOTT POINT 130 130 97 83 150 100 145 145 118 105 160 115 126 allow for variable geothermal gradients are utilized to incorporate the assumed high heat flow during volcanic episodes. The modelled geothermal gradients were increased (up to 150 °C/km) above the ambient background geothermal gradient (assumed to be 30 °C/km) for short intervals of time consistent with geological evidence (assumed to be between 183-178 Ma for Yakoun volcanism, and between 35-10 Ma for Masset volcanism). The background geothermal gradient was chosen to be similar to average paleogeothermal gradients (30 °C/km) modelled for the Skonun Formation. Paleogeothermal gradients for Tertiary strata are considered to be the least effected by high heat flow associated with volcanism because the Skonun Formation was deposited after the cessation of Yakoun and Masset volcanism. However, if Mesozoic background paleogeothermal gradients were higher than the modelled 30 °C/km geothermal gradients, little effect in the levels of organic maturation are predicted in that the maximum temperatures (which were attained during volcanic episodes when heat flow was substantially elevated above the background levels) have the most pronounced effect on maturation (Figs. 38-43). The paleogeothermal gradients predicted for each section are documented in the following section. The predicted paleogeothermal gradients were derived from geothermal gradients which were modelled to attain the measured DOM. Both the Arrhenius and Lopatin models generally yielded similar results, therefore only the Arrhenius model is described in the following discussion. Results from the Lopatin model are presented for comparative purposes in Table 3. TERTIARY PALEOGEOTHERMAL GRADIENTS Paleogeothermal gradients predicted by the Arrhenius model (assuming a constant thermal regime) range from 27 °C/km to 45 °C/km (Nadu River and Port Louis wells respectively) and average 30 °C/km. CRETACEOUS PALEOGEOTHERMAL GRADIENTS Predicted paleogeothermal gradients for Cretaceous strata (assuming a constant thermal regime) range from 70 °C/km at Onward Point to 88 °C/km to north Lauder Point. Variable thermal regime modelling with 30 C/km background paleogeothermal gradients predicts peak paleogeothermal gradients up to 130 °C/km during the culmination of Masset Formation volcanism (between 35 Ma and 10 Ma) for Cretaceous strata at both Onward and north Lauder Points (see burial histories). Significant lateral variation in heat flow during Masset time between northwest and southeast Graham Island is not predicted by the Arrhenius model. JURASSIC PALEOGEOTHERMAL GRADIENTS Predicted paleogeothermal gradients for a constant thermal regime for Jurassic strata range from 45 °C/km at Rennell Junction to 55 °C/km at Cumshewa Inlet. Predicted peak paleogeothermal gradients (assuming a variable thermal regime with 30 °C/km background paleogeothermal gradients) range up to 83 °C/km at Rennell Junction and 97 °C/km at Cumshewa Inlet during the culmination of Yakoun volcanism between 183 Ma and 178 Ma. The increased paleogeothermal gradients in Cumshewa Inlet suggest that the Jurassic strata at that locality were more proximal to a source of high heat flow than at Rennell Junction. TRIASSIC PALEOGEOTHERMAL GRADIENTS Although Fredrick Island and Kennecott Point are proximally located, higher paleogeothermal gradients are predicted at Fredrick Island (90 °C/km) than at Kennecott Point (65 °C/km) assuming a constant thermal regime. Peak paleogeothermal gradients (assuming a variable thermal regime with 30 °C/km background paleogeothermal gradients) range up to 100 °C/km at Kennecott Point and 150 °C/km at Fredrick Island during the culmination of Masset volcanism between 35 Ma and 10 Ma. A higher geothermal gradient predicted for Fredrick Island (relative to Kennecott Point) is probably due to increased heat flow from Masset feeder dikes/sills located closer to Fredrick Island than to Kennecott Point. 87-DV- -15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 \ 800 \ 1000 \ 1200 2* •~- 1400 I £j ,60° a 1800 2000 2200 2400 2600 2800 30 °C/KM AVERAGE GRADIENT 3000 130°C/KM PEAK GRADIENT B 87-DV- -15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) 0.1 1 10 I 20 40 60 (MILLIONS OF YEARS) M O 00 j Ul 140 2 h-160 180 200 220 30 °C/KM AVERAGE GRADIENT 130°C/KM PEAK GRADIENT 128 87-DV-15 : NORTH LAUDER POINT FRACTIONAL KEROGEN CONVERSION 0.01 o.i i o 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 87-DV-15 : NORTH LAUDER POINT FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Figure 38. Cretaceous Haida Formation strata at north Lauder Point (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient) 129 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 MOO 1600 1B00 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 140°C/KM PEAK GRADIENT 87-DV-15 : NORTH LAUDER POINT VITRINITE REFLECTANCE (XRorand) o i/i z g 2 30 °C/KM AVERAGE GRADIENT 140°C/KM PEAK GRADIENT Figure 38. Cretaceous Haida Formation strata at north Lauder Point (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (140 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (140 °C/km peak geothermal gradient) CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 130°C/KM PEAK GRADIENT B 130 CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (XRorand) 30 °C/KM AVERAGE GRADIENT 130°C/KM PEAK GRADIENT CAA-86-1 : ONWARD POINT FRACTIONAL KEROGEN CONVERSION o.oi o.i 1 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 CAA-86-1 : ONWARD POINT FRACTIONAL KEROGEN CONVERSION o.oi o.i i Figure 39. Cretaceous Haida Formation strata at Onward Point (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (130 °C/km peak geothermal gradient) CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (%Rorand) 0 200 400 600 600 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 145°C/KM PEAK GRADIENT CAA-86-1 : ONWARD POINT VITRINITE REFLECTANCE (%Rorand) 2 id 140 30 °C/KM AVERAGE GRADIENT 145°C/KM PEAK GRADIENT Figure 39. Cretaceous Haida Formation strata at Onward Point (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (145 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (145 °C/km peak geothermal gradient) CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) 0 200 400 600 BOO 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 97 °C/KM PEAK GRADIENT B CAA- 86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) 0.1 1 10 20 40 60 TIME (MILLIONS OF YEARS) Ol >• to O CD o o o o o 180 200 220 30 °C/KM AVERAGE GRADIENT 97 °C/KM PEAK GRADIENT CAA-86-2 : CUMSHEWA INLET FRACTIONAL KEROGEN CONVERSION o.oi o.i i 200 400 600 BOO 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 CAA-86-2 : CUMSHEWA INLET FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Figure 40. Jurassic Maude Group strata at Cumshewa Inlet (variable geothermal gradient model with 30 °C/km average gradient a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (97 °C/km peak geothermal gradient) CAA-86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 118°C/KM PEAK GRADIENT CAA- -86-2 : CUMSHEWA INLET VITRINITE REFLECTANCE (XRorand) 0.1 10 0 20 40 60 .AKJ ) 80 >-u. O 100 t/> ILLIOh 120 3^ LU 2 140 I— 160 180 200 30 °C/KM AVERAGE GRADIENT 220 118°C/KM PEAK GRADIENT Figure 40. Jurassic Maude Group strata at Cumshewa Inlet (variable geothermal gradient model with 30 °C/km average gradient) e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (118 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (118 °C/km peak geothermal gradient) BC-SECTION- 10 : RENNELL JUNCTION VITRINITE REFLECTANCE (XRorand) 0.1 1 10 200 400 600 BOO 1000 1200 2* ~- 1400 X £ 1600 a IBOO 2000 2200 2400 2600 2800 30 °C/KM AVERAGE GRADIENT 3000 83 0 C/KM PEAK GRADIENT B BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (XRorand) 0.1 1 10 20 40 60 (/I % 80 >^ 0 100 (/I z 0 Zi 120 _j 2 UJ 140 2 t— 160 180 • c 200 1 30 °C/KM AVERAGE GRADIENT 220 83 °C/KM PEAK GRADIENT 13 BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (XRorand) 0.1 1 10 . 200 400 600 800 1000 1200 2~ " 1400 X UJ 1600 0 1800 2000 2200 2400 2600 2800 30 °C/KM AVERAGE GRADIENT 3000 105°C/KM PEAK GRADIENT BC-SECTION-10 : RENNELL JUNCTION VITRINITE REFLECTANCE (XRorand) 2 uj 2 30 °C/KM AVERAGE GRADIENT 105°C/KM PEAK GRADIENT Figure 41. Jurassic Maude Group strata at Rennell Junction (variable geothermal gradient model with 30 °C/km average gradient): a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (83 C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (83 °C/km peak geothermal gradient); c) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (105 °C/km peak geothermal gradient); d) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (105 °C/km peak geothermal gradient) 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) 0 200 400 600 BOO 1000 1200 2~ — 1400 SJ 1600 O 1B0O 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 150°C/KM PEAK GRADIENT B 13 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) 30 °C/KM AVERAGE GRADIENT 150° C/KM PEAK GRADIENT 87-DV-19 : FREDRICK ISLAND FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2B00 3000 O to z o _J 2 LJ 2 87-DV-19 : FREDRICK ISLAND FRACTIONAL KEROGEN CONVERSION 0.01 0.1 1 Figure 42. Triassic Kunga Group strata at Fredrick Island (variable geothermal gradient model with 30 °C/km average gradient) a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient); c) fractional kerogen conversion (relative to depth) utilizing a modified Arrhenius model (150 C/km peak geothermal gradient); d) fractional kerogen conversion (relative to time) utilizing a modified Arrhenius model (150 °C/km peak geothermal gradient) 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1800 1800 2000 2200 2400 2 EOO 2800 3000 30 °C/KM AVERAGE GRADIENT 160°C/KM PEAK GRADIENT 136 2 LJ 2 87-DV-19 : FREDRICK ISLAND VITRINITE REFLECTANCE (XRorand) 30 °C/KM AVERAGE GRADIENT 160°C/KM PEAK GRADIENT Figure 42. Triassic Kunga Group strata at Fredrick Island (variable geothermal gradient model with 30 °C/km average gradient): e) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (160 °C/km peak geothermal gradient); f) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (160 °C/km peak geothermal gradient) 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) 0 200 400 600 800 1000 1200 1400 1600 1B00 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 100°C/KM PEAK GRADIENT B 2^ UJ 2 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) 30 °C/KM AVERAGE GRADIENT 100°C/KM PEAK GRADIENT 13 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 30 °C/KM AVERAGE GRADIENT 115°C/KM PEAK GRADIENT o oo z g —i -j 2 UJ 2 87-DV-12 : KENNECOTT POINT VITRINITE REFLECTANCE (XRorand) 30 °C/KM AVERAGE GRADIENT 115°C/KM PEAK GRADIENT Figure 43. Triassic Kunga Group strata at Kennecott Point (variable geothermal gradient model with 30 °C/km average gradient a) maturation history (relative to depth) for the basal strata utilizing a modified Arrhenius model (100 °C/km peak geothermal gradient); b) maturation history (relative to time) for the basal strata utilizing a modified Arrhenius model (100 °C/km peak geothermal gradient); c) maturation history (relative to depth) for the basal strata utilizing a modified Lopatin model (115 °C/km peak geothermal gradient); d) maturation history (relative to time) for the basal strata utilizing a modified Lopatin model (115 °C/km peak geothermal gradient) 138 INTERPRETATION OF AREAL MATURATION TRENDS The paleogeothermal gradients predicted for the Tertiary Skonun Formation are within the average ranges for geothermal gradients (15 °C/km to 64 °C/km) reported from back arc basins found in other parts of the world (Watanabe et al., 1977; and Blackwell et al., 1982). Present day heat flow values for the west coast of North America average 60-80 mW/m (Chapman and Rybach, 1985) and recent heat flow 9 measurements from Moresby Island average 50-60 mW/m (geothermal gradients of approximately 18-20 °C/km; Lewis, pers. comm., 1988) suggesting that onshore heat flow has decreased since Skonun Formation deposition. If constant paleogeothermal gradients are assumed for Mesozoic strata in the Queen Charlotte Islands, geothermal gradients ranging from 45 °C/km to 90 °C/km are required for up to 180 Ma from the Upper Triassic to Middle Eocene (which was predominantly volcanically quiescent). In particular, the Arrhenius model predicts paleogeothermal gradients of 90 °C/km for Triassic strata at Fredrick Island for 180 Ma between the Norian and the Middle Eocene. However, there is no evidence of igneous activity to generate the predicted high heat flow near Fredrick Island until the Tertiary. Similarly, unusually high paleogeothermal gradients are required during periods of volcanic quiescence to produce the maturation levels measured from Jurassic and Cretaceous strata. Similar results are achieved with constant paleogeothermal gradients for other Triassic strata. Thus, a variable thermal regime with a moderate background geothermal gradients and high peak geothermal gradients more reasonably describes Mesozoic maturation than does a constant thermal regime. If the heat flow was higher during volcanic episodes than assumed in the models used here, less time would be required to achieve the same measured DOM. The DOM of Lower Jurassic Maude and Yakoun Group strata increases from Rennell Junction to Cumshewa Inlet. Although burial depths are similar at both localities, variable thermal regime modelling predicts higher peak heat flow during the Lower Bajocian at Cumshewa Inlet (97 oC/km) than at Rennell Junction (83 oC/km). The higher paleogeothermal gradient at Cumshewa Inlet is most likely the result of 139 elevated heat flow from Yakoun Group volcanism or from coeval plutonism on Moresby Island. Furthermore, at Rennell Junction, Yakoun Group sediments (Graham Island and Richardson Bay Formations) were deposited rather than Yakoun andesites (Cameron and Tipper, 1985) suggesting that diminished volcanic activity near Rennell Junction may account for the lower heat flow predicted in central Graham Island. Jurassic strata younger than the Sinemurian Sandilands Formation were probably not deposited in the Fredrick Island-Kennecott Point area, therefore, Yakoun volcanism was most likely not significant to the thermal maturation of Kunga strata. Heat flow associated with Masset feeder dikes and sills near Fredrick Island and Kennecott Point were the most likely cause of the elevated paleogeothermal gradients predicted by maturation modelling. A higher geothermal gradient predicted for Fredrick Island (relative to Kennecott Point) is probably due to increased heat flow from Masset feeder dikes/sills more proximally located to Fredrick Island. Timing of Hydrocarbon Generation The timing of hydrocarbon generation was estimated from numerical modelling (Table 4) using the vitrinite reflectance/time diagrams assuming the oil window is between 0.50 %R°rancj and 1-35 %R°ranci (see Part II). Figures 38C, 39C, 40C, 42C, and 38D, 39D, 40D, 42D illustrate the degree of converted kerogen to petroleum with respect to depth and time for each section (Espitalie et al., 1975) plotted with respect to time and depth. Diagrams for immature strata which have not generated significant amounts of hydrocarbons are not presented. The Tertiary Skonun Formation is everywhere immature with respect to oil generation except at west (Port Louis well) and northeast Graham Island (basal strata of the Tow Hill well). Strata from west Graham Island (Port Louis well) are predicted to have entered the oil window in the Late Miocene (7.6 Ma) and are currently in the oil window (Table 4). The models predicts that strata from northeast Graham Island (basal strata of the Tow Hill well) entered the oil window in the Late Miocene (5.1 140 TABLE 4 CONSTANT GEOTHERMAL GRADIENT MODEL WELL (SECTION) NAME (LOCALITIES) TIMING OF ENTERING AND EXITING OIL WINDOW (MA) (ARRHENIUS MODEL) TIMING OF ENTERING AND EXITING OIL WINDOW (MA) (LOPATIN MODEL) TERTIARY STRATA SKONUN FORMATION (EXPLORATION WELLS) CAPE BALL GOLD CREEK NADU RIVER PORT LOUIS 7.6 Ma, TLELL TOW HILL 5.1 Ma 6.8 Ma, 1.7 Ma * * 4.3 Ma,* CRETACEOUS STRATA HAIDA FORMATION (OUTCROP) NORTH LAUDER POINT ONWARD POINT 88 Ma,* 87 Ma,* 88 Ma,* 87 Ma * JURASSIC STRATA MAUDE AND YAKOUN GROUPS (OUTCROP) CUMSHEWA INLET 169 Ma,* RENNELL JUNCTION 88 Ma, * 159 Ma,* 92 Ma,* TRIASSIC STRATA KUNGA GROUP (OUTCROP) FREDRICK ISLAND KENNECOTT POINT 102 Ma, 83 Ma 90 Ma,* 102 Ma, 85 Ma 87 Ma,* VARIABLE GEOTHERMAL GRADIENT MODEL (30 °C/KM BACKGROUND PALEOGEOTHERMAL GRADIENT) WELL (SECTION) NAME TIMING OF ENTERING AND EXITING OIL WINDOW (MA) (ARRHENIUS MODEL) TIMING OF ENTERING AND EXITING OIL WINDOW (MA) (LOPATIN MODEL) CRETACEOUS STRATA HAIDA FORMATION (OUTCROP) NORTH LAUDER POINT ONWARD POINT 18 Ma,* 18 Ma,* 15 Ma,* 16 Ma * JURASSIC STRATA MAUDE AND YAKOUN GROUPS (OUTCROP) CUMSHEWA INLET 178 Ma,* RENNELL JUNCTION 178 Ma,* 178 Ma,* 178 Ma,* TRIASSIC STRATA KUNGA GROUP (OUTCROP) FREDRICK ISLAND KENNECOTT POINT 20 Ma, 10 Ma 13 Ma,* 17 Ma, 7 Ma 12 Ma* 141 Ma) and never exited the oil window. The generation of hydrocarbons at west and northeast Graham Island (Port Louis and Tow Hill wells) is probably the result of higher paleogeothermal gradients and deeper burial than adjacent strata. Strata from west Graham Island (Port Louis well) are intercalated with Masset volcanics and may be of limited lateral extent suggesting that the area has questionable potential to generate exploitable amounts of liquid hydrocarbons. Oil staining occurs in a thin interval of strata at northeast Graham Island in the Tow Hill well suggesting hydrocarbons may have been generated from Tertiary Skonun Formation. Cretaceous strata at north Lauder Point and Onward Point are presently within the oil window. The Arrhenius model predicts that strata at north Lauder Point and Onward Point entered the oil window during the Early Miocene (18 Ma). Lower Jurassic strata at Cumshewa Inlet and Rennell Junction are mature with respect to hydrocarbon generation and are presently within the oil window. The strata entered the oil window during the Lower Bajocian (178 Ma). Triassic strata from Fredrick Island entered and exited the oil window during the Early and Late Miocene (20 Ma and 10 Ma respectively). The strata at Kennecott Point are mature and are presently within the oil window. Lower predicted paleogeothermal gradients suggest that the strata entered the oil window during the Middle Miocene (13 Ma). Hydrocarbon Generation Relative to Tectonic Elements Major structural deformation in the Queen Charlotte Islands occurred primarily in two episodes: syn- and post- Yakoun volcanism in the Middle and Late Jurassic; and between deposition of the Honna and the Masset Formations in the Late Cretaceous and Early Tertiary. Any hydrocarbons generated from the Skonun Formation postdates the formation of Mesozoic reservoir structures. Given the correct basin 142 geometry and migration paths, Tertiary oil may be trapped in Mesozoic structures. Skonun sourced hydrocarbons may also be pooled in stratigraphic or growth fault traps onshore or in Hecate Strait. Variable paleogeothermal gradient modelling suggests that Cretaceous strata from Graham Island and Triassic strata from northwest Graham Island generated hydrocarbons from the Early Miocene to the present and were available for migration to potential Jurassic and Cretaceous-Tertiary aged structural traps. Jurassic sourced hydrocarbons from central Graham Island and northern Moresby Island were generated from the Bajocian to the present and were available for migration to potential Jurassic and Cretaceous-Tertiary aged structural traps. DISCUSSION Organic maturation of strata on the Queen Charlotte Islands is primarily controlled by high heat flow adjacent plutons and dike/sill swarms on Moresby Island and by 'normal' subsidence on Graham Island. In particular, Mesozoic strata on Moresby Island are overmature as a result of pluton emplacement during the Middle-Late Jurassic and possibly the Oligocene whereas strata on Graham Island which have not been effected by plutonism are immature to mature (Fig. 44). Large scale plutonic activity in Hecate Strait and Dixon Entrance, however, is not apparent suggesting that Mesozoic and Tertiary aged potential source strata in the offshore are possibly mature and may have sourced and pooled or reservoired hydrocarbons. Commercial hydrocarbon accumulations, therefore, more likely occur offshore in Hecate Strait and Dixon Entrance. The Queen Charlotte Islands have been part of an island arc system since the Sinemurian (Sutherland Brown, 1968; Cameron and Tipper, 1985). During the geologic history of volcanic arcs, average heat flow (and geothermal gradient) can vary significantly from below average up to four times average heat flow depending upon the proximity to the subduction zone (Hasabe et al., 1970; Watanabe et al., 1977; Blackwell et al., 1982). It is therefore likely that the Queen Charlotte Islands have experienced substantial fluctuations in heat flow and thus geothermal gradient in the Mesozoic and Tertiary. Lateral variations in 143 SURFACE MATURATION MAP FOR MESOZOIC AND TERTIARY STRATA Figure 44. Surface maturation trends for Mesozoic and Tertiary strata derived from vitrinite reflectance data (%Rorand). Oil window is between 0.50 %Ro . and 1.35 %Ro rand rand 144 the DOM of various strata on the Queen Charlotte Islands attest to the variable heat flow associated with arc volcanism and plutonism. The Triassic Kunga Group strata on Moresby Island have been subjected to high heat flow are evident from DOM values up to 5.80 %^-°iana- The Sinemurian Sandilands Formation and the Albian Haida Formation best illustrate the north/south regional variations in organic maturity where the DOM increases substantially from north (0.45 %R°ran(j) to south (4.73 %Roran(j). All strata south of Cumshewa Inlet are overmature as a result of high heat flow associated with pluton emplacement on Moresby Island during the Jurassic and Tertiary. The heat flow was not uniform across Moresby Island. In particular, The DOM for the grey limestone and black limestone members of the Kunga Group increases from west to east with decreasing distance from the Late Jurassic Burnaby Island Plutonic Suite (BIPS; ages range from 156 +. 5 Ma to 142 +. 19 Ma) suggesting that the emplacement of the BIPS was the dominant thermal event on Moresby Island. Hydrothermal activity associated with the BIPS has resulted in sericite and endoskarn alteration (with associated mineralization) and higher levels of organic maturation occur proximal to the Burnaby Island Plutonic Suite than to the adjacent San Christoval Plutonic Suite (SCPS). The highest levels of organic maturation, however, are observed in Carpenter Bay near dike/sill swarms associated with the Carpenter Bay Plutonic Suite (CBPS). Anderson (pers. comm., 1988) suggests that the CBPS is Oligocene in age and possibly related to Masset volcanism. Although the lateral extent of the CBPS is limited, organic maturation resulting from Tertiary plutonism and related igneous intrusives appears to overprint earlier maturation events associated with Middle-Late Jurassic plutonism. More detailed sample collection and analysis is required to determine if high heat flow coeval with Masset volcanism is a contributing factor to the regional organic maturation of Moresby Island and Hecate Strait. Mesozoic strata in the Cumshewa Inlet and Skidegate Inlet areas are mature to overmature with Jurassic and Cretaceous strata generally having similar DOM values. The high DOM values may have resulted from hydrothermal activity related to heat flow from distant Jurassic-Tertiary plutonism on Moresby Island or Rennell Sound-Shields Bay. 145 Most of the measured strata (Jurassic Maude, Yakoun, and Moresby Groups) from central Graham Island are mature with some local marginally immature strata. Included in this area are the potential source rocks of the Sandilands and Ghost Creek Formations (see Part II). The lowest measured maturation gradients and modelled paleogeothermal gradients from the Queen Charlotte Islands occur in central Graham Island where maturation tends to increase from east to west (opposite that of Moresby Island) suggesting that thermal effects from Jurassic and Tertiary volcanism on Moresby Island were not pronounced in central Graham Island. Instead, heat flow associated with plutonism near Rennell Sound-Shields Bay may have been the dominant thermal event effected organic maturation in central Graham Island. Deposition of Yakoun and Moresby Group sediments and the lack of equivalent volcanic strata in central Graham Island suggests that Jurassic volcanism may never have been extensive in the area (Cameron and Tipper, 1985). The source potential for central Graham Island is uncertain in that the thermal regime in this area and the lateral extent of the source rocks are poorly known due to the limited outcrop distribution. Organic maturation in northwest Graham Island ranges from immature to overmature with most of the strata ranging from marginally mature to mature. Overmature strata are most likely the result of high heat flow from plutonic activity on Langara Island. High heat flow from Masset igneous intrusives near Fredrick Island has resulted in the local overmaturation of potential Triassic source strata of the Kunga Group. SUMMARY AND CONCLUSIONS 1. Upper Triassic to Sinemurian Kunga Group strata on northwest Graham Island are generally marginally mature (0.45 %R°ran(i) and the major component of the maturation is predicted to have occurred during the Tertiary whereas the major component of the maturation of the Sandilands Formation on central Graham Island and Moresby Island is considered to be generally syn- or post- tectonic (Late Jurassic-Cretaceous). Sandilands Formation strata are marginally mature (0.48 %R°ran(j) on central Graham Island and overmature in Skidegate Inlet (1.35 to 1.75 %R°ranfj)- Au Kunga Group strata on 146 Moresby Island are overmature (2.40 to 5.80 %R°ranci) as a result of high heat flow associated with Middle-Late Jurassic plutonism and the DOM increases from west to east with increasing proximity to the Burnaby Island Plutonic Suite. The DOM near Carpenter Bay increases to 8.31 %R°rand as a result of Oligocene plutonism which has overprinted maturation events associated with Middle-Late Jurassic plutonism (San Christoval and Burnaby Island Plutonic Suites). 2. Jurassic strata (Maude, Yakoun, and Moresby Groups) from central Graham Island are marginally mature to mature and the DOM increase from east to west with decreasing distance from plutonic complexes near Rennell Sound-Shields Bay. The level of organic maturation increase from central Graham Island (0.43 %Roran(j) to northern Moresby Island (1.58 %Roran(j). The major component of the maturation is considered to be generally syn- or post- tectonic (Late Jurassic-Cretaceous). 3. The DOM of Cretaceous strata on Moresby Island increases from north (1.53-2.43 %R°max) to central (2.31-4.78 %R°ran<j) Moresby Island. Maturation values for Cretaceous strata on Graham Island increase from 0.33 %R°ran(im tne northwest to 2.21 %Roran£j in Skidegate Inlet. The major component of the maturation is generally considered to be Cretaceous and Tertiary. 4. Tertiary strata are generally immature with the exception of the mature succession on west Graham Island (Port Louis well) and northeast Graham Island (basal strata of the Tow Hill well). Regional organic maturation values for the basal strata of the Skonun Formation increase from east (0.31 %R°rana at Cape Ball) to west (1.33 %R°ran(j a* P°rt Louis). The major component of the maturation is considered to have occurred during the Late Tertiary. 5. Time-temperature modelling suggests that the measured maturation gradients would require constant paleogeothermal gradients ranging from 45 to 90 °C/km (Arrhenius model) for up to 180 million years. Variable geothermal gradient modelling (assuming a background paleogeothermal gradient of 30 °C/km), on the other hand, predicts high heat flow with peak geothermal gradients ranging from 83 °C/km on central Graham Island to 150 °C/km on Fredrick Island during Yakoun (183-178 Ma) and Masset 147 volcanism (35-10 Ma). Higher peak temperatures than those predicted in modelling require shorter heating times to attain the measured level of organic maturation. 6. The thickness of eroded strata has been calculated from maturation gradients (assuming 0.15 %Roran(j as zero maturation level and constant maturation gradients). The calculated thickness of eroded strata for the Tertiary Skonun Formation ranges from 375 m at east Graham Island (Tlell well) to 1685 m at west Graham Island (Port Louis well). Twice as much strata has been eroded from Onward Point (1500 m) than north Lauder Point (745 m). Similar amounts of strata have been removed from Jurassic sections at Cumshewa Inlet (1985 m) and Rennell Junction (1725 m). 1040 m of strata have been eroded from Fredrick Island and 735 m of strata have been eroded from Kennecott Point. 7. Similar results are predicted for modified Arrhenius and Lopatin time-temperature modelling. Generally, the Arrhenius model predicts lower paleogeothermal gradients than the Lopatin model as a result of rapid heating of the strata or too high an activation energy (E = 218 kJ/mol) utilized here by the Arrhenius model (relative to the Lopatin model). Variable geothermal time-temperature modelling suggests that Tertiary strata at west Graham Island (Port Louis) and northeast Graham Island (Tow Hill well) entered the oil window during the Late Miocene and are still within the oil window. Tertiary strata on east Graham Island are immature and never entered the oil window as a result of shallow burial depths and low paleogeothermal gradients (<32 °C/km) than west Graham Island. Cretaceous strata on northwest Graham Island and Skidegate Inlet entered the oil window during the Early Miocene and are still within the oil window. Jurassic strata on central Graham Island and north Moresby Island entered the oil window during the Bajocian and are still within the oil window as a result of shallow burial depths. Triassic strata at Fredrick Island entered the oil window during the Early Miocene and exited during the Late Miocene whereas strata at Kennecott Point entered the oil window later during the Middle Miocene and are still within the oil window as a result of lower paleogeothermal gradients. 148 REFERENCES Anderson, R.G. 1988 Jurassic and Cretaceous-Tertiary plutonic rocks on the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 213-216. Armstrong, R.L. 1988 Mesozoic and Early Cenozoic magmatic evolution of the Canadian Cordillera: Special Paper 218, Geological Society of America, p. 55-91 Blackwell, D.D., Bowen, R.G., Hull, DA., Riccio, J., and Steele, J.L. 1982 Heat flow, arc volcanism, and subduction in northern Oregon; Journal of Geophysical Research, v. 87, no. BIO, p. 8735-8754 Bustin, R.M. 1986 Organic maturity of Late Cretaceous and Tertiary coal measures, Canadian Arctic Archipelago; International Journal of Coal Geology, v. 6, p. 71-106. Bustin, R.M., Cameron, A.R., Grieve, DA., and Kalkreuth, W.D. 1983 Coal Petrology, its principle, methods, and applications; Geological Association of Canada, Short Course Notes, v. 3., pp. 273 Bostick, N.H. 1973 Time as a factor in thermal metamorphism of phytoclasts; Congres International de Stratigraphie et de Geologie du Carboniferie Septieme, Krefeld. August 23-28,1971. Compte Readu, 2, Illinois State Geologic Survey reprint series 1974-H, p. 183-193. Cameron, B.E.B. 1987 Significance of Lower Jurassic hydrocarbon source rocks in the Cumshewa Inlet area, Queen Charlotte Islands, British Columbia; in Current Research, Part A, Geological Survey of Canada, Paper 87-1A, p. 925-928. Cameron, B.E.B. and Tipper, H.W. 1985 Jurassic stratigraphy of the Queen Charlotte Islands, British Columbia; Geological Survey of Canada, Bulletin, v. 365, 49 p. Cameron, B.E.B. and Hamilton, T.S. 1988 Contributions to the stratigraphy and tectonics of the Queen Charlotte Basin, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-IE, p. 221-227. Chapman, D.S., and Rybach, L. 1985 Heat flow anomalies and their interpretation; Journal of Geodynamics, v. 4, p. 3-37. Coney, PJ., Jones, D.L., and Monger, J.W.H. 1980 Cordilleran suspect terranes; Nature, v. 288, p. 329-333. Davis, A. 1978 The reflectance of coal; in Analytical Methods for Coal and Coal Particles, C. Karr, ed., London, Academic Press, 1, p. 27-28. Dow, W.G. 1977 Kerogen studies and geologic interpretations; Journal of Geochemical Exploration, 7, p. 79-99. 149 England, T.D J. and Bustin, R.M. 1986 Thermal maturation of the western Canadian sedimentary basin south of the Red Deer River: 1) Alberta Plains; Bulletin of Canadian Petroleum Geology, v. 34, p. 71-90. Espitalie, J., Deroo, G., Marquis, F. 1985 Rock-Eval pyrolysis and its applications; Institut Francais du Petrole, reprint 27299, 132 pp. Fogarassy, JA.S. and Barnes, W.C. 1988 Stratigraphy, diagenesis and petroleum reservoir potential of the mid- to Upper Cretaceous Haida and Honna formations of the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-IE, p. 265-268. Galloway, W.E. 1974 Deposition and diagenetic alteration of sandstone in northeast Pacific arc-related basins: implications for greywacke genesis; Geological Society of America Bulletin, v. 85, p. 379-390. Hasabe, K., Fujii, N., and Uyeda, S. 1970 Thermal processes under island arcs; Tectonophysics, 10, p. 335-355. Haggart, J.W. 1987 On the age of the Queen Charlotte Group of British Columbia; Canadian Journal of Earth Sciences, v. 24, p. 2470-2476. Hamilton, T. 1985 Volcanics of the Cenozoic Masset Formation: implications for geological and tectonic evolution of the Queen Charlotte Islands, British Columbia, Canada; Geological Society of America, Cordilleran Section Annual Meeting, Program with Abstracts, Vancouver, British Columbia, May 8-10, p. 359 Hickson, C J. 1988 Structure and stratigraphy of the Masset Formation, Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-IE, p. 269-274. Hillhouse, J.W. 1977 Paleomagnetism of the Triassic Nicolai Greenstone, McCarthy Quadrangle, Alaska; Canadian Journal of Earth Sciences, 14, p. 2578-2592. Irving, E., Woodsworth,G J., Wynne, P J., and Morrison, A. 1985 Paleomagnetic evidence for displacement from the south of the Coast Plutonic Complex, British Columbia; Canadian Journal of Earth Sciences, 22, p. 584-598. Jones, D.L., Silberling, N J., and Hillhouse, J. 1977 Wrangellia-A displaced terrane in northwestern North America; Canadian Journal of Earth Sciences, 14, p. 2565-2577. Karweil, J. 1955 The metamorphism of coals from the standpoint of physical chemistry; Zeitschrift der Geologischen gesellschaft, 107, p. 132-139. Lopatin, N.V. 1971 Temperature and geologic time as factors in coalification; Izvestiya Akademii Nauk USSR, Seriya Geologicheskaya, 3, p. 95-106. Martin, HA. and Rouse, G.E. 1966 palynology of Late Tertiary sediments from the Queen Charlotte Islands, British Columbia; Canadian Journal of Botony, 44, p. 171-208. 150 Monger, J.W.H., Souther, J.G., and Gabrielse, H. 1972 Evolution of the Canadian Cordillera: a plate tectonic model; American Journal of Sciences, 272, p. 577-602. Muller, J.E., Northcote, K.E., and Carlisle, D. 1974 Geology and mineral deposits of Alert Bay-Cape Scott map-area, Vancouver Island, British Columbia. Geological Survey of Canada, Paper 74-8. 77 pp. Muller, J.E. 1977 Evolution of the Pacific Margin, Vancouver Island and adjacent areas; Canadian Journal of Earth Sciences, 14, p. 2062-2085. Souther, J.G. 1977 Volcanism and tectonic environments in the Canadian Cordillera-a second look, in Volcanic regimes in Canada, ed. W.R A. Baragar, L.C. Coleman, and M.Hall. Geological Association of Canada, Special Paper 16, p. 3-24. Souther, J.G. 1988 Implications for hydrocarbon exploration of dyke emplacement in the Queen Charlotte Islands, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-IE, p. 241-245. Sutherland Brown, A. 1968 Geology of the Queen Charlotte Islands; British Columbia Department of Mines and Petroleum Resources Bulletin 54, 226 pp. Tissot, B.P. and Espitalie. J. 1975 L'evolution thermique de la matiere organique des sediments: Applications d'une simulation mathematique. Rev. Inst. Fr. Pet. 30, p. 743-777. Tissot, B.P. and Welte, D.H. 1984 Petroleum Formation and Occurrence. Springer-Verlag, Berlin, 699 pp. Watanabe, T., Langseth, M.G., and Anderson, R.N. 1977 Heat flow in back-arc basins of the western Pacific; in Island Arcs, Deep Sea Trenches, and Back-Arc Basins, Maurice Ewing Ser., vol. 1, ed. M. Talwani and W.C. Pitman III, p. 137-161, AGU, Washington, D.C, 1977. Waples, D.W. 1980 Time and temperature in petroleum formation with application of Lopatin's method to petroleum exploration; American Association of Petroleum Geologists, Bulletin 64, p. 916-926. Wood, DA. 1988 Relationships between thermal maturity indices calculated using Arrhenius equation and Lopatin method: implications for petroleum exploration; American Association of Petroleum Geologists, vol. 72, #2, p. 115-134. Woodsworth, G J. 1988 Karmutsen Formation and the east boundary of Wrangellia, Queen Charlotte Basin, British Columbia; in Current Research, Part E, Geological Survey of Canada, Paper 88-1E, p. 209-212. Yole and Irving, 1980 Displacement of Vancouver Island: paleomagnetic evidence from the Karmutsen Formation; Canadian Journal of Earth Sciences, 17 p. 1210-1228. PART II SOURCE ROCK POTENTIAL OF MESOZOIC AND TERTIARY STRATA OF THE QUEEN CHARLOTTE ISLANDS 152 ABSTRACT The hydrocarbon source potential for Mesozoic and Tertiary strata in the Queen Charlotte Islands has been determined by Rock-Eval pyrolysis. Mean total organic carbon (TOC) contents are generally low to moderate (0.1 to 3.6 %) and some organic-rich intervals occur throughout the succession. Horizons with high TOC values up to 10.3 % occur in the Upper Triassic black limestone member of the Kunga Group and 11.2 % in the Lower Jurassic Whiteaves Formation. Generally, Mesozoic and Tertiary strata contain Type III organic matter except for the Upper Triassic-Lower Jurassic Kunga Group and the Lower Jurassic Ghost Creek Formation which contain oil and gas prone Type II and significant amounts of oil prone Type I organic matter. Lateral variations in TOC and the quality of organic matter (QOM) for Mesozoic strata on Moresby Island are primarily related to the level of organic maturation. High heat flow associated with plutonism on Moresby Island has resulted in generally poor hydrocarbon source potential due to high levels of maturation of the strata. Equivalent Triassic and Jurassic strata on Graham Island are generally immature to mature and have fair to good hydrocarbon source potential. Hydrocarbon source potential of Cretaceous and Tertiary strata on Graham Island is controlled primarily by the level of organic maturation and to a lesser extent depositional patterns. Cretaceous strata from Moresby Island are generally overmature and have poor source potential whereas equivalent strata from Graham Island are immature to overmature and have fair to moderate gas source potential. The Cretaceous Haida and Honna Formations generally contain terrestrially derived Type III organic matter with poor to fair gas source potential. The Skidegate Formation contains a mixture of Types II and III organic matter and has fair gas generative potential. The Haida Formation contains only terrestrially derived Type III organic matter whereas the Skidegate contains less Type III organic matter and more Type II organic matter. The Tertiary Skonun Formation contains abundant, generally immature coal and lignite with some gas source potential. Mature resinite horizons containing hydrogen-rich organic matter have fair 153 to good oil and gas source potential. Siltstone and shale facies of the Skonun Formation contain moderate amounts of Type II organic matter and have good hydrocarbon source potential. 154 INTRODUCTION The Queen Charlotte Islands contain a thick sedimentary sequence which includes potential source and reservoir strata. The documented occurrence of numerous oil seeps, oil shales, and carbonaceous black shales suggest that hydrocarbons have been generated in the past and may have accumulated in commercial quantities (Cameron and Tipper, 1985; Cameron, 1987; Bustin and Macauley, 1988; Snowdon et al., 1988). To date, the lateral and vertical variations in source rock quality for Mesozoic and Tertiary strata in the Queen Charlotte Islands have not been documented. The purpose of this study is to establish the source rock potential of sedimentary strata on the Queen Charlotte Islands. Bustin and Macauley (1988) have previously documented the DOM and source rock quality for Lower Jurassic oil shales found in central Graham Island and Skidegate Inlet and Snowdon et al. (1988) have performed preliminary organic geochemical analysis on oil seeps from Tertiary strata. The present study has been expanded from the initial work of Bustin and Macauley (1988) to include the entire stratigraphic sequence (Mesozoic to Tertiary) for all of the Queen Charlotte Islands region. Rock-Eval pyrolysis in conjunction with petrologic and organic maturation data are used here to identify and asses potential source strata and delineate their stratigraphic and areal extent. Microscopic and geochemical analysis of organic matter are an important part of petroleum exploration in assessing the hydrocarbon source potential of sedimentary strata. Geochemical data from Rock-Eval pyrolysis (Espitalie et al., 1977) can be used to establish the quantity, type, and thermal maturity of organic matter in sedimentary rocks (Tissot and Welte, 1984). Combined with organic facies and thermal maturity data, Rock-Eval analysis can be used to identify the lateral and vertical extent of potential source strata. 155 METHODS Sample Preparation One thousand four hundred and sixty outcrop and well samples were analyzed by Rock-Eval pyrolysis (Espitalie et al., 1977; Peters, 1986) and organic petrographic techniques (Bustin et al., 1985). Whole rock samples were crushed with ring and centrifugal grinders to approximately -60 mesh particle size. Coal and lignite samples were crushed and sieved to between -50 and -200 mesh particle size to eliminate ultra-fme particles which adversely effect pyrolysis results. The crushed whole rock samples were split for both Rock-Eval pyrolysis (80 to 100 mg) and vitrinite reflectance analyses. Coal and lignite samples weighing between 5 and 30 mg were layered in crushed, pure quartz prior to Rock-Eval pyrolysis to prevent carbon caking of the Rock-Eval pyrolysis instrument. Measured Parameters Rock-Eval pyrolysis provides several measurements to characterize potential source rocks. The SI peak (mg HC/g rock) represents hydrocarbons distilled from the whole rock (2 minutes at 300 °C). The S2 peak (mg HC/g rock) represents hydrocarbons pyrolyzed from kerogen at temperatures between 300 °C and 600 °C (Espitalie et al., 1977). The S3 peak is a measure of the volatilized carbon dioxide between temperatures of 300 °C and 390 °C (mg HC/g rock). The total organic carbon content (TOC) is determined by oxidizing the residual organic matter in air at 600 °C and summed with SI, S2, and S3 peaks (Espitalie et al., 1977). Outcrop samples are commonly depleted in SI and S2 values as a result of oxidation of the organic matter. Similarly, oxidation from erosional events near unconformities can result in SI and S2 depletion. The temperature of maximum S2 hydrocarbon generation (Tmax) reflects the degree of organic maturation (Espitalie et al., 1977). The oil birth line occurs at a TmaK value between 430-435 °C for Types II and III organic matter. The oil death line occurs at a T value of 450 °C for Type II organic matter 156 and at 465 °C for Type III organic matter (Espitalie et al., 1977). Type I organic matter has Tmax values ranging from 460 °C to 470 °C and generally displays a poor correlation between organic maturity and Tmax(Link>1988)-Calculated Parameters In addition to the aforementioned measured Rock-Eval parameters, additional parameters calculated from the SI, S2, S3, and TOC values can be used to determine the nature and quality of potential source rocks. The production index (PI) is calculated as the ratio S1/(S1 + S2) which is a measure of thermal maturity. PI values between 0.1 and 0.4 define the oil window (Peters, 1986). With increasing hydrocarbon generation, PI values increase to 1.0 marking the exhaustion of the hydrocarbon generative potential of the source kerogen. Anomalously high PI values indicate hydrocarbon accumulation and anomalously low PI values indicate hydrocarbon depletion (Espitalie et al., 1985; Peters, 1986). The hydrogen index (HI), defined as S2/TOC, and the oxygen index (OI), defined as S3/TOC, are used to classify organic matter with a hydrogen index/oxygen index (HI/OI) diagram as described by Espitalie et al. (1977). HI values > 600 mg HC/g CQrg suggests oil prone Type I organic matter, HI values between 300 and 600 mg HC/g CQrg suggests oil and gas prone Type II organic matter, and HI values < 300 mg HC/g CQrg suggests gas prone Type III organic matter, assuming a DOM equivalent to 0.6 %Ro (Espitalie et al., 1977); The quality of organic matter (QOM), defined as the ratio (Sl + S2)/TOC, is used to determine the type of organic matter and to measure thermal maturity. QOM values vary with the degree of thermal maturation, the type of organic matter, and migration effects of hydrocarbons (Espitalie et al., 1985). High QOM ratios suggest immature to mature hydrogen-rich organic matter. Variations in QOM values which cannot be attributed to differences in the level of thermal maturity are considered to be the result of hydrocarbon migration. 157 RESULTS In this study, lateral and vertical trends in the degree of organic maturation (DOM) and organic matter richness and type were examined to assess the regional hydrocarbon source potential for individual units. Here, average values are reported for interval horizons (group, formation, or informal member) rather than for discreet samples. Source rock data from Rock-Eval pyrolysis is summarized in Table 1 (see Part I). Rock-Eval data are also presented for some formations as TOC histograms (Figure 45), hydrogen index versus Tmax diagrams (Figure 46), hydrogen index versus oxygen index diagrams (Figure 47), and Rock-Eval logs for the onshore Tertiary wells (Figures 48-53). Lateral variations in TOC (Figures 54-69) and QOM (Figures 70-85) are plotted by group, formation, or member. Tmax versus vitrinite reflectance diagrams are in Appendix B. Source rocks are strata which are capable of generating migratable hydrocarbons (Conford, 1984). The hydrocarbon generative potential is primarily controlled by the volume, richness, and thermal maturity of the organic matter within the strata (Dow, 1977; Espitalie et al., 1977; Durand, 1980; Conford, 1984; Tissot and Welte, 1984; Espitalie et al., 1985). The level of organic maturity was determined in this study from vitrinite reflectance (see part I) and Rock-Eval pyrolysis (Tmax and PI). Interpretation of lateral trends in organic maturation and source rock potential of Mesozoic and Tertiary strata on the Queen Charlotte Islands is difficult due to limited lateral continuity of stratigraphic units and limited outcrop distribution. Hence, the interpretations presented in the following sections are based on limited data and are preliminary. Organic Maturation High heat flow associated with volcanism and plutonism is an important control on source rock quality in the Queen Charlotte Islands. Figure 86 illustrates surface maturation trends with respect to TOTAL ORGANIC CARBON HISTOGRAM SKONUN FORMATION (OUTCROP SAMPLE) 2 3 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) " ' r [I 9.70 B 158 TOTAL ORGANIC CARBON HISTOGRAM HONNA FORMATION 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM HAIDA FORMATION 0.10 1.30 2.50 3.70 5.10 6.50 7.70 8.90 TOTAL ORGANIC CARBON (TOC) 10.00 TOTAL ORGANIC CARBON HISTOGRAM SKIDEGATE FORMATION 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, a) Skonun Formation; b) Honna Formation; c) Haida Formation; d) Skidegate Formation 159 TOTAL ORGANIC CARBON HISTOGRAM LONGARM FORMATION 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM ALLIFORD FORMATION 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM NEWCOMBE FORMATION i 11111111111111 11111111111111111 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) H TOTAL ORGANIC CARBON HISTOGRAM ROBBER POINT FORMATION 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, e) Longarm Formation; f) Alliford Formation; g) Newcombe Formation; h) Robber Point Formation TOTAL ORGANIC CARBON HISTOGRAM GRAHAM ISLAND FORMATION 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) 160 TOTAL ORGANIC CARBON HISTOGRAM PHANTOM CREEK FORMATION 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM WHITEAVES FORMATION JUL 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM FANNIN FORMATION 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, i) Graham Island Formation; j) Phantom Creek Formation; k) Whiteaves Formation; 1) Fannin Formation M TOTAL ORGANIC CARBON HISTOGRAM RENNELL JUNCTION FORMATION O.tO 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) N 16 TOTAL ORGANIC CARBON HISTOGRAM GHOST CREEK FORMATION 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) TOTAL ORGANIC CARBON HISTOGRAM SANDILANDS FORMATION 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, m) Rennell Junction Formation; n) Ghost Creek Formation; o) Sandilands Formation TOTAL ORGANIC CARBON HISTOGRAM BLACK LIMESTONE MEMBER (KUNGA GROUP) JUUl 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 TOTAL ORGANIC CARBON (TOC) 162 TOTAL ORGANIC CARBON HISTOGRAM GREY LIMESTONE MEMBER (KUNGA GROUP) Li 0.10 1.30 2.50 3.70 4.90 6.10 7.30 8.50 9.70 TOTAL ORGANIC CARBON (TOC) Figure 45. Histograms of total organic carbon (TOC) content. Class interval is 0.2 % TOC. Data includes outcrop and well cuttings samples. TOC is expressed as a weight percent, p) black limestone member (Kunga Group); q) grey limestone member (Kunga Group) HYDROGEN INDEX vs TMAX SKONUN FORMATION X 300 -Type I 0.5 XRorand Type II 300 350 400 450 500 550 600 TMAX (DEGREES C) B HYDROGEN INDEX vs TMAX HONNA FORMATION Typo I Type 0.5 XRorand 1.35 XRorand 163 300 350 400 450 500 550 600 TMAX (DEGREES C) HYDROGEN INDEX vs TMAX SKIDEGATE FORMATION 2 500 Type I Type 200 -• Type III DISPERSED -S 0.5 XRorand 1.35 XRorand 300 350 400 450 500 550 600 TMAX (DEGREES C) HYDROGEN INDEX vs TMAX HAIDA FORMATION Type Type 0.5 XRorand 1.35 XRorand 350 400 450 500 550 TMAX (DEGREES C) Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC(mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %Rorand (430-435 °C Tmax) to 1.35 <^0^alan^ (465 °C Tmax) define the oil window for Types II and III organic matter, a) Skonun Formation; b) Honna Formation; c) Skidegate Formation; d) Haida Formation HYDROGEN INDEX vs TMAX ALLIFORD FORMATION Type I Type 0.5 %Rorand orand 300 350 400 450 500 550 600 TMAX (DEGREES C) .,164 HYDROGEN INDEX vs TMAX ROBBER POINT FORMATION —. 700 O O I 300 •• \ 0.5 XRorand Type 1 ; \ Type II \ COAL y^ \ .'. Type III \ 1.35 XRorand DISPERSED "\ - 1 1 1 1 1 1 1 1 1 1 1 1 ' i ^li i 7-|-> 1 1 1 1 1 1 1 1 1 300 350 400 450 500 550 600 TMAX (DEGREES C) HYDROGEN INDEX vs TMAX RICHARDSON BAY FORMATION I 300 --.Type I Type II 0.5 XRorand 1.35 XRorand 300 350 400 450 500 550 600 TMAX (DEGREES C) H HYDROGEN INDEX vs TMAX GRAHAM ISLAND FORMATION Type I Type II 0.5 XRorand 350 400 450 SOO 550 TMAX (DEGREES C) Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC(mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430-435 °C Tmax) to 1.35 %Rorand (465 °c Tmax) define the oil window for Types II and III organic matter, e) Alliford Formation; f) Robber Point Formation; g) Richardson Bay Formation; h) Graham Island Formation HYDROGEN INDEX vs TMAX PHANTOM CREEK FORMATION a soo ": \ \ 0.5 JSRorand Type 1 i \ f / Type II \ -• • • • COAL ' \ Type III • \ 1.35 %Rorand DISPERSED - 1 1 ' 1 1 1 1 ' ' 1 1 1 • vl^o^,. .. . . 300 350 400 450 500 550 600 TMAX (DEGREES C) ,165 HYDROGEN INDEX vs TMAX WHITEAVES FORMATION Typo I Type II 0.5 XRorand orand 300 350 400 450 500 550 600 TMAX (DEGREES C) K HYDROGEN INDEX vs TMAX RENNELL JUNCTION FORMATION o t-f-j 600 -• Type I Type 200 f Type III 0ISPERSE0 0.5 XRorand 1.35 XRorand 350 400 450 500 550 TMAX (DEGREES C) HYDROGEN INDEX vs TMAX GHOST CREEK FORMATION Type I Type 0.5 XRorand 300 350 400 450 500 550 600 TMAX (DEGREES C) Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC(mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %Rorand (430-435 °C Tmax) to 1.35 %Rorand C Tmax) define the oil window for Types II and III organic matter, i) Phantom Creek Formation; j) Whiteaves Formation; k) Rennell Junction Formation; 1) Ghost Creek formation M HYDROGEN INDEX vs TMAX SANDILANDS FORMATION I 300 --Type I Type 0.5 XRorand orand 400 450 500 TMAX (DEGREES C) N HYDROGEN INDEX vs TMAX BLACK LIMESTONE MEMBER (KUNGA GROUP) 1 300 Type I 0.5 XRorand Type 166 400 450 500 TMAX (DEGREES C) Figure 46. Hydrogen index/Tmax (HI/Tmax) diagrams. Organic matter types and oil window limits based on Espitalie et al. (1985). [HI = S2/TOC(mg HC/gm CQrg); Tmax °C]. Data includes outcrop and well cuttings samples. 0.50 %R°rand (430-435 °C Tmax) to 1.35 %R°rand (465 C Tmax) define the oil window for Types II and III organic matter, m) Sandilands Formation; n) black limestone member (Kunga Group) HYDROGEN INDEX vs OXYGEN INDEX SKONUN FORMATION Typo I a 600 Typo Type 50 100 150 200 OXYGEN INDEX (S3/TOC) B 167 HYDROGEN INDEX vs OXYGEN INDEX HONNA FORMATION Type I Type Type III 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX SKIDEGATE FORMATION Type I Type ft* • • • I I I I I I* I I I I I 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX HAIDA FORMATION Type I — 700 o o Type II I. Type III 50 100 150 200 OXYGEN INDEX (S3/TOC) Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); Ol = S3/TOC (mg HC/gm Cq )]. Data includes outcrop and well cuttings samples, a) Skonun Formation; b) Honna Formation; c) Skidegate Formation; d) Haida Formation HYDROGEN INDEX vs OXYGEN INDEX LONGARM FORMATION Type n 600 -0 ** Type Type III Ii...! 50 100 150 200 OXYGEN INDEX (S3/T0C) 168 HYDROGEN INDEX vs OXYGEN ALLIFORD FORMATION INDEX Type I Type II Type III 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX NEWCOM8E FORMATION Type Type II Type III 50 100 150 200 OXYGEN INDEX (S3/TOC) H HYDROGEN INDEX vs OXYGEN INDEX ROBBER POINT FORMATION Type I 700 o o Type II Type III 50 100 150 200 OXYGEN INDEX (S3/TOC) Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); OI = S3/TOC (mg HC/gm CQrg)]. Data includes outcrop and well cuttings samples, e) Longarm Formation; f) Alliford Formation; g) Newcombe Formation; h) Robber Point Formation 169 HYDROGEN INDEX vs OXYGEN INDEX RICHARDSON BAY FORMATION Type I Type 30 100 150 200 OXYGEN INDEX (S3/TOC) HYDROGEN INDEX vs OXYGEN INDEX GRAHAM ISLAND FORMATION Type I Type II 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX PHANTOM CREEK FORMATION Type I 700 U o Type 50 100 150 200 OXYGEN INDEX (S3/TOC) HYDROGEN INDEX vs OXYGEN INDEX WHITEAVES FORMATION Type I Type II Type i , * 50 100 150 200 OXYGEN INDEX (S3/T0C) Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); OI = S3/TOC (mg HC/gm Cq )]. Data includes outcrop and well cuttings samples, i) Richardson Bay Formation; j) Graham Island Formation; k) Phantom Creek Formation; 1) Whiteaves Formation 170 M HYDROGEN INDEX vs OXYGEN INDEX FANNIN FORMATION Type I 2 600 --Typo Type 50 100 150 200 OXYGEN INDEX (S3/T0C) N HYDROGEN INDEX vs OXYGEN INDEX RENNELL JUNCTION FORMATION Type 700 o U 400 o Type Type III 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX GHOST CREEK FORMATION Type I x 300 --Type Type 50 100 150 200 OXYGEN INDEX (S3/TOC) HYDROGEN INDEX vs OXYGEN INDEX SANDILANDS FORMATION Type I Type Type 50 100 150 200 OXYGEN INDEX (S3/TOC) Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQ); OI = S3/TOC (mg HC/gm Corg)]- Data includes outcrop and well cuttings samples, m) Fannin Formation; n) Rennell Junction Formation; o) Ghost Creek Formation; p) Sandilands Formation Qf HYDROGEN INDEX vs OXYGEN INDEX BLACK LIMESTONE MEMBER (KUNGA GROUP) Type I Type 50 100 150 200 OXYGEN INDEX (S3/T0C) HYDROGEN INDEX vs OXYGEN INDEX GREY LIMESTONE MEMBER (KUNGA GROUP) Type I ci 600 + Type 50 100 150 200 OXYGEN INDEX (S3/T0C) Figure 47. Hydrogen index/Oxygen index (HI/OI) diagrams. Maturation pathways modified from Espitalie et al. (1985). [HI = S2/TOC (mg HC/gm CQrg); OI = S3/TOC (mg HC/gm C)]. Data includes outcrop and well cuttings samples, q) black limestone member (Kunga Group); r) grey limestone member (Kunga Group) 172 CAPE BALL WELL TMAX ORGANIC MATURATION C°C) 300 400 500 —i i i i • • • • i o o CM-CD O O O o ^ o 2 « Q O O o o CN O o: O o: IO. o-o; CO QOM QUALITY OF ORGANIC MATTER (mg HC/g ROCK) 0 2 4 6 8 10 -i—i i_j i • • • i i HI HYDROGEN INDEX (mg HC/g ROCK) 0 150 300 450 600 • • PI PRODUCTION INDEX (S1/S1+S2) 0 0.5 1 Figure 48. Rock-Eval logs for the Cape Ball well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm C defines a oil and gas source, HI from 300+ defines an oil source. PI values Between 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 173 GOLD CREEK WELL TMAX ORGANIC MATURATION (°C) 300 400 500 o o O O O O o 2 » 0_ UJ o a o o o o CS o o CD o; CD o-o CO QOM QUALITY OF ORGANIC MATTER (mg HC/g ROCK) 0 2 4 6 8 10 HI HYDROGEN INDEX (mg HC/g ROCK) 0 150 300 450 600 • ' PI PRODUCTION INDEX (S1/S1+S2) 0.5 • « Figure 49. Rock-Eval logs for the Gold Creek well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm CQr defines a oil and^s source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samples arepredominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 174 NADU RIVER WELL TMAX ORGANIC MATURATION (°C) 300 400 500 o o CN O O o o ID o 3 00 0_ Ul O Q O o o o CM. O o: o o: (0 o o: CO QOM QUAUTY OF ORGANIC MATTER (mg HC/g ROCK) 0 2 4 6 8 10 HI HYDROGEN INDEX (mg HC/g ROCK) 0 150 300 450 600 • to * PI PRODUCTION INDEX (S1/S1+S2) 0 0.5 1 -J i—i i i i i i i i Figure 50. Rock-Eval logs for the Nadu River well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm C defines a oil and gas source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 175 PORT LOUIS WELL TMAX QOM HI PI 3( O-ORGANIC MATURATION (°C) 30 400 500 • i • i i • i i i i ( QUALITY OF ORGANIC MATTER (mg HC/g ROCK) 3 2 4 6 8 10 HYDROGEN INDEX (mg HC/g ROCK) 3 150 300 450 600 PRODUCTION INDEX (S1/S1+S2) 0 0.5 1 • * o= J • i CM; i o' ! j i to; i O- i 2 BO; _ j x : 1— H 0. • ui o-O O * > o. 1 I I 'i •• •• / CM. • ; • • • •* • • • • » • • «i o-IO. • o-o: m i Figure 51. Rock-Eval logs for the Port Louis well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm C defines a oil and gas source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samples are'predominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 176 TLELL WELL TMAX ORGANIC MATURATION (°C) 300 400 500 —i i i i • • • • • o o CS" 6: o-o o CO o ^ o Q. LU O a o o. o o cs o o: •4-. o o: IO. o o: CD QOM QUAUTY OF ORGANIC MATTER (mg HC/g ROCK) 0 2 4 6 8 10 -i i i i i i • • • i HI HYDROGEN INDEX (mg HC/g ROCK) 0 150 300 450 600 • • • • 9 PI PRODUCTION INDEX (S1/S1+S2) 0.5 1 —i—i i i i i i i Figure 52. Rock-Eval logs for the Tlell well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm CQrg defines a gas source, HI from 150-300 mg HC/gm CQr defines a oil and gas source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samplesfre predominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 177 TOW HILL WELL TMAX ORGANIC MATURATION (°C) 300 400 500 QOM QUALITY OF ORGANIC MATTER (mg HC/g ROCK) 0 2 4 6 8 10 O; • 1 1 • - • j 1 1 1 : • 1 1 1 1 1 1 O- • ; j o-• • - j • • •• • •; • • O- i O- • • J , J • •; : • • >• •• p. O-O- • • j to- j j • • ; » • • ! ! • • • •• • < * • • : • • • • 2 oo: • ! ; ^ «. •: •: » » *> I • • I— • • Q_ UJ o- • o o: • • O. j j it • • » • • • • o • • t; o: CN. •< • • < »: j j • :*J • • ! * • • •: ! i* • • • o: • » • • • • • • • • • • • i» o-o: » « j us. • * i • ; ! « • • »! o- | ; i o: EO : : HI HYDROGEN INDEX (mg HC/g ROCK) 0 150 300 450 600 PI PRODUCTION INDEX (S1/S1+S2) 0.5 1 Figure 53. Rock-Eval logs for the Tow Hill well which penetrates Tertiary Skonun Formation strata on Graham Island. Tmax, HI, and PI are standard Rock-Eval parameters (Espitalie et al., 1977), QOM = (SI + S2)/TOC. 430 (435) °C to 465 °C T defines the oil window. HI from 0-150 mg HC/gm C defines a gas source, HI from 150-300 mg HC/gm CQr defines a oil and^as source, HI from 300+ defines an oil source. PI values between 0.1 and 0.4 define the oil window. Samples are predominantly coal and lignite with minor siltstone/sandstone from cuttings and core. 178 1 1 132° MEAN TOTAL ORGANIC CARBON (TOC) Figure 54. Regional distribution of the mean TOC content for the Skonun Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. 179 MEAN TOTAL ORGANIC CARBON (TOC) HONNA FORMATION Figure 55. Regional distribution of the mean TOC content for the Honna Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Value in brackets are mean vitrinite reflectance values. Dashed values are minimum and maximum vitrinite reflectance values. 180 132" MEAN TOTAL ORGANIC CARBON (TOC) SKIDEGATE FORMATION Figure 56. Regional distribution of the mean TOC content for the Skidegate Formation. Values are mean TOC calculated a. the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 181 -i • 1 132° MEAN TOTAL ORGANIC CARBON (TOC) HAIDA FORMATION Figure 57. Regional distribution of the mean TOC content for the Haida Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Figure 58. Regional distribution of the mean TOC content for the Longarm Formation. Values are mean TOC calculated ac the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 183 132° MEAN TOTAL ORGANIC CARBON (TOC) YAKOUN & MORESBY GROUPS Figure 59. Regional distribution of the mean TOC content for the Yakoun and Moresby Groups. Values are mean TOC calculated across the thickness of the formation at each outcrop location. 184 1 132° MEAN TOTAL ORGANIC CARBON (TOC) MAUDE GROUP Figure 60. Regional distribution of the mean TOC content for the Maude Group. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 185 132° MEAN TOTAL ORGANIC CARBON (TOC) Figure 61. Regional distribution of the mean TOC content for the Phantom Creek Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. 186 -i 132° MEAN TOTAL ORGANIC CARBON (TOC) WHITEAVES FORMATION Figure 62. Regional distribution of the mean TOC content for the Whiteaves Formation. Values are mean TOC calculated a the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. ! 132° MEAN TOTAL ORGANIC CARBON (TOC) FANNIN FORMATION 187 Figure 63. Regional distribution of the mean TOC content for the Fannin Formation. Values are mean TOC calculated thickness of the formation at each outcrop location. 188 l 1 132° MEAN TOTAL ORGANIC CARBON (TOC) Figure 64. Regional distribution of the mean TOC content for the Rennell Formation. Values are mean TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 189 MEAN TOTAL ORGANIC CARBON (TOC) GHOST CREEK & SANDILANDS FORMATIONS 132° 131° -J I— Figure 65. Regional distribution of the mean TOC content for the Ghost Creek and Sandilands Formations. Values are average TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing TOC. 190 1 1 132° MEAN TOTAL ORGANIC CARBON (TOC) GHOST CREEK FORMATION Figure 66. Regional distribution of the average TOC content for the Ghost Creek Formation. Values are average TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 191 MEAN TOTAL ORGANIC CARBON (TOC) SANDILANDS FORMATION 132° 131° Figure 67. Regional distribution of the average TOC content for the Sandilands Formation. Values are average TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. Tick marks on contour indicate decreasing TOC. 192 MEAN TOTAL ORGANIC CARBON (TOC) BLACK LIMESTONE MEMBER (KUNGA GROUP) /3 132° 131° I I 1 Figure 68. Regional distribution of the average TOC content for the black limestone member (Kunga Group). Values are average TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. Labelled values do not fit regional trends and are not contoured. 193 MEAN TOTAL ORGANIC CARBON (TOC) GREY LIMESTONE MEMBER (KUNGA GROUP) MORESBY ISLAND 10 _l_ 20 I 30km _J r-52 —r-131° 1^2 Figure 69. Regional distribution of the average TOC content for the grey limestone member (Kunga Group). Values are average TOC calculated across the thickness of the formation at each outcrop location. Dashed line represents an inferred contour. 132° QUALITY OF ORGANIC MATTER (S1+S2\ v TOC I SKONUN FORMATION Figure 70. Regional distribution of the average QOM [(SI + S2)/TOC] for the Skonun Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. 195 -l 1 132° Figure 71. Regional distribution of the average QOM [(SI + S2)/TOC] for the Honna Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Values in brackets are mean QOM. Dashed values are minimum and maximum QOM. 1 96 I— 132° Figure 72. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Skidegate Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. 197 132° Figure 73. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Haida Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Figure 74. Regional distribution of the average QOM [(SI + S2)/TOC] for the Longarm Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. 199 -1— 132° Figure 75. Regional distribution of the average QOM [(SI + S2)/TOC] for the Yakoun and Moresby Groups. Values are average QOM calculated across the thickness of the formation at each outcrop location. 200 -1 1 132° Figure 76. Regional distribution of the average QOM [(SI + S2)/TOC] for the Maude Group. Values are average QOM calculated across the thickness of the formation at each outcrop location. Tick marks on contour line indicate decreasing QOM. -1— 132° Figure 77. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Phantom Creek Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. 202 132° QUALITY OF ORGANIC MATTER WHITEAVES FORMATION . S1+S2 v V TOC I Figure 78. Regional distribution of the average QOM [(SI + S2)/TOC] for the Whiteaves Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. 203 Figure 79. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Fannin Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. 204 -1 1 132° Figure 80. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Rennell Junction Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. 205 QUALITY OF ORGANIC MATTER (S^|2) SANDILANDS & GHOST CREEK FORMATIONS Figure 81. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Sandilands and Ghost Creek Formations. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM. 206 l 132" QUALITY OF ORGANIC MATTER /S1+S2 \ I TOC ' GHOST CREEK FORMATION Figure 82. Regional distribution of the average QOM [(Sl + S2)/TOC] for the Ghost Creek Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM. 207 QUALITY OF ORGANIC MATTER /S1+S2 SANDILANDS FORMATION ' T0C 132° 131° _l I Figure 83. Regional distribution of the average QOM [(SI + S2)/TOC] for the Sandilands Formation. Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. Tick mark on contour line indicates decreasing QOM. 208 Figure 84. Regional distribution of the average QOM [(SI + S2)/TOC] for the black limestone member (Kunga Group). Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. 209 T 0 132° » I I I Figure 85. Regional distribution of the average QOM [(SI + S2)/TOC] for the grey limestone member (Kunga Group). Values are average QOM calculated across the thickness of the formation at each outcrop location. Dashed line represents inferred contour. Labelled values do not fit regional trends and are not contoured. 210 hydrocarbon generation (see Part I). Mesozoic strata on Morseby Island south of Cumshewa Inlet are overmature and the DOM increases proximal to Jurassic-Cretaceous plutonic suites. The regional level of organic maturation of Triassic and Cretaceous strata on northwest Graham Island ranges from immature to mature with local, anomalous overmature strata. Jurassic and Cretaceous strata on central Graham Island are marginally mature to mature, whereas in the Skidegate and Cumshewa Inlet areas the strata are mature to overmature. DISCUSSION The following section documents the hydrocarbon source potential for selected Mesozoic and Tertiary strata. Geochemical parameters from Rock-Eval pyrolysis describing organic maturation, hydrocarbon generative potential, and type of generated hydrocarbons are outlined in Table 5. Tmax values are not reported in Table 6 for samples with S2 values lower than the minimum 0.2 mg HC/gm CQrg considered necessary for accurate ^max determination (Peters, 1986). In very overmature samples, the HI and OI values are too low to ascertain the type of original organic matter. KUNGA GROUP Grey Limestone Member Low QOM (<0.08 mg HC/gm CQrg), low HI (<8 mg HC/gm CQrg), low PI (<0.08) and high maturation (2.35 to 5.28 %R°ran(i) vames indicate that the massive carbonates of the grey limestone member exposed on Moresby Island have poor oil source potential but are possibly gas source rocks. Some residual organic carbon (<1.1 % TOC), and low PI values (<0.08) from south Moresby Island suggest hydrogen depletion and that the strata may have been source rocks and previously generated hydrocarbons. High maturation values preclude the determination of the initial type of organic matter (Figure 47R). 211 SURFACE MATURATION MAP FOR MESOZOIC AND TERTIARY STRATA Figure 86. Surface maturation trends for Mesozoic and Tertiary strata derived from vitrinite reflectance data (%Ro -see Part I). Oil window is between 0.50 %Ro J and 1.35 %Ro rand rand 212 TABLE 5 GEOCHEMICAL PARAMETERS DESCRIBING LEVEL OF THERMAL MATURATION MATURATION PI S1/(S1+S2) Tmax (°C) Ro (%) TOP OF OIL WINDOW 0.1 BOTTOM OF OIL WINDOW 0.4 C« v Maturation parameter may depend on type of organic matter) 430-435 465 0.5 1.35 GEOCHEMICAL PARAMETERS DESCRIBING SOURCE ROCK GENERATIVE POTENTIAL QUANTITY TOC (weight %) SI (mg HC/gm CQrg) S2 (mg HC/gm CQrg) POOR FAIR GOOD VERY GOOD 0.0-0.5 03-1.0 1.0-2.0 2 + 0.0-0.5 03-1.0 1.0-2.0 2 + 0.0-2.5 25-5.0 5.0-10.0 10 + GEOCHEMICAL PARAMETERS DESCRIBING TYPE OF HYDROCARBON GENERATED TYPE HI (mg HC/gm CQrg)* S2/S3 GAS GAS AND OIL OIL 0-150 150-300 300 + 0-3 3-5 5 + ( Assumes a DOM equivalent to RQ = 0.6%) 213 ***** * * TABLE 6A GREY LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %R°rand Tmx TOC S1 S2 PI QOM HI 01 OF SECTION BB MEAN 5.8 * • • # OF SAMPLES 3. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION Bl MEAN ».««».,,, # OF SAMPLES 0. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BJ MEAN 2.35 # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BR MEAN 2.72 ..... # OF SAMPLES 4. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CB MEAN g ....... . # OF SAMPLES 2. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CRE MEAN 459 ........ # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HP MEAN 2.61 ........ # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HU MEAN 2.91 ........ # OF SAMPLES 8. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION JED MEAN 656 • # OF SAMPLES 3. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION KT MEAN 4.39 * • # OF SAMPLES 10. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION TB MEAN 4.38 ....... # OF SAMPLES 4. 0. 0. 0. 0. 0. 0. 0. 0. 214 TABLE 6A (CONT.) GREY LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Ro . TMAX TOC SI S2 PI QOM HI Ol rand OF SECTION TIT MEAN 5.28 ........ # OF SAMPLES 1. 0. 0. 0. 0. 0. 0. 0. 0. SECTION 1 MEAN • • 1.1 0.01 0.03 0.08 0.02 2. 35. # OF SAMPLES 0. 0. 3. 3. 3. 3. 3. 3. 3. SECTION 3 MEAN • * 0.18 0. 0. 0. 0. 0. 33. # OF SAMPLES 0. 0. 1. 1. 1. 1. 1. 1. 1. SECTION 6 MEAN • * 0.06 0. 0. 0. 0. 0. 48. # OF SAMPLES 0. 0. 6. 6. 6. 6. 6. 6. 6. SECTION 7 MEAN • * 0.28 0. 0. 0. 0.01 0. 26. # OF SAMPLES 0. 0. 4. 4. 4. 4. 4. 4. 4. SECTION 8 MEAN * * 0.24 0. 0.02 0. 0.08 8. 24. # OF SAMPLES 0. 0. 4. 4. 4. 4. 4. 4. 4. SECTION 9 MEAN • • 0.06 0. 0. 0. 0. 0. 0. # OF SAMPLES 0. 0. 1. 1. 1. 1. 1. 1. 1. SECTION 10 MEAN * • 0.06 0. 0. 0. 0. 0. 0. #OFSAMPLES 0. 0. 1. 1. 1. 1. 1. 1. 1. SPOT SAMPLE MEAN * • 0.10 0. 0. 0. 0. 0. 132. # OF SAMPLES 0. 0. 5. 5. 5. 5. 5. 5. 5. TF SPOT SAMPLE MEAN 2.95 •• 0. 0. 0. 0. * 0. 0. # OF SAMPLES 3. 0. 3. 3. 3. 3. 0. 3. 3. 215 TABLE 6B BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand ™AX TOC S1 S2 PI QOM HI 01 OF SECTION Bl MEAN # OF SAMPLES 4.56 28. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION BJ MEAN # OF SAMPLES 4.09 10. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CB MEAN # OF SAMPLES 8.31 * * * * 1. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION CRE MEAN # OF SAMPLES 4.59 1. 0. 0. 0. 0. 0. OF SECTION DP MEAN # OF SAMPLES 4.84 2. 0. 0. 0. 0. 0. 0. 0. OF SECTION EPO MEAN # OF SAMPLES 4.81 1. 0. 0. 0. 0. 0. 0. OF SECTION FUN MEAN # OF SAMPLES 5.05 2. 0. 0. 0. 0. 0. 0. OF SECTION GB MEAN # OF SAMPLES 3.13 2. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HO MEAN # OF SAMPLES 5.08 9. 0. 0. 0. 0. OF SECTION HP MEAN # OF SAMPLES 2.94 5. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION HUX MEAN # OF SAMPLES 4.33 19. 0. 0. 0. 0. 0. 0. 216 TABLE 6B (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM HI 01 OF SECTION JED MEAN # OF SAMPLES 4.23 1. 0. 0. 0. 0. 0. 0. 0. OF SECTION KT MEAN # OF SAMPLES 4.66 18. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION KU MEAN # OF SAMPLES 4.56 12. 0. 0. 0. 0. 0. 0. 0. 0. OF SECTION LUX MEAN # OF SAMPLES 4.63 1. 0. 0. 0. 0. 0. OF SECTION NPO MEAN # OF SAMPLES 4.62 3. 0. 0. 0. 0. 0. 0. 0. OF SECTION POO MEAN # OF SAMPLES 353 5. 0. 0. 0. 0. OF SECTION RH MEAN # OF SAMPLES 5.6 2. 0. 0. 0. 0. 0. 0. OF SECTION RI MEAN # OF SAMPLES 4.37 6. 0. 0. 0. 0. 0. OF SECTION ROSS MEAN # OF SAMPLES 4.87 2. 0. 0. 0. 0. OF SECTION SC MEAN # OF SAMPLES 4.35 5. 0. 0. 0. 0. OF SECTION SHU MEAN # OF SAMPLES 2.4 6. 0. 0. 0. 0. 0. 0. 0. 217 TABLE 6B (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %R°rand TOC S1 S2 PI QOM HI 01 OF SECTION SI MEAN # OF SAMPLES 4.1 4. 0. 0. 0. 0. OF SECTION SK MEAN # OF SAMPLES 3.78 3. 0. 0. OF SECTION SKU MEAN # OF SAMPLES 4.58 13. 0. 0. 0. 0. 0. 0. OF SECTION SPO MEAN # OF SAMPLES 3.89 1. 0. 0. OF SECTION TB MEAN # OF SAMPLES 2.37 1. 0. 0. 0. 0. OF SECTION VP MEAN # OF SAMPLES 3.85 1. 0. 0. 0. 0. 0. SECTION 1 MEAN # OF SAMPLES 0. 0. 0.82 8. 0.01 8. 0. 32. SECTION 2 MEAN # OF SAMPLES 0. 0. 0.9 5. 0.01 5. 231. 5. SECTION 3 MEAN # OF SAMPLES 0. 0. 1.02 0. 8. 8. 0.01 1. 13. SECTION 4 MEAN # OF SAMPLES 3.64 3. 2.21 4. 0.05 4. 0.03 4. 0.05 4. 16. 4. 13. 4. SECTION 7 MEAN # OF SAMPLES 0. 0. 0.41 3. 218 TABLE 6B (CONT.) BLACK LIMESTONE MEMBER (KUNGA GROUP) SECTION NAME %R°rand ™AX TOC S1 S2 PI QOM HI 01 SECTION 8 MEAN # OF SAMPLES 0.25 5. 0. 5. 0. 5. 0.02 5. 0. 5. 50. 5. SECTION 9 MEAN # OF SAMPLES 0.22 9. 0. 9. 0. 9. 0.01 9. 1. 9. SECTION 10 MEAN # OF SAMPLES 4.29 14. 1.16 0. 0.01 0.07 0.01 1. 24. 15. 15. 15. 15. 15. 15. 15. SECTION 11 MEAN # OF SAMPLES 5.11 1. 2.56 1. 0.07 1. 0.01 1. 0.87 1. 0.03 1. 11. 1. SECTION 12 MEAN # OF SAMPLES 0.51 440. 6. 6. 3.6 6. 1.21 6. 14.08 6. 0.08 6. 4.19 6. 385. 6. SECTION 13 MEAN # OF SAMPLES 3.19 587. 2.9 0.04 0.08 0.33 0.04 2. 24. 16. 1. 18. 18. 18. 18. 18. 18. 18. SECTION 14 MEAN # OF SAMPLES 1.59 2. 0. 0. 0. 0. 0. 0. 0. 0. SECTION IS MEAN # OF SAMPLES 1.47 467. 2. 1. 2.69 0.64 0.83 1. 1. 1. 0. 44 0.55 30. 47. 1. 1. 1. 1. SECTION 19 MEAN # OF SAMPLES 1.18 444. 16. 18. 2.17 18. 0.57 18. 4.69 18. 0.12 18. 2.19 17. 192. 18. 14. 18. SPOT SAMPLE MEAN # OF SAMPLES 4.04 30. 0. 1.06 38. 0. 38. 0.01 38. 0.04 38. 0.02 38. 0. 38. 25. 38. 219 TABLE 6C SANDILANDS FORMATION SECTION NAME %Rorand ™AX TOC sl S2 PI °-OM HI 01 SECTION 5 MEAN # OF SAMPLES 0.51 4. 0.01 4. 0.03 4. 0.06 4. 0.03 4. 49. 4. SECTION 11 MEAN # OF SAMPLES 3.78 18. 133 21. 0.04 21. 0.03 21. 0.59 21. 0.05 21. 2. 21. 9. 21. SECTION 12 MEAN # OF SAMPLES 0.45 436. 18. 10. 2.66 10. 0.77 10. 12.9 10. 0.06 10. 4.66 10. 437. 10. 10. 10. SPOT SAMPLE MEAN # OF SAMPLES 4. 5. 059 8. 0. 8. 0. 8. 0.01 0. 8. 8. CENTRAL GRAHAM ISLAND B-QUARRY MEAN # OF SAMPLES 0.40 443. 17. 17. 3.14 17. 1.64 17. 13.85 17. 0.14 17. 4.26 17. 372. 17. 36. 17. CENTRAL GRAHAM ISLAND D-QUARRY MEAN # OF SAMPLES 0.66 447. 4. 4. 1.32 5. 0.67 5. 3.83 5. 0.16 4. 2.73 5. 229. 5. 525. 5. CENTRAL GRAHAM ISLAND BRANCH ROAD 57 MEAN # OF SAMPLES 0.65 437. 6. 6. 1.25 6. 0.47 6. 3.43 6. 0.16 6. 3.32 6. 264. 6. 42. 6. CENTRAL GRAHAM ISLAND MAIN ROAD MEAN # OF SAMPLES 0.60 445. 4. 4. 2.08 5. 1.02 5. 4.9 5. 0.15 5. 1.94 5. 159. 5. 68. 5. CENTRAL GRAHAM ISLAND WELL 1-178 MEAN # OF SAMPLES 0.60 437. 32. 32. 1.75 33. 1.12 33. 3.86 33. 0.25 33. 2.75 33. 210. 33. 48. 33. CENTRAL GRAHAM ISLAND WELL 1-179 MEAN # OF SAMPLES 0.88 447. 40. 37. 9.6 40. 0.50 40. 4.12 40. 0.31 38. 2.71 39. 242. 39. 73. 39. 220 TABLE 6C (CONT.) SANDILANDS FORMATION SECTION NAME %Ro . TMAX TOC rand SI S2 PI QOM HI Ol CENTRAL GRAHAM ISLAND WELL 1-278 MEAN # OF SAMPLES 0.65 447. 1.91 0.99 4.60 0.23 2.56 205. 57. 47. 47. 47. 47. 47. 47. 47. 47. 47. MAUDE ISLAND MEAN # OF SAMPLES 1.35 465. 8. 8. 1.47 9. 0.24 9. 0.52 9. 0.42 9. 0.44 9. 27. 9. 34. 9. RENNELL SOUND MEAN # OF SAMPLES 157 479. 32. 32. 1.47 33. 0.15 33. 0.3 33. 0.40 33. 0.32 33. 17. 33. 18. 33. SHIELDS BAY MEAN # OF SAMPLES 1.27 7. 0. 057 7. 0.06 7. 0.0 7. 1.0 7. 0.09 7. 0.0 7. 221 TABLE 6D GHOST CREEK FORMATION SECTION NAME %Ro . TMAX TOC rand SI S2 PI QOM HI OI BC SECTION 10 MEAN # OF SAMPLES 0.55 448. 3. 4. 1.66 4. 0.39 4. 5.11 4. 0.08 4. 3.19 4. 218. 4. 13. 4. BC SECTION 4 MEAN # OF SAMPLES 1.32 486. 1. 1. 0.68 1. 0.07 1. 0.25 1. 0.22 1. 0.47 1. 36. 1. 29. 1. BC SECTION 7 MEAN # OF SAMPLES 1.51 470. 2. 2. 1.63 2. 0.43 2. 0.63 2. 0.41 7 0.65 2. 38. 2. 17. 2. BC SECTION 8 MEAN # OF SAMPLES IS 480. 4. 4. 1.84 4. 0.44 4. 0.7 4. 0.41 4. 0.66 4. 38. 4. 15. 4. BC SECTION CAA-86-2 MEAN # OF SAMPLES 0.88 454. 1.27 0.43 1.98 0.17 1.73 141. 32. 6. 4. 5. 5. 5. 5. 5. 5. 5. CENTRAL GRAHAM ISLAND A-QUARRY MEAN # OF SAMPLES 050 438. 1. 1. 0.6 1. 1.46 1. 1.76 1. 0.45 1. 5.37 1. 293. 1. 108. 1. MAUDE ISLAND MEAN # OF SAMPLES 1.38 442. 5. 5. 1.90 5. 0.55 5. 4.66 5. 0.10 5. 2.43 5. 209. 5. 105. 5. RENNELL SOUND MEAN # OF SAMPLES 1.57 477. 0.79 0.05 0.09 0.48 0.14 9. 106. 7. 7. 7. 7. 7. 7. 7. 7. 7. CENTRAL GRAHAM ISLAND WELL 1-179 MEAN # OF SAMPLES 0.88 444. 36. 36. 1.73 36. 0.36 36. 6.64 36. 0.07 33. 3.73 34. 349. 34. 76. 34. WHITEAVES BAY MEAN # OF SAMPLES 1.35 448. 6. 6. 1.6 6. 0.46 6. 0.60 6. 0.49 6. 0.62 6. 32. 6. 222 TABLE 6E RENNELL JUNCTION FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM HI 01 BC SECTION 10 MEAN 052 445. 0.71 0.25 1.27 0.16 2.14 178. 46. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION 4 MEAN 1.17 467. 058 0.05 0.16 0.12 0.33 28. 288. # OF SAMPLES 2. 1. 2. 2. 2. 2. 2. 2. 2. BC SECTION 7 MEAN 15 488. 157 0.27 0.35 0.44 0.39 22. 8. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION 8 MEAN 1.45 471. 1.96 0.4 0.59 0.41 0.51 30. 21. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. BC SECTION CAA-86-2 MEAN 0.88 458. 1.07 0.05 0.3 0.14 0.84 93. 78. # OF SAMPLES 3. 4. 4. 4. 4. 4. 4. 4. 4. 223 TABLE 6F FANNIN FORMATION SECTION NAME %Rorand ™AX TOC sl S2 PI °-OM HI 01 BC SECTION 4 MEAN # OF SAMPLES 1.31 2. 0.18 0.01 0.01 0.25 0.13 8. 74. 2. 2. 2. 2. 2. 2. 2. BC SECTION 7 MEAN # OF SAMPLES 1.45 3. 0. 0.23 3. 0.02 3. 0.05 3. 0.22 3. 0.31 3. 25. 3. 27. 3. BC SECTION 8 MEAN # OF SAMPLES 1.47 ' 0.26 0.03 0.09 0.24 0.53 42. 88. 3. 0. 3. 3. 3. 3. 3. 3. 3. BC SECTION 8 MEAN # OF SAMPLES 151 * 0.28 0.02 0.08 0.2 0.34 28. 136. 5. 0. 5. 5. 5. 5. 5. 5. 5. BC SECTION CAA-86-2 MEAN # OF SAMPLES 0.85 2. NORTH MORESBY MEAN # OF SAMPLES (*Ro ) v max7 1.42 1. 224 TABLE 6G WHITEAVES FORMATION SECTION NAME %Rorand ™AX TOC sl S2 PI QOM HI 01 BC SECTION 10 MEAN # OF SAMPLES 0.64 448. 5. 1. 0.18 5. 0.01 5. 0.10 5. 0.03 5. 0.62 5. 60. 5. 51. 5. BC SECTION 11 MEAN # OF SAMPLES 0.43 440 5. 1. 0.33 5. 0.01 5. 0.18 5. 0.07 5. 0.62 5. 57. 5. BC SECTION 12 MEAN # OF SAMPLES 0.46 442. 2. 1. 5.27 2. 0.02 2. 0.24 2. 0.09 0.43 2. 14. BC SECTION 14 MEAN # OF SAMPLES 0.78 4. 0. 0.26 4. 0.01 4. 0.11 4. 0.11 4. 0.47 42. 4. 4. 10. 4. BC SECTION 15 MEAN # OF SAMPLES 0.63 440. 5. 4. 059 5. 0.04 5. 0.36 5. 0.11 5. 0.65 5. 58. 5. BC SECTION 4 MEAN # OF SAMPLES 1.26 3. 0. 0.23 3. 0. 3. 0.01 3. 0.17 3. 0.07 3. 125. 3. BC SECTION 5 MEAN # OF SAMPLES 15 4. 0.34 3. 0.01 3. 0.05 3. 0.26 3. 0.18 3. 14. 3. BC SECTION 6 MEAN # OF SAMPLES 1.49 3. 0.27 4. 0. 4. 0.02 4. 0.13 4. 0.08 4. 54. 4. BC SECTION 7 MEAN # OF SAMPLES 1.42 3. 0. 0.32 3. 0.02 3. 0.08 3. 0.2 3. 0.32, 3. 25. 3. 18. 3. BC SECTION CAA-86-2 MEAN # OF SAMPLES 0.82 464. 2. 2. 1.8 2. 0.16 2. 1.13 2. 0.13 2. 0.73 2. 64. 2. 16. 7 NORTH MORESBY MEAN SAMPLES (*Ro ) v max' 1.51 1. # OF 225 TABLE 6H PHANTOM CREEK FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI QOM HI 01 BC SECTION 12 MEAN 0.46 440. 055 0.38 1.85 0.16 3.9 322. 10. # OF SAMPLES 4. 4. 4. 4. 4. 4. 4. 4. 4. 226 TABLE 61 GRAHAM ISLAND FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI QOM HI OI BC SECTION 10 MEAN # OF SAMPLES 0.48 446. 8. 5. 0.96 8. 0.08 8. 157 8. 0.06 1.17 111. 86. BC SECTION 14 MEAN # OF SAMPLES 0.77 443. 6. 4. 0.88 7. 0.14 7. 2.22 7. 0.23 7. 1.94 7. 127. 7. 14. 7. BC SECTION 6 MEAN # OF SAMPLES 1.5 3. 0.34 3. 0.01 3. 0.08 3. 0.26 24. 3. 3. 43. 3. TABLE 6J RICHARDSON BAY FORMATION SECTION NAME %Ro , TMAX TOC SI S2 PI rand BC SECTION 16 MEAN 1.13 396. 1.13 0.20 052 0.28 # OF SAMPLES 6. 6. 6. 6. 6. 6. 228 TABLE 6K ROBBER POINT FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM HI OI BC SECTION 16 MEAN 1.10 468. 0.78 0.14 0.35 0.29 0.63 44. 15. # OF SAMPLES 1. 1. 1. 1. 1. 1. 1. 1. 1. TABLE 6L NEWCOMBE FORMATION SECTION NAME %Rorand TMAX TOC SI S2 PI QOM BC SECTION 17 MEAN 1.08 * 051 0.02 0.15 0.12 0.: # OF SAMPLES 3. 0. 3. 3. 3. 3. 3. 230 TABLE 6M ALLIFORD FORMATION SECTION NAME %Ro , TMAX TOC rand SI S2 PI QOM HI OI BC SECTION 16 MEAN # OF SAMPLES 1.04 320. 1.10 0.22 0.89 0.20 1.01 80. 13. 3. 3. 3. 3. 3. 3. 3. 3. 3. TABLE 6N LONGARM FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI Q-OM SPOT SAMPLE MEAN 3.18 ' 0.26 0. 0. 0.03 0.03 # OF SAMPLES 20. 0. 33. 33. 33. 33. 33. NORTH MORESBY MEAN 2.07* ...... # OF SAMPLES 5. (*Ro ) v max7 232 TABLE 60 HAIDA FORMATION SECTION NAME %R°rand ™AX TOC S1 S2 PI QOM HI OI BC SECTION CAA-86-1 MEAN # OF SAMPLES 0.98 701. 26. 17. 0.68 26. 0.05 26. 0.36 26. 0.1 26. 0.56 49. 26. 26. 5. 26. BC SECTION CAA-86-5 MEAN # OF SAMPLES 0.36 439. 0.73 0.01 0.48 0.02 0.67 65. 29. 10. 10. 11. 11. 11. 11. 11. 11. ii. SECTION 14 MEAN # OF SAMPLES 1.51 504. 8. 2. 2.23 3. 0.35 3. 0.74 3. 0.27 3. 0.48 3. 34. 3. 36. 3. SECTION IS MEAN # OF SAMPLES 0.77 449. 40. 2. 2.49 2. 0.07 2. 0.9 2. 0.43 •> 39. 7 50. •> SECTION 17 MEAN # OF SAMPLES 0.68 11. 0. 0. SECTION 18 MEAN # OF SAMPLES 0.43 14. 0. 0. 0. SPOT SAMPLE MEAN # OF SAMPLES 4.04 3. 0.13 7. 0.14 0.02 7. 7. 0. 33. 7. 7. NORTH MORESBY MEAN # OF SAMPLES (*Ro ) v max' 1.13 2. TABLE 6P SKIDEGATE FORMATION SECTION NAME %Ro . TMAX TOC SI S2 rand SECTION 20 MEAN 1.91 497. 0.6 0.01 0.08 # OF SAMPLES 14. 1. 11. 11. 11. BC SECTION CAA-86-3 MEAN 0.96 433. 0.26 0.03 0.18 # OF SAMPLES 35. 11. 32. 32. 32. BC SECTION CAA-86-4 MEAN ..... # OF SAMPLES 0. 0. 0. 0. 0. BC SECTION CAA-86-6 MEAN 0.4 439. 0.73 0.02 054 # OF SAMPLES 23. 25. 25. 25. 25. BC SECTION CAA-86-T-3 MEAN 1.09 464. 0.17 0.01 0.10 # OF SAMPLES 7. 2. 7. 7. 7. BC SECTION CAA-86-T4 MEAN 0.47 437. 0.43 0. 0.19 # OF SAMPLES 8. 2. 5. 5. 5. BC SPOT SAMPLE MEAN 1.8 470. 0.51 0.02 0.18 # OF SAMPLES 66. 10. 53. 53. 53. SECTION 16 MEAN 0.71 442. 0.3 0.01 0.19 # OF SAMPLES 10. 2. 8. 8. 8. SECTION 21 MEAN 1.39 456. 0.32 0.02 0.12 # OF SAMPLES 11. 1. 10. 10. 10. SECTION 22 MEAN 0.87 436. 0.63 0. 0.17 # OF SAMPLES 3. 1. 2. 2. 2. SPOT SAMPLE MEAN 2.94 * 0.13 0. 0.02 # OF SAMPLES 3. 0. 4. 4. 4. TABLE 6Q HONNA FORMATION SECTION NAME %Rorand ™AX TOC S1 S2 PI °-OM SECTION 22 MEAN 1.14 436. 0.43 0.03 0.24 0.09 0.7 # OF SAMPLES 16. 7. 12. 12. 12. 12. 12. SPOT SAMPLE MEAN ' * 0.08 0. 0. 0. 0. # OF SAMPLES 0. 0. 1. 1. 1. 1. 1. NORTH MORESBY MEAN 0.80* ...... # OF SAMPLES 4 ..... . (*Ro ) v max' 235 TABLE 6R SKONUN FORMATION SECTION NAME %Rorand f™** TOC S1 S2 PI QOM HI 01 CAPE BALL WELL MEAN # OF SAMPLES 0.32 403. 22. 16. 41.68 16. 16.3 16. 81.42 16. 0.15 16. 2.2 16. 179. 16. 38. 16. GOLD CREEK WELL MEAN # OF SAMPLES 0.27 418. 7. 4. 24.44 4. 0.97 4. 14.42 4. 0.08 4. 0.70 4. 64. 4. 68. 4. LOG CREEK MEAN # OF SAMPLES 0. 39 420. 2.47 1.32 5.2 0.2 2.64 210. 14. 1. 1. 1. 1. 1. 1. 1. 1. 1. MILLER CREEK MEAN # OF SAMPLES 0.19 1. 0. 0. 0. 0. 0. 0. NADU RIVER WELL MEAN # OF SAMPLES PORT LOUIS WELL MEAN # OF SAMPLES 0.29 400. 10. 4. 1.05 486. 24. 13. 6.67 8. 10.45 14. 1.36 7.72 0.46 0.9 64 0.73 14. 10.3 14. 0.07 14. 0.87 14. 199 8. 9. 14. TLELL WELL MEAN # OF SAMPLES 0.27 417. 17. 14. 22.88 15. 7.27 15. 39.12 15. 0.15 15. 1.91 15. 161. 15. 74. 15. TOW HILL WELL MEAN # OF SAMPLES 0.48 430. 45. 36. 36.18 40. 7.17 40. 31.76 40. 0.17 40. 1.19 40. 93. 40. 28. 39. 236 Black Limestone Member High DOM (2.37 to 8.31 %Rorand), and low QOM (<0.05 mg HC/gm Corg), PI (0.03 to 0.07), and HI (< 16 mg HC/gm CQrg) values for the interbedded shale and calcarenite of the black limestone member exposed on Moresby Island indicate that the strata are presently poor oil source rocks. Low PI, high DOM, low HI, and variable TOC (< 2.56 %) values suggest hydrocarbon depletion and indicate that hydrocarbons may have been previously generated. Moderate amounts of residual carbon (< 2.56 % TOC) and low HI values suggest some gas generation potential. Mature to overmature strata (0.51 to 3.19 %Rofand; 440 °C to 587 °C ^max) from northwest Graham Island are good oil and gas source rocks as is evident from high TOC (2.17 % to 3.6 %), QOM (<4.19 mg HC/gm CQrg), moderate to high HI (192 to 385 mg HC/gm cQrg), and moderate PI (0.08 to 0.33) values (Tables 5 and 6). Solid bitumen observed in hand specimen accounts for the anomalously high TOC values, and indicates that the strata have previously generated liquid hydrocarbons. Low to moderate PI values in some areas suggest depletion and possible migration of hydrocarbons. The HI/OI diagram for the black limestone member (Figure 47Q) shows two populations of organic matter: Types I and II with high HI and low Ol values with very good oil and gas generative potential from northwest Graham Island; and, overmature Type III with very low HI and high Ol values resulting in fair gas but no oil generative potential at Morseby Island. Sandilands Formation The DOM for the argillites of the Sandilands Formation exposed on Moresby Island is too high (3.78 to 4.00 %Rorand) to consider the strata as oil source rocks. Low QOM (<0.05 mg HC/gm Corg), low HI (<2 mg HC/gm CQrg) and high maturation values (Tables 5 and 6) indicate hydrocarbon depletion suggesting that hydrocarbons may have been previously generated. High PI values (< 0.59) at Kunga Island 237 suggest that hydrocarbons have possibly migrated into overmature strata. Moderate amounts of residual TOC (0.51 to 1.56 %) and low HI values suggest some potential for gas generation. Mature Type I and Type II organic matter of the Sandilands Formation in central Graham Island has good oil and gas source potential as is evident by high TOC (1.25 to 9.6 %), QOM (1.94 to 4.26 mg HC/gm Corg), and moderate to high HI (159 to 372 mg HC/gm CQrg) values (Tables 5 and 6). Moderate PI values (0.14 to 0.42) and free hydrocarbons (SI < 1.64 mg HC/gm CQrg) suggest some conversion of kerogen to petroleum. Marginally immature strata on northwest Graham Island at Kennecott Point are good oil and gas source rocks with high TOC (2.66 %), QOM (4.66 mg HC/gm CQrg), and HI (437 mg HC/gm CQrg) values (Tables 5 and 6). Low PI (0.06) and vitrinite reflectance (0.45 %R°rancj) values suggest a low degree of kerogen conversion to petroleum. The Sandilands Formation at depth is probably more mature and may have generated substantial amounts of petroleum. MAUDE GROUP Ghost Creek Formation Marginally mature (0.55 %R°ranci) strata of the Ghost Creek Formation exposed on central Graham Island and locally in Skidegate Inlet have good oil and gas source potential as indicated by moderate TOC (1.66 to 1.73 %), high QOM (3.19 to 3.73 mg HC/gm Corg), and moderate HI (218.0 to 349 mg HC/gm CQrg) values (Tables 5 and 6). A low PI (0.07) suggest a low degree of kerogen conversion to petroleum. Marginally overmature to overmature strata (1.32 to 1.51 %R°ranci) m Skidegate Inlet (Maude Island) and Rennell Sound are currently poor oil source rocks as suggested by low QOM (0.14 to 0.66 mg 238 HC/gm Corg) and HI (9 to 38 mg HC/gm CQrg). Moderate PI (0.48) values from Rennell Sound suggest that the strata are overmature. Rennell Junction Formation Mature to overmature (0.52 to 1.5 %R°ran(j) sandstone, siltstone, and shale from Cumshewa Inlet and Skidegate Inlet are generally poor source rocks (TOC < 1.96 %; QOM=0.33 mg HC/gm Corg; and HI< 93 mg HC/gm Corg) values. Type III organic matter (Figures 46K and 47N) suggests that the strata are possible gas source rocks. Marginally mature strata in central Graham Island have fair gas source potential as indicated by low TOC (0.71 %), high QOM (2.14 mg HC/gm CQrg), and low HI (178 mg HC/gm CQrg) values (Tables 5 and 6). Fannin Formation Generally overmature (0.85 to 1.51 %R°ranc<) tuffaceous siltstone in central Graham Island and Skidegate Inlet are poor source rocks as indicated by low TOC (<0.28 %), QOM (<0.53 mg HC/gm CQrg), and HI (<42 mg HC/gm CQrg) values (Tables 5 and 6). The HI/OI diagram (Figure 47M) suggests that the Fannin Formation contains terrestrially derived Type III organic matter. Whiteaves Formation Low TOC (<0.59 %), QOM (<0.73 mg HC/gm CQrg) and HI (<60 mg HC/gm CQrg) values (Tables 5 and 6) suggest a poor petroleum source potential for marginally mature to overmature strata (0.43 to 1.5 %R0rancj) on central Graham Island and Skidegate Inlet. Strata in Cumshewa Inlet have some gas source potential (TOC = 1.8 %; QOM = 0.73 mg HC/gm CQrg; PI = 0.13; HI = 64 mg HC/gm CQrg). Very high TOC values (10.28 %) indicate reflect organic rich (Type III) horizons in central Graham Island. 239 Phantom Creek Formation Limited data suggests that the marginally immature (0.46 %R°ranci) fine grained sandstones and shales of the Phantom Creek Formation are poor to fair oil and gas source rocks (TOC = 0.55 %; QOM = 3.9 mg HC/gm Corg; PI = 0.16; and HI= 322 mg HC/gm CQrg). Low PI values suggest partial conversion of kerogen to petroleum (Tables 5 and 6). YAKOUN GROUP Graham Island Formation Marginally mature to overmature (0.48 to 1.5 %Roran(j) shales and siltstones in central Graham Island have low TOC (0.88 to 0.96 %), moderately high QOM (1.17 to 1.94 mg HC/gm Corg), and moderately high HI (< 385 mg HC/gm CQrg) values (Tables 5 and 6) suggesting fair oil and gas source potential. Strata in the Skidegate Inlet area are poor source rocks (TOC = 0.34 %; QOM = 0.26 mg HC/gm Richardson Bay Formation The Richardson Bay Formation consists predominantly of volcanic strata with some sedimentary facies of limited lateral extent. The sedimentary strata contain moderate amounts (1.13 % TOC) of Type III organic matter (HI = 45 mg HC/gm C ). Mature strata (1.13 %Roraa^ in Skidegate Inlet have gas 240 generative potential as suggested by moderate TOC (1.13 %), low QOM (0.63 mg HC/gm cQrg) and low HI (45 mg HC/gm Corg) values (Tables 5 and 6). MORESBY GROUP Robber Point Formation Mature (1.10 %R°rand) coarse elastics in Skidegate Inlet generally have insufficient amounts of organic carbon (0.78 % TOC), low QOM (0.63 mg HC/gm CQrg), and low HI (44 mg HC/gm C0fg) values to be considered hydrocarbon source rocks (Tables 5 and 6). Newcombe Formation Mature, massive volcanic sandstone (1.08 %R°rand) exposed in Skidegate Inlet generally do not have a sufficient TOC (0.51 %) to generate significant amounts of hydrocarbons. Low QOM (0.34 mg HC/gm Corg) and HI (30 mg HC/gm Corg) values suggest poor oil and gas potential (Tables 5 and 6). Alliford Formation 241 Mature (1.04 %Roran(j) siltstones exposed in Skidegate Inlet have fair gas source potential as is indicated by moderate TOC (1.1 %), moderate QOM (1.01 mg HC/gm Corg), and low HI (80 mg HC/gm C ) and PI (0.2) values (Tables 5 and 6). LONGARM FORMATION Low TOC (0.26 %), QOM (0.03 mg HC/gm Corg), HI (5 mg HC/gm CQrg), PI (0.03), and high maturation (3.18 %R°ran(i) values suggest poor oil and gas source potential on Moresby Island (Tables 5 and 6). Data is not available for Graham Island. QUEEN CHARLOTTE GROUP Haida Formation Immature to overmature (0.36 to 1.51 %R°ranrj) carbonaceous sandstones of the Haida Formation, rich in terrestrial organic matter (0.68 to 2.49 % TOC), have fair gas source potential on Graham Island (QOM <0.67 mg HC/gm CQrg; HI <65 mg HC/gm CQrg; and PI < 0.27). Generally overmature (4.04 %Rorancj) strata on Morseby Island have poor oil or gas generative potential (TOC=0.13 %;QOM=0.02 mg HC/gm Corg; and HI = 0 mg HC/gm Corg) but may have previously generated gas pre- or syn- plutonic emplacement in the Cretaceous or Tertiary (see Part I). Skidegate Formation 242 Generally low TOC (<0.73 %) and QOM (<0.95 mg HC/gm CQrg) values suggest that immature to overmature (0.4 to 2.94 %Rorand) Type III (HI <79 mg HC/gm CQrg) organic matter of the Skidegate Formation has poor to fair gas generative potential on Graham Island (Tables 5 and 6). Low PI values (<0.16) for mature strata suggest partial kerogen conversion to petroleum. Honna Formation Conglomerate, sandstone, and shale facies of the Honna Formation on northwest Graham Island contain mature Type III organic matter and have poor hydrocarbon source potential due to low TOC (< 0.43 %). Low QOM (0.7 mg HC/gm C ), HI (<60 mg HC/gm C ), and PI (0.09) values suggest no oil source potential, but possible gas source potential (Tables 5 and 6). SKONUN FORMATION Siltstone and shale in the Skonun Formation exposed in central Graham Island contain Type II organic matter and have good oil and gas generative potential (TOC = 2.47 %; QOM = 2.64 mg HC/gm CQrg; HI = 210 mg HC/gm CQrg; and PI = 0.2). Petrographic analysis of coal and lignite samples from sue onshore wells penetrating the Skonun Formation indicates that the organic matter is predominantly Type III and composed of vitrinite. Some coals (Type III organic matter) respond differently to Rock-Eval pyrolysis than dispersed Type III organic matter and have HI values which plot between Types II and III organic matter (Peters, 1986). The liquid hydrocarbon generative potential calculated from HI data, therefore, can be overestimated for coals (Peters, 1986). Generally immature (0.27 to 0.48 %R°ran(j) Skonun Formation coals have low to moderate QOM values (0.7 to 2.2 mg HC/gm C ) and hence are fair source rocks. 243 Generally low HI values (64 to 179 mg HC/gm CQrg) for marginally mature to mature strata suggest that generated hydrocarbons would consist predominantly of gas and some oil. Hydrogen rich resinite (HI > 500 mg HC/gm CQrg) was observed petrographically which suggests some horizons with good oil source potential. Coals at west Graham Island (Port Louis well) are mature (1.05 %R°ran(i)' however, low QOM (0.87 mg HC/gm CQrg), HI (79 mg HC/gm CQrg), and PI (0.07) values suggest poor hydrocarbon source potential. Snowdon et al. (in prep.) have correlated bitumens from oil seeps associated with Masset volcanic rocks with Jurassic, Cretaceous, and Tertiary source strata predominantly from Graham Island. Bitumens from Otard and Tian Bay (northwest Graham Island) and from Tar Island (east Moresby Island) contain 18alpha(H)oleanane correlated with Tertiary, Type III organic matter derived from terrestrial higher plant material. Bitumens associated with fractures in Masset volcanics near Lawn Hill on the east coast of Graham Island have also been correlated with Tertiary source strata. Bitumen samples from the King Creek area in central Graham Island appear to be derived from Lower Jurassic source rocks. Bitumens from Cretaceous strata have not yet been systematically studied. Factors Affecting Lateral Variations in Source Rock Quality Source rock quality is controlled primarily by the quality, quantity, and DOM of the organic matter. In the Queen Charlotte Islands, the dominant control on the lateral variation in source rock quality for Triassic and Jurassic strata is the DOM of the organic matter, whereas depositional environments are the primary control for Cretaceous and Tertiary strata. Upper Triassic and Lower Jurassic source strata may have been deposited in Hecate Strait and Dixon Entrance but have not yet been confirmed. Even if the strata were deposited, increased burial depths have probably resulted in the levels of organic maturation exceeding the oil window. Any hydrocarbons that were generated may have migrated into less mature strata and preserved. High levels of organic maturation due to high heat flow associated with the San Christoval (SCPS), Burnaby Island (BIPS), and Carpenter Bay (CBPS) Plutonic Suites have resulted in hydrocarbon depletion of the organic matter for the grey limestone member of the Kunga Group. Figure 69 illustrates increasing TOC from west to east on south Moresby Island suggesting that the SCPS was the dominant thermal event. Figure 85 shows very low QOM values with no apparent trend. TOC values for the black limestone member of the Kunga Group increase from east to west (Figure 68) suggesting that pluton emplacement of the BIPS and CBPS were the dominant thermal events on south Moresby Island. TOC values measured on the east side of the BIPS increases from west to east on central Moresby Island suggesting that the pluton emplacement of the BIPS was also the dominant thermal event on central Moresby Island. TOC and QOM (Figure 84) values on northwest Moresby Island increase to the southeast suggesting an offshore source of high heat flow possibly associated with the Langara Island pluton. The Sandilands Formation on Moresby Island is overmature and has low TOC (Figure 67) and QOM (Figure 83) values with no apparent lateral trend (due to sparse data distribution). High TOC and QOM values in central Graham Island suggest that the strata are very good source rocks. The strata near Rennell Sound are overmature and have significantly reduced TOC and QOM values as a result of high heat flow associated with plutonic activity south of Rennell Sound. The Ghost Creek Formation has high TOC (Figure 66) and QOM (Figure 82) values indicating very good source potential. High heat flow associated with plutonism near Rennell Sound has increased the level of organic maturation and decreased the hydrocarbon generative potential of the strata near Rennell Sound as suggested by increasing QOM values from north to south and increasing TOC values from south to north. The Ghost Creek Formation is not exposed south of Cumshewa Inlet and north of Rennell Sound on central Graham Island. Sandilands and Longarm Formations strata are stratigraphically below and 245 above the Ghost Creek Formation (respectively) are exposed on south Moresby Island and northwest Graham Island suggesting that deposition of the Ghost Creek Formation (and possibly the entire Maude Group) was restricted to central Graham Island and north Moresby Island. If such is the case, the limited areal extent of Ghost Creek Formation source rocks suggests a limited potential for hydrocarbon generation and accumulation. TOC (Figure 62) and QOM (Figure 78) values for the Whiteaves Formation tend to increase from southwest to northeast in response to high heat flow from plutonism near Rennell Sound. There is insufficient TOC and QOM data to determine trends for the Fannin (Figures 63 and 79), and Phantom Creek (Figures 61 and 77) Formations. Higher TOC (Figure 59) and QOM (Figure 75) values were obtained from Skidegate Inlet and central Graham Island respectively for the Yakoun and Moresby Groups; however, the paucity of data precludes determination of TOC and QOM trends. TOC values for the Longarm Formation on Moresby Island (Figure 58) increase from east to west. However, there is no apparent trend in QOM (Figure 74). The paucity of data, however, precludes accurate interpretation. The Haida Formation increases in TOC from east to west (Figure 57) suggesting decreased amounts of transported terrestrial organic matter basinward from the western edge of Haida deposition. QOM values from northwest Graham Island (Figure 73) increase towards the south away from plutonism on Langara Island. TOC values are generally lower and HI values are generally higher for the Skidegate Formation relative to the Haida Formation (Figure 56). TOC and HI values increase from west to east for the Skidegate Formation suggesting that there was decreased input of terrestrial organic matter and possibly increased input of marine organic matter in a basinward direction. Higher HI values (Figures 46C and 47C) are observed for the Skidegate Formation than in the Haida Formation (Figures 46D and 47D) suggesting 246 an increased marine component in Skidegate Formation organic matter. QOM values (Figure 72) increase with increasing distance from plutons on Langara Island and Rennell Sound. TOC (Figure 55) and QOM (Figure 71) values are low for the Honna Formation and the paucity of data precludes the determination of TOC or QOM trends. Similarly, lateral trends in TOC (Figure 54) and QOM (Figure 70) for the Skonun Formation cannot be ascertained due to the paucity of data. SUMMARY AND CONCLUSIONS 1. For the most part, Cretaceous and Tertiary strata in the Queen Charlotte Islands contain gas prone Type III organic matter with varying degrees of hydrocarbon source potential. The source rock quality is related primarily to the depositional patterns and the level of organic maturity. Triassic and Jurassic strata (where mature) generally contain a mixture of Type II and Type III organic matter with varying degrees of hydrocarbon source potential related to the level of organic maturation. The Kunga Group and Ghost Creek Formation on central and northwest Moresby Island contain abundant oil and gas prone Type II and significant amounts of oil prone Type I organic matter and have very good petroleum generative potential. 2. Triassic strata from Moresby Island presently have poor oil source potential (QOM < 0.08 mg HC/gm Corg; HI< 16 mg HC/gm Corg; PI < 0.08) due to high levels of organic maturation (2.35 to 8.31 %Roran(j) but may have sourced substantial hydrocarbons in the past. High PI (<0.59) values for overmature strata at Kunga Island suggest hydrocarbon migration into overmature strata. Moderate amounts of residual TOC (< 2.56 %) suggest some gas generative potential remains. The level of organic maturity increases, and TOC decreases from west to east proximal to the BIPS as a result of high heat flow during pluton emplacement. Mature to overmature Triassic strata from central and northwest Graham Island have very good oil and gas source potential as indicated by high TOC (2.17 to 9.6 %), QOM (<4.26 mg HC/gm Corg), and HI (<385 mg HC/gm C ) values. Moderate PI values (0.14 to 0.42) and free hydrocarbons suggest partial 247 conversion of kerogen to petroleum. The hydrocarbon source potential diminishes from east to west with decreasing distance to plutons near Rennell Sound. 3. Jurassic strata from Graham Island and north Moresby Island generally have poor to fair gas generative potential and poor oil source potential. The marginally mature (0.55 %R°ran(i) Ghost Creek Formation is a notable exception and has very good oil and gas source potential as evident by moderate TOC (< 1.73 %), high QOM (<3.73 mg HC/gm Corg), moderately high HI values (<349 mg HC/gm Corg). Low PI (0.07) values, however, suggest minimal kerogen conversion to petroleum. 4. Cretaceous strata of the Longarm, Haida, and Honna Formations on Moresby Island have poor hydrocarbon source potential due to high levels of organic maturity (<4.04 %R°ranci)- Depositional patterns are an important factor controlling the source potential for Cretaceous strata. The Haida Formation on Graham Island contain Type III dispersed organic matter (<2.49 % TOC; HI<79 mg HC/gm CQrg) and has poor to fair gas source potential but no oil generative potential. The Skidegate Formation contains a greater component of marine Type II organic matter than the Haida Formation and has poor to fair gas potential. The Honna Formation on Graham Island has poor hydrocarbon source potential due to lowTOC(<0.43%). 5. Type II organic matter from siltstone and shale horizons in Skonun Formation strata have good oil and gas generative potential (TOC = 2.47 %; QOM = 2.64 mg HC/gm Corg; HI = 210 mg HC/gm Corg; and PI = 0.2). Coals from the Skonun Formation generally have poor hydrocarbon source potential due to low levels of organic maturity (0.27 to 0.48 %R°ran(j)- L°w to moderate HI (64 to 179 mg HC/gm Corg) values for marginally mature to mature coals suggest some gas source potential and oil generative potential. Mature coals at the Port Louis well are poor hydrocarbon sources due to low QOM values (0.87 mg HC/gm Corg). Resinites observed petrographically and associated high HI values (>500 mg HC/gm Corg) suggest some coal horizons have fair to good oil and gas source potential. 248 REFERENCES Bustin, R.M. and Gunther, P.R. 1977 Implications of coalification levels, Eureka Sound Formation, northeastern Arctic Canada; Canadian Journal of Earth Sciences, vol. 14, pp. 1588-1597. Bustin, B.E.B. and Macauiey, G., 1988 Organic petrology and Rock-Eval pyrolysis of the Jurassic Sandilands and Ghost Creek Formations, Queen Charlotte Islands; Bulletin of the Canadian Society of Petroleum Geologists (in press). Cameron, B.E.B. and Tipper, H.W. 1985 Jurassic stratigraphy of the Queen Charlotte Islands, British Columbia; Geological Survey of Canada, Bulletin, v. 365, 49 p. Cameron, B.E.B. 1987 Significance of lower Jurassic hydrocarbon source rocks in the Cumshewa Inlet area, Queen Charlotte Islands, British Columbia; in Current Research, Part A, Geological Survey of Canada, Paper 87-IA, p. 925-928. Conford, C. 1984 Source rocks and hydrocarbons of the North Sea; in Introduction to the Petroleum Geology of the North Sea. ed. K.W. Glennie, London, 1984, 236 pp. Espitalie, R., Madec, M. and Tissot, B. 1977 Source rock characterization method for petroleum exploration; 9th Annual Offshore Technology Conference, Houston, Texas, p. 439-444. Espitalie, R., Deroo, G. and Marquis, F. 1985 Rock-Eval pyrolysis and its applications; Institut Francais du Petrole, reprint No. 27299,132 p. Peters, K.E. 1986 Guidelines for evaluating petroleum source rocks using programmed pyrolysis; American Association of Petroleum Geologists, 70, p. 318-329. Tissot, B.P. and Welte, D.H. 1984 Petroleum Occurrence and Formation; Springer-Verlag, Berlin, 699 p. 249 PART III APPENDICES 250 APPENDIX A 251 Location map for Triassic outcrop sections 252 Location map for Triassic spot samples 253 LOCATION MAP FOR JURASSIC OUTCROP SECTIONS 54°-1-»87-DV-12 2-»Central Graham 3-»Central Graham 4-»Central Graham 5- »BC-Sect.-12 6- »BC-Sect.-15 7^Central Graham 8- »BC-Sect.-1l 9- »Central Graham 10- »Central Graham 11- »BC-Sect.-14 12- »Shields Bay 13- *Rennell Sound 14- »BC-Sect.-10 15- ^Central Graham 16- *Central Graham 17- »BC-Sect.-17 18- »BC-Sect.-9 19- »BC-Sect.-4 20^BC-Sect.-6 21- »BC-Sect.-5 22- *BC-Sect.-8 23-»Maude Island Is., Well-l-278 Is., D Quarry Is., Well-l-179 ls.,-B Quarry Is. Is. A Quarry Branch Rd. ls.,Well-l-178 ls.,-Main Rd. 24- »BC-Sect.-16 25- »BC-»Sect.-7 26- *Whiteaves Bay 27^North Moresby 28- »BC-Sect.-CAA-86-2 29- »87-DV-11 30- »87-DV-5 53°-52°-Location map for Jurassic outcrop sections 25 4 132° LOCATION MAP FOR CRETACEOUS OUTCROP SECTIONS Location map for Cretaceous outcrop sections Location map for Cretaceous spot samples (Graham Island) 25 6 LOCATION MAP FOR CRETACEOUS SPOT SAMPLES (MORESBY ISLAND) 131° B.C. SPOT SAMPLE LOCATIONS 18- +29 19- *28 20- *27 21- ^26 22- »25 23- ^24 24- *23 25- *22 26- »21 27- *20 28- M9 29- M8 30- M7 31- M6 32- M5 33- M4 34- M3 35- M2 36- M1 37- * 4,5,6,7 38- H,2,3 39- »8,9 40- MO 1« 219d25 26 2,8 30 31 1? 192oi 2iJ^L*>*<r 7 38 ( 39 \ 36 \ Y^40 V . 46v45^.^jj 2^——-DV SPOT SAMPLE LOCATIONS 41- *96,97 42- *98 43- »95,99 44-»100 45- M01 46- »93 47- *94 48- *92 49- *91 50- »90 51-»89 52- »88 53- *87 54- *85,86 55- *83,84 56-»81,82 57- *77 58- »70-76 59- »64,65 60- »66 61- »69 62- *67,68 52 — 53^>V crO 5455/56^7 Hi r-52° 10 _1_ 20 _L_ 30 km 132° Location map for Cretaceous spot samples (Moresby Island) 257 132° -54° LOCATION MAP FOR TERTIARY WELLS AND OUTCROP SAMPLES IS 0 L -53° GRAHAM ISLAND /I 54°-10 i 20 30km _l I -»TOW HILL WELL -»NADU RIVER WELL 3- *PORT LOUIS WELL 4- »CAPE BALL WELL 5- *GOLD CREEK WELL 6- >LOG CREEK 7- » TLELL WELL 8- tMILLER CREEK Location map for Tertiary Well and outcrop sections 258 APPENDIX B 259 TMAX vs VITRINITE REFLECTANCE SKONUN FORMATION VITRINITE REFLECTANCE (%Rorand) B TMAX vs VITRINITE REFLECTANCE HONNA FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (%Rorond) TMAX vs VITRINITE REFLECTANCE SKIDEGATE FORMATION 0.5 1 1.5 2 2.5 3 3.5 VITRINITE REFLECTANCE (ZRorand) TMAX vs VITRINITE REFLECTANCE HAIDA FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (%Rorand) Figure showing the variation of T"max ( C) with vitrinite reflectance (^,Rorand): a) Skonun Formation; b) Honna Formation; c) Skidegate Formation; d) Haida Formation 260 TMAX vs VITRINITE REFLECTANCE ALLIFORD FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (%Rorand) TMAX vs VITRINITE REFLECTANCE ROBBER POINT FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (%Rorand) TMAX vs VITRINITE REFLECTANCE RICHARDSON BAY FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (%Rorand) H TMAX vs VITRINITE REFLECTANCE GRAHAM ISLAND FORMATION 0.5 1 VITRINITE REFLECTANCE (%Rorand) Figure showing the variation of Tmax ( C) with vitrinite reflectance (%Rorand): e) Alliford Formation; f) Robber Point Formation; g) Richardson Bay Formation; h) Graham Island 261 TMAX vs VITRINITE REFLECTANCE PHANTOM CREEK FORMATION VITRINITE REFLECTANCE (%Rorand) TMAX vs VITRINITE REFLECTANCE WHITEAVES FORMATION VITRINITE REFLECTANCE (ZRorand) K TMAX vs VITRINITE REFLECTANCE RENNELL JUNCTION FORMATION 600 500 -CJ • in UJ oc •*. Q • X " 1— 400 -300 i 0 0.5 1 1.5 2 VITRINITE REFLECTANCE (%Rorand) TMAX vs VITRINITE REFLECTANCE GHOST CREEK FORMATION 0.5 1 1.5 VITRINITE REFLECTANCE (ZRorand) Figure showing the variation of Tmax ( C) with vitrinite reflectance (%Rorand): ') Phantom Creek Formation; j) Whiteaves Formation; k) Rennell Junction Formation; I) Ghost Creek Formation 262 M TMAX vs VITRINITE REFLECTANCE SANDILANDS FORMATION (KUNGA GROUP) VITRINITE REFLECTANCE (ZRorond) N TMAX vs VITRINITE REFLECTANCE BLACK LIMESTONE MEMBER (KUNGA GROUP) 0.5 1 1.5 VITRINITE REFLECTANCE (ZRorand) Figure showing the variation of T (°C) with vitrinite reflectance (%Ro .): m) Sandilands Formation; n) black limestone ° maxv ' v rand' ' ' member (Kunga Group) 

Cite

Citation Scheme:

    

Usage Statistics

Country Views Downloads
United States 8 0
Canada 4 0
China 2 15
City Views Downloads
Ashburn 8 0
Shenzhen 2 6
Unknown 2 0
Ottawa 2 0

{[{ mDataHeader[type] }]} {[{ month[type] }]} {[{ tData[type] }]}
Download Stats

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0052418/manifest

Comment

Related Items