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UBC Theses and Dissertations

Geology of the Ajax-Monte Carlo property Armstrong, William Paul 1973

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G E O L O G Y O F T H E A J A X - M O N T E C A R L O P R O P E R T Y by WILLIAM PAUL ARMSTRONG B.A.Sc, Un i v e r s i t y of B r i t i s h Columbia, 1965 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n the Department of Geological Sciences We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA June, 1973 In present ing t h i s thes is in p a r t i a l f u l f i l m e n t o f the requirements for an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L ib ra ry s h a l l make i t f r e e l y a v a i l a b l e for reference and study. I fu r ther agree that permission for extensive copying o f t h i s t h e s i s for s c h o l a r l y purposes may be granted by the Head of my Department or by h is representa t i ves . It i s understood that copying or p u b l i c a t i o n o f th is t h e s i s f o r f i n a n c i a l gain sha l l not be allowed without my wr i t ten permiss ion . Department of GEOLOGICAL SCIENCES The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada Date J u n e 1 5 > 1 9 7 3 ABSTRACT The Ajax-Monte Carlo property i s a small porphyry copper deposit located approximately s i x miles south of Kamioops, B r i t i s h Columbia on the south flank of the Iron Mask Ba t h o l i t h . The B a t h o l i t h and successor i n t r u s i v e s were emplaced i n a northwest-trending s t r u c t u r a l element named the Carabine Creek Lineament. Early phases of the b a t h o l i t h were basic and coarse-grained and form the core of the complex. Later phases, of intermediate to a c i d i c composition, were emplaced along the s t r u c t u r a l l y weak margins of the core. Three stages of f r a c t u r i n g were recognized at the property. The e a r l i e s t b recciated the coarse-grained phases p r i o r to the emplacement of the fine-grained i n t r u s i o n s . The second stage of f r a c t u r i n g was synchronous with the a l t e r a t i o n ; the f i n a l stage created the stockwork i n which the m i n e r a l i z a t i o n was concentrated. The p r o p y l i t i c a l t e r a t i o n f a c i e s developed at the property i s t y p i c a l of porphyry copper deposits except that only minor q u a n t i t i e s of quartz are present. The potassic f a c i e s i s d i s t i n c t l y d i f f e r e n t i n that i t lacks abundant red orthoclase and b i o t i t e . P y r i t e and chalcopyrite are the most abundant s u l f i d e s ; and bornite i s o c c a s i o n a l l y observed. Magnetite i s a common accessory i n the basic i n t r u s i v e s . - i -TABLE OF CONTENTS CHAPTER I INTRODUCTION Page LOCATION 1 SCOPE 1 PHYSIOGRAPHY 2 PREVIOUS GEOLOGICAL WORK 2 HISTORY AND DEVELOPMENT 3 ACKNOWLEDGMENTS 4 CHAPTER II GENERAL GEOLOGY REGIONAL GEOLOGY 5 REGIONAL STRUCTURE 8 CHAPTER III LOCAL GEOLOGY GENERAL INTRUSIVE HISTORY 11 PETROLOGY 12 NICOLA GROUP 12 INTRUSIVE ROCKS OF THE IRON MASK BATHOLITH 13 Pre-Mineralization Assemblage (Coarse Grained 13 Suite) Iron Mask Gabbro 13 Iron Mask Diorite 14 Intra-Mineral Assemblage 16 Microdiorite 16 Lobe Porphyries 18 - i i -Page Lobe Diorite 19 Lobe Monzonite 21 Micromonzonite 23 Jacko Porphyry 26 Post Mineralization Intrusives 28 Peridotite 28 Rhyolite 30 EXTRUSIVE ROCKS 32 Kamloops Group 32 Olivine Basalt 32 ALTERATION 35 PROPYLITIC ALTERATION 36 Eastern Zone 36 Ajax Zone 39 Discussion 40 POTASSIC ALTERATION 42 Ajax Zone 43 Wheal Tamar Zone 43 Discussion 44 STRUCTURE 47 Phase I Fracturing - The Ajax Breccia 48 Phase II Fracturing - Synchronous with Alteration 49 Phase III Fracturing - The Sulphide Bearing Stockwork 49 MINERALIZATION 59 PRIMARY MINERALS 60 Magnetite 60 Pyrite 60 i i i -Page Chalcopyrite 61 Bornite 61 Gold SECONDARY MINERALS 62 CONCLUSIONS 63 BIBLIOGRAPHY 65 - iv -ILLUSTRATIONS Figure 1. Regional Geology, after Cockfield and Preto Scale 1" to 4 miles Page 6 2. Intrusive Bodies along the Carabine Creek Lineament 9 Scale 1" to 6 miles 3. Compatibility diagram for propylite alteration 38 with high CO2 pressure, s i l i c a and water in excess. From Creasey (1966) 4. Univariant equilibrium curves for epidote and 41 Al-serpentine. From Creasey (1966) 5. Some st a b i l i t y relationships in the system 45 K20 - A1 20 3 - Si0 2 - H20 at 15,000 psi total pressure. From Hemley (1959) 6. Experimental dehydration curves for the sta b i l i t y 46 limits of kaolinite, Al-montmorillonite, and pyrophyllite. From Creasey (1966) 7. Poles to Phase III Fractures. Lower hemisphere 51 projection 8. South Adit, Ajax Zone 53 Scale 1 inch to 10 feet 9. North Adit, Ajax Zone Scale 1 incb to 10 feet 10. Pit over South Adit, Ajax Zone Scale 1 inch to 10 feet 11. Wheal Tamar Shaft Scale 1 inch to 10 feet 12. : Monte Carlo Shear Zone Scale 1 inch to 10 feet 13. Geology - Ajax-Monte Carlo Property Scale 1 inch to 300' 14. Alteration, Ajax-Monte Carlo property Scale 1 inch to 300* 15. Sections A A' and B B' Scale 1 inch to 300' 54 55 56 58 in pocket in pocket in pocket - V -Plate Page I Iron Mask Gabbro (X-6) 68 II Ajax Breccia (X%) 68 III Microdiorite (X6) 69 IV Peridotite (XI) 69 V Peridotite (X15) 70 VI Lobe Diorite (X6) 70 VII Lobe Diorite Porphyry (X6) 71 VIII Lobe Diorite Porphyry (X6) 71 IX Lobe Monzonite (X6) 72 X Micromonzonite (X6) 72 XI Rhyolite (X6) 73 XII Potassic Alteration Wheal Tamar Zone (X6) 73 XIII Ajax Breccia 74 XIV Ajax Breccia (XI) 74 XV Wheal Tamar Zone 75 XVI Ajax North Adit 75 - 1 -GEOLOGY OF THE AJAX-MONTE CARLO PROPERTY, KAMLOOPS MINING DIVISION BRITISH COLUMBIA CHAPTER I INTRODUCTION This thesis describes the Ajax-Monte Carlo Property, a small porphyry copper deposit on the southwest flank of the Iron Mask Bat h o l i t h i n i t s geological and s t r u c t u r a l s e t t i n g . LOCATION The Ajax-Monte Carlo Property i s located i n the Kamloops Mining D i v i s i o n at Latitude 50° 30' N., Longitude 120° 22' W. The nearest centre i s Kamloops, B.C., about 6 miles to the northwest. Access to the property i s by good gravel roads v i a the small community of Knutsford. SCOPE The data f o r t h i s study were gathered during the 1967 f i e l d session i n conjunction with exploration work on the property. Because less than 5 percent of the surface i s outcrop, most information was obtained by study of diamond d r i l l core. S p a t i a l r e l a t i o n s h i p s and - 2 -distribution of lithologic units are inferred from d r i l l hole Intersections and therefore are subject to interpretation. This thesis encompasses a study of the mineralisation in relation to the paragenesis of igneous intrusion and the effects of regional and local structures. PHYSIOGRAPHY Much of the area occupied by the batholith is open grassland, with timber only on the higher slopes. Relief is moderate, and glacial action has created a topography of low, ro l l i n g h i l l s . Light r a i n f a l l is reflected in the flora of the area. Sagebrush and cacti are abundant on the lower grassy slopes. Water is abundant in the spring in numerous small saline ponds and sloughs. In summer and f a l l , however, Jacko Lake is the only large body of water in the claim area. PREVIOUS GEOLOGICAL WORK General reconnaissance geology of the Iron Mask Batholith was f i r s t recorded by G.M. Dawson in 1877 and 1894 with additional work by R.A. Daly in 1911-12. Mathews (1941) studied the petrology of the major phases comprising the batholith and noted the peripheral distribution of copper deposits. Cockfield (1949) made the f i r s t systematic study of the numerous copper showings associated with the batholith and described them briefly in the Geological Survey of Canada Memoir 249. Continued exploration interest in the area resulted in two studies of the - 3 -b a t h o l i t h and associated deposits by the B.C. Department of Mines. Carr (1956) separated the phases of the b a t h o l i t h into two categories based on te x t u r a l and f i e l d r e l a t i o n s h i p s . These categories, each containing several v a r i e t i e s of i n t r u s i v e rocks, were termed the coarse-grained s u i t e and the fine-grained s u i t e . Carr made an important contribution i n suggesting a paragenetic sequence for the i n t r u s i v e s co mprising the ba t h o l i t h , and i n r e l a t i n g the i n t r u s i v e body to regional zones of s t r u c t u r a l weakness. In the second study of the b a t h o l i t h , Preto (1967) described several p o r p h y r i t i c younger v a r i e t i e s of the i n t r u s i v e complex and recognized t h e i r close a s s o c i a t i o n with m i n e r a l i s a t i o n . HISTORY AND DEVELOPMENT The o r i g i n a l Ajax, Monte Carlo, Neptune and Sultan Crown-granted mineral claims were located i n the ea r l y 1900's. During the next two decades, the owners sank numerous p i t s and shallow shafts on outcrops which were stained with copper carbonates or contained copper sulphides. Cominco Lt d . optioned the claim group i n 1928 and did approximately 5000 f t . of diamond d r i l l i n g and minor underground development i n the Monte Carlo a d i t . Berens River Mines Ltd. (Newmont) optioned the property i n 1952 and d r i l l e d on a narrow high-grade shear zone on the Monte Carlo claim near the old a d i t . In 1954, Cominco again optioned the four o r i g i n a l Crown grants together with adjacent - 4 -crown-granted claims, staked additional claims and proceeded to carry out intermittent exploration programs up to the present time. ACKNOWLEDGMENTS The writer would like to acknowledge the guidance of J. Richardson and Dr. J.M. Allen of Cominco Ltd. while exploration work was being performed on the property. Discussions with Dr. V.A.G. Preto of the B.C. Department of Mines were invaluable in sorting out the numerous varieties of intrusive types, as well as the structure of the area. Thanks also are due to Cominco Ltd. for permission to publish this thesis and for bearing the cost of map reproduction, and certain of the photographs. The experience and knowledge of the area which the late Dr. J.A. Gower possessed were an invaluable resource to the author. - 5 -CHAPTER II GENERAL GEOLOGY REGIONAL GEOLOGY The Iron Mask Batholith lies in the southeast corner of a large structural element known as the Quesnel Trough (Roddick et. a l . , 1967) and (Campbell and Tipper, 1970). Formation of the trough probably commenced at the close of the Paleozoic and an extensive system of structural weakness and faulting developed in the interior at this time (Douglas et. a l . , 1970). It seems probable that the ancestral fault system into which the Iron Mask Batholith and successor intrusives were emplaced was generated at this time. Subsidence of the trough began in the area in Upper Triassic time with the deposition of the Nicola Formation. Deformation, intrusion and u p l i f t associated with the Inklinian orogeny (Douglas et. a l . , 1970) followed rapidly, commencing in the latest Triassic with the emplacement of a number of batholiths, including the Guichon Creek Batholith and i t is postulated that intrusive activity in the Carabine Creek Lineament-may have begun at this time as well with the emplacement of the earlier phases of the Iron iMask Batholith. Erosion during the Lower Jurassic unroofed the Guichon Creek Batholith. However, whether or not this stage was reached with the Iron Mask Batholith is unknown. Removal of superincumbent load progressed at least to the point where hypabyssal textures developed in 3I°00' LEGEND TERTIARY MIOCENE OR EARLIER KAMLOOPS GROUP 10 10 T R A N Q U I L L E B E O S c o n g l o m e r a t e , s h o l e , c o a I , t u f f 8 C O L O W A T E R B E O S c o n g l o m e r a t e , s h a l e , c o a l , CRETACEOUS OR TERTIARY C A R A B I N E C R E E K I N T R U S I V E S g r a n i t e , g r a n o d i o r i t a , g r a n i t e p o r p h y r y a n d e t l t e , b o i a i t , p e r i d o t i t e , o g g I o m e r a t e , b r e c c i a c o n g l o m e r a t e , s a n d s t o n e , s h a l e CRETACEOUS LOWER CRETACEOUS K I N G S V A L E O R O U P v o l c a m c s , a r k o s e , c o n g l o m e r a t e TRIASSIC UPPER TRIASSIC AND ( T) LATER I N T R U S I V E S b a t h o l i t h i c c o m p l e x e s 3 a h y p o b y s s a l p h a s e s o f I r o n M a s k b a t h o l i t h UPPER TRIASSIC 2 | N I C 0 L A ' O R A T I O N g r . e n . t o n e . a n d . s i . i c a n d b a s a l t i c v o l c a n i c s , m i n o r s e d i m e n t s PALEOZOIC UNDIVIDED i n c l u d e s C A C H E C R E E K G P a n d u n d i v i d e d s e d i m e n t s a n d m e t a s e d i m a n t s G U I C H O N C R E E K B A T H O L I T H M O O I F I E O A F T E R SCALE C O C K F I E L D A N D P R E T O I " 1 4 MILES - 7 -the succeeding intrusive phases. By Lower Cretaceous time the area to the southwest was emergent intermittently as evidenced by the continental elastics of the Kingsvale Group. In the northwest portion of the Carabine Creek Lineament, greenstones containing fragments believed to be derived from the Iron Mask Batholith are tentavely correlated with the Kingsvale Group by Cockfield (1947). Coarse clastic sediments of Upper Cretaceous (?) age are also localized in the northwestern Carabine Creek Lineament, as well as south of Kamloops Lake. Immediately overlying these conglomerates in the Carabine Creek area is a volcanic assemblage comprising basaltic breccias, tuffs, and augite porphyries with occasional bands and lenses of ultrabasic rock which are termed "picrite porphyry" (Cockfield, 1949). Cockfield's description of the picrite in this area very closely resembles the peridotite found on the Ajax-Monte Carlo property, and these occurrences are correlated on this basis by the present author. In addition, the relatively fresh augite porphyry (Jacko porphyry) found in the thesis area north of Jacko Lake is provisionally assigned to this group on the basis of lithologic similarity. Small intrusive bodies of intermediate to acid composition were emplaced in late Cretaceous or early Tertiary time in the Carabine Creek Valley. These cut the coarse elastics and volcanic rocks mentioned above, and mark the cessation of igneous activity in the Carabine Creek Lineament. The final major depositional event in the area was the - 8 -extrusion of the Kamloops basalt over a substantial portion of the central interior, and the associated deposition of the Tranquille Beds and the Coldwater Beds in isolated continental basins. REGIONAL STRUCTURE The Carabine Creek Lineament, the dominant structure in the area, is a northwest-trending structural discontinuity about 30 miles long which extends from Shumway Lake in the southeast across Kamloops Lake and up the valley of Carabine Creek in the northwest (Figure 1). Evolution of the ancestral Carabine Creek Lineament may have begun as early as the close of the Paleozoic during the Cassiar orogeny when large northwest-trending breaks such as the Pinchi Fault system were generated, though intrusive activity along the lineament probably did not commence until late Triassic or early Jurassic time. Intermittent tectonic activity along the lineament allowed intrusion of successively younger phases of the batholith culminating in the Tertiary with the intrusion of the small stocks in the Carabine Creek Valley. Carr (1956) believed that three zones of recurring fracture played an important part in localizing the batholith and were the loci of intrusive activity during the evolution of the batholith. Preto (1967) noted that the occurrence of the younger hypabyssal intrusive phases is restricted to Carr's fracture zones. - 9 -I2I°00' ;5i°ool 5% 0^ A J AX - MONTE CARLO PROPERTY LEGEND P L U T O N I C R O C K S Iron Mask G a b b r o , Diorite Ml crod ior it e SOUTH 'A KAM LOOPS HYPABYS S A L ROCKS L o b e Porphyr ies Cherry Creek Intrusivas 3 PERI DOTITE SCALE 1 = 6 M I L E S FIGURE 2 INTRUSIVE BODIES ALONG THE CARABINE CREEK LINEAMENT - 10 -Evidence suggesting the Nicola rocks were folded prior to emplacement of the early intrusive phases of the Iron Mask Batholith is described by Mathews (1941) and Jones (1957). Mathews, in describing the Nicola Group near the southeast-end of the batholith, states that the batholith has intruded the northeast limb of a syncline whose axis occurs near Edith Lake and trends northwesterly. Jones states that the Nicola rocks at the northwest corner of the batholith near Hughes Lake strike northwesterly parallel to the long axis of the batholith. Near the contact, dips are steep southwesterly but become flatter to the south-west, away from the batholith. From this, he infers a synclinal axis to the southwest of the batholith, which agrees with Mathew's conclusion that the batholith was emplaced discordantly into the northeast limb of a syncline. - 11 -CHAPTER III LOCAL GEOLOGY GENERAL INTRUSIVE HISTORY The Ajax-Monte Carlo deposit occurs on the southwestern margin of the Iron Mask Batholith adjacent to the contact with the Nicola Group, but is entirely contained within the intrusive rocks of the batholith. Intrusive activity is thought to have commenced during Upper Triassic or Lower Jurassic time during the Inklinian Orogeny. The f i r s t phases to be emplaced in the Carabine Creek Lineament were the gabbro, pyroxenite and diorite comprising the coarse crystalline suite of the Iron Mask Batholith. These early basic and coarsely crystalline varieties form the core of the batholithic complex. Continuing stress release along the lineament allowed the intrusion of successive phases along the structurally weak upper margins and crest of the rigid crystalline core. Emplacement of the younger hypabyssal varieties distributed along the upper margin and periphery of the plutonic core suggest f i r s t l y that the core rocks were crystalline and competent, and that unroofing of the complex has progressed to the stage where more rapid c h i l l i n g of the magma took place, generating the porphyritic textures of the Sugarloaf suite and the potash-rich Cherry Creek porphyry. Intrusive activity along the lineament appears to have continued into Cretaceous or Tertiary time with the intrusion of the - 12 -Carabine Creek Stocks on the North side of Kamloops Lake. Late dikes and intrusions of probable Tertiary age mark the cessation of intrusive activity in the area. On the Ajax property, intrusive varieties representing most of the stages of evolution of the batholith are present. Due to the limited exposure, however, l i t t l e can be said regarding distribution, abundance and intrusive relationships beyond that information which is obtained from d r i l l cores. PETROLOGY NICOLA GROUP The rocks of the Nicola Group do not outcrop in the thesis area and consequently were not examined during the course of work on the property. Descriptions from the literature (Schau, 1964), Cockfield (1949) indicate the bulk of the Nicola Group is volcanic in origin with associated minor limestone, a r g i l l i t e and conglomerate. Lithologies of the volcanogenic members are diverse including amygdaloidal lavas, porphyries, breccias, agglomerates and tuffs. Material of andesitic composition predominates; basaltic or dacitic rocks are uncommon. Alteration i s apparently widespread, with extensive development of chlorite, calcite and epidote. U r a l i t i c alteration of pyroxenes is also common. - 13 -INTRUSIVE ROCKS OF THE IRON MASK BATHOLITH Pre-Mineralization Assemblage (Coarse-Grained Suite) Iron Mask Gabbro This rock type is the oldest of the Iron Mask intrusive assemblage and, together with the Iron Mask Diorite, comprises the coarse-grained crystalline core of the complex. It is distributed along the northern edge of the Ajax-Monte Carlo property in breccia contact with the younger phases to the south. In hand specimen, the gabbro is typically dark green in colour and is medium to coarse grained. No planar or linear fabric is discernable. The composition is quite variable and ranges from plagioclase-free pyroxenitic varieties to those containing approximately 50 percent plagioclase. Accessory magnetite is typically abundant, and occasionally is concentrated in lenses to 5 feet in length. Augite, which is generally unzoned, occurs as large stubby subhedral crystals. Plagioclase, when present, is generally subhedral producing a texture which is sub-ophitic as can be seen in Plate I. Magnetite is i n t e r s t i t i a l . Deuteric alteration is common, especially in plagioclase-rich varieties, and augite is altered to hornblende along crystal outlines and cleavage planes. Plagioclase is invariably riddled with hydromica which makes composition determinations impossible to obtain. Partial alteration of magnetite to ocherous hematite is also f a i r l y common (Plate I). - 14 -Mode (a) Typical gabbro (extensively altered): Mineral Percentage Hornblende 71.6 Plagioclase 17.0 Pyroxene 1.0 Sericite 8.4 Accessories 1.0 Opaques (magnetite, hematite) 1.0 (b) Typical pyroxenite (unaltered): Hornblende 1.0 Pyroxene 85.0 Opaques (magnetite) 14.0 Iron Mask Diorite This species is less abundant than gabbro and from mutual contacts appears to have crystallized later than the gabbro. It is easily rocognized in the f i e l d being medium to coarse grained with long blades of hornblende to 2.5 cm. surrounded by subhedral plagioclase to 1.5 cm (Plate II). Linear or planar fabrics are generally absent except near contacts with the older gabbro where hornblende crystals occasionally are sub-aligned in trachytoid textures. Grain size is quite variable and commonly changes rapidly over distances as small as a few inches, which gives rise to the schleiric texture - 15 -described by Mathews (1941). Contacts with the gabbro are generally sharp and exhibit l i t t l e evidence of assimilation. Under the microscope, hornblende occurs in long narrow blades. Colour is grey-green, and weakly pleochroic. Plagioclase occurs in anhedral crystals which are generally smaller than the hornblende. Albite twinning is common, and crystals are unzoned. Rounded quartz grains with undulatory extinction are present in trace amounts. Alteration of the diorite is ubiquitous. Hornblende is extensively altered to chlorite along cleavages and crystal boundaries so that often only a few fragments of hornblende remain. Development of biotite after hornblende has been observed although this is relatively uncommon. In the thin sections studied, plagioclase is seldom fresh, but shows extensive alteration to hydromica along twin planes and crystal boundaries. Crystals suitable to compositional determinations are very rare and the composition obtained, Anyrj, is based on one determination. Although several thin sections were studied, only one was suitable for determination of anorthite content (An^). - 16 -Mode Mineral Percentage Hornblende 51.8 Plagioclase 39.0 Biotite 2.3 Quartz 1.0 Opaques 5.8 Intra-Mineral Assemblage Microdiorite Fresh, medium grey microdiorite is fine to medium grained, allotrimorphic-granular. On the property, extensive propylitization has given i t a buff to greenish white colour. The plutonic texture, even grain size and lack of foliation or lineation are characteristic of this species. restricted to the western area or Ajax Zone where i t forms the host for most of the mineralization. The combination of lack of outcrop and intense alteration make i t d i f f i c u l t to determine age relations with other intrusive varieties. However, i t does postdate the Iron Mask Gabbro and Diorite because their mutual contact on the north edge of the property is a breccia zone, with fragments of the coarse-grained suite in a matrix of microdiorite. Other contact relationships are less conclusive and are discussed later. The bulk of the microdiorite on the property is - 17 -Mode Mineral Percentage Hornblende 39.5 Plagioclase 47.4 Biotite 4.0 Epidote 7.6 Opaques (sulphides) 1.4 Quartz 1.0 Augite 1.0 Hornblende occurs as stubby, ragged crystals which display a medium green to yellow-green pleochroism. Generally the hornblende is extensively replaced by chlorite and less commonly, by biotite. Augite is uncommon and exists as fragmentary remains only. Alteration of this mineral is not extensive and i t s destruction appears to have taken place as much by comminution as by chemical attack. The plagioclase exists in small, unzoned anhedral grains with only a few displaying crystal outlines. It is invariably altered, either dusted with fine opaque material, or riddled with hydromica or epidote; and forms the bulk of the rock. The fabric is typically plutonic with a mosaic of interlocking grains of mafic minerals, plagioclase and trace amounts of quartz (Plate III). - 18 -Lobe Porphyries This i s an assemblage of microporphyritic rocks of intermediate to acid composition which on the east side of the property form a lobe-like salient from which the name is derived. The distribution of this group is restricted to the northwest corner and flanks of the batholith, and as noted by Preto, appear to have been emplaced along the fracture zones described by Carr. Although comprising a number of intrusive species of slightly different compositions and varying textures, they have been grouped as the Sugarloaf Intrusives by Preto because of their obvious spatial and genetic a f f i n i t i e s . Sugarloaf diorite from the type locality on Sugarloaf H i l l commonly contains stubby equant phenocrysts of hornblende in a fine-grained feldspathic matrix whereas the equivalent rock types in the thesis area contain long, bladed crystals of hornblende, and often euhedral grains of plagioclase. Because of the textural differences, i t is thought that the Sugarloaf varieties present in the thesis area warrant the distinction of a separate name, the "Lobe Porphyries". The two most important varieties are the Lobe diorite and the Lobe monzonite, each of which has numerous textural variants. Character-i s t i c of this suite is the distinct hypabyssal texture which distinguishes i t from the coarse crystalline suite, and from microdiorite. Also included in this group is an assemblage of microporphyritic rocks which Preto has mapped separately as the Cherry Creek intrusives. These are similar texturally to the Sugarloaf suite but are characterized by an abundance of brick-red orthoclase. There has been some discussion - 19 -among workers whether this variety is a separate intrusive phase or whether the unusually high concentration of orthoclase in the rock i s the result of potassium s i l i c a t e alteration of Sugarloaf or Lobe Porphyry. Lobe Diorite This species is medium green-grey coloured and is fine to medium grained. Fresh specimens show hornblende crystals to 1-2 mm. in length which are commonly ragged, fragmented and bent. The texture is not distinctly porphyritic but in some cases hornblende crystals reach 2 cm. in length (Plate VI). Preferred orientation is common as seen in Plate VII. The degree of cr y s t a l l i n i t y of the feldspars ranges from a mosaic of subhedral grains to distinctly euhedral crystals forming crowded feldspar porphyries (Plate VIII). The porphyritic nature of the rock is often masked by alteration which affects the plagioclase and leaves ghosts which are apparent only under the microscope. Altered varieties of this rock are thus easily confused in the f i e l d with microdiorite. Moderate alteration is almost always present and the most obvious effects observed in'...'the f i e l d are frequent patches of epidote in the matrix. The effects of alteration are much more apparent under the microscope. Hornblende, in long ragged crystals, commonly shows serrated terminations suggesting reaction with the melt phase. Oscillatory zoning of the larger crystals i s frequently observed. Minor amounts of chlorite are present. Alteration of mafic minerals to tremolite-actinolite is also present in some sections. - 20 -Plagioclase occurs in euhedral to subhedral laths which rarely exceed 5 mm. in length and are invariably highly altered. Trachytoid texture is common, especially in the more porphyritic varieties. Unaltered specimens suitable for optical determination of composition are exceedingly rare. One determination obtained from a specimen from Sugarloaf H i l l gave the composition An^g. In most of the sections studied, plagioclase is altered to a translucent cottony mass of sericite and a clay mineral (montmorillonite?). Highly altered plagioclase crystals Imay display a rim of unaltered feldspar. This material has positive r e l i e f , and therefore probably is an unaltered rim of a previously zoned crystal, rather than a rim of albite resulting from alteration. In the groundmass, orthoclase is not abundant and generally occurs as small euhedral grains i n t e r s t i t i a l to the phenocrysts. Alteration is usually advanced to the stage where orthoclase is not readily identifiable in unstained slides, even though i t is theore-t i c a l l y stable in both alteration facies present. Clinozoisite is common is disseminated granules and in larger p o i k i l i t i c grains which pseudomorph hornblende. Calcite, tremolite, apatite, and chlorite are present in the matrix in small quantities. Quartz, which occurs in very small grains in the matrix, constitutes less than one percent of the rock. - 21 -Mode Mineral Percentage Hornblende 9.5 Actinolite 7.9 Plagioclase (phenocrysts) 31.7 Plagioclase (matrix) 26.7 Orthoclase 13.1 Sericite 1.6 Accessories (quartz, calcite, sphene) 4.3 Opaques (magnetite, pyrite) 5.2 A l l porphyritic rocks of d i o r i t i c composition in the thesis area are grouped together under the name "Lobe Diorite". In hand specimen the most obvious lithologic variation is in the degree of c r y s t a l l i n i t y of the plagioclase (Plate VIII). This distinction is more apparent than real since under the microscope the type Lobe Diorite shows euhedral ghosts of plagioclase. Also apparent from the plates is the difference in habit of the hornblende. It is on this baiss that the Lobe Diorite i s differentiated from the type Sugarloaf diorite. Lobe Monzonite Unaltered Lobe monzonite is a distinctly porphyritic rock containing abundant small phenocrysts of plagioclase in a matrix of orthoclase, quartz and minor hornblende. It is texturally similar - 22 -to the Lobe diorite but is distinguished on the basis of somewhat lighter colour and a faint pinkish-orange hue due to more abundant orthoclase and lesser amounts of mafics. It is not particularily abundant on the property. Known occurences are restricted to the eastern part of the property. Mineralized Lobe monzonite has been observed in core but in general i t is not an important host of ore. Information regarding age relationships with other intrusive types is very limited because contacts are observed only in core. It obviously post-dates the coarse crystalline suite since i t contains fragments of gabbro (Plate IX). In d r i l l core from hole 52, i t appears to have intruded the Lobe diorite and the contacts with i t appear to be chilled. Plagioclase phenocrysts (An^^) show l i t t l e variation in size and are generally .5 cm. or less in length. They are usually euhedral and albite twinning is common. Phenocrysts are more abundant and closely packed than in the diorite porphyries, and trachytoid texture is common. Zoning of the phenocrysts is present, though frequently masked by alteration, and compositional variations across the crystals are unobtainable. Euhedral crystals of hornblende generally are altered to tremolite-actinolite. I n t e r s t i t i a l to the euhedral phenocrysts of plagioclase is a fine-grained mosaic of anhedral quartz and orthoclase. Quartz grains range from about .25 mm. to 1 mm. and have rounded boundaries, - 23 -whereas orthoclase i s sub-poikilitic in grains to 1mm. Alteration of the cores of the orthoclase grains to a clay mineral (montmorillonite?) is frequent. The matrix contains small amounts of granular clinozoisite, apatite, sphene, calcite, and euhedral pyrite. Mode Mineral Percentage Plagioclase 29.7 Orthoclase 22.9 Quartz 14.0 Tremolite - actinolite 7.3 Chlorite 13.4 Accessories (epidote, calcite) 9.9 Opaques (magnetite, sulphides) 2.8 Aside from small changes in^the amount of phenocrysts, l i t t l e variation in composition or texture has been observed. Micromonzonite Texturally this rock is similar to the microdiorite, in that i t i s fine-grained hypidiomorphic-granular and lacks the hypabyssal appearance of the Lobe porphyries. In general i t i s leucocratic; however, some varieties contain minor hornblende. Its - 24 -pinkish-grey colour and characteristic texture make i t easy to recognize in the f i e l d . The main body of micromonzonite on the property occurs in the north-central area where i t has intruded microdiorite and rocks of the coarse crystalline suite. Elsewhere on the property, small bodies of micromonzonite have a dike-like aspect, and contain fragments of Lobe diorite and Lobe feldspar porphyry. Carr (1956) in describing an occurrence of micromonzonite within a body of serpentinized peridotite in hole 23 inferred that the micromonzonite has intruded the peridotite. Examination of the core by the author did not result in any definitive evidence regarding the relative ages of the rocks in question, From this, i t appears that the micromonzonite was emplaced later than the Lobe porphyries and as such represents a departure from the general trend from older plutonic-textured basic rocks to younger prophyritic acidic phases. Plagioclase, the most abundant mineral species, occurs as a mosaic of stubby laths and crystals. Albite twinning is common, but the crystals are unzoned and are not preferentially oriented. As implied in the name, the size of the crystals is small, averaging about 2.5 mm. in length. Alteration i s moderate with development of hydromica along twin planes and crystal boundaries. The cores of some crystals are clouded with an amorphous aphanitic material which is probably montmorillonite. Optical determinations indicate a composition of An3Q to An35# Orthoclase occurs in anhedral grains which may partly - 25 -enclose plagioclase laths in a sub-poikilitic texture. In plane light, the crystals have a dusty appearance which is perhaps due to inclusion of finely divided hematite. Quartz i s present in small quantities as rounded equant grains to 2 mm. Hornblende is present in small amounts in subhedral unzoned crystals displaying light tan to green pleochroism. No alteration was observed. Clinozoisite, apatite and calcite comprise the accessory minerals. Mode Mineral Percentage Hornblende 26.1 Plagioclase 44.9 Orthoclase 2.5 Sericite 8.9 Epidote 14.4 Quartz 1.6 Opaques (pyrite, chalcopyrite) 1.6 The dike-like distribution, relatively weak alteration and lack of mineralization associated with this rock type suggest that i t was intruded subsequent to the mineralization and alteration on the property, but conclusive evidence is not available. - 2 6 -Jacko Porphyry This intrusive variety outcrops on the western edge of the property and forms the low bluffs to the north of Jacko Lake. Its contact relationships with other intrusive types are sufficiently obscure to reduce an estimation of i t s relative age to a matter of speculation. Near the eastern side of Jacko Lake, however, a small test pit has been excavated to expose a narrow fracture containing pyrite, chalcopyrite and calcite. No other mineralization has been observed in this species, however. It is provisionally included with the intra-mineral intrusive assemblage. As evidenced by the name, the rock i s porphyritic, with small (1 cm.) equant phenocrysts of hornblende in a fine-grained granular matrix. On a weathered surface, the porphyritic nature is particularly apparent, and i t was on this basis that f i e l d identification was made. Preferred orientation of phenocrysts is not present, although scattered throughout the rock are occasional narrow (5 cm.) irregular streaks of fine-grained granular material which is devoid of phenocrysts. The colour of the rock on a fresh surface is a dark greenish-grey due to the predominance of hornblende. Phenocrysts are bimineralic, with cores of augite and rims of secondary hornblende. The nucleii often show oscillatory zoning, and extensive alteration has produced a sieve-texture especially near the rims of the augite crystals. - 27 -Hornblende is the most abundant mineral species and occurs as alteration rims as mentioned above and as mats of stubby crystals, commonly with a preferred orientation. Pleochroism is distinct and colours are yellow to green. The crystals are fresh and unaltered, which is in marked contrast to plagioclase. The presence of plagioclase i s indicated only by lath-shaped ghosts of hydromica. Small amounts of biotite, calcite, and traces of magnetite are also present. Mode Mineral Percentage Hornblende 60.2 Sericite (after plagioclase) 29.1 Pyroxene 5.3 Chlorite 3.2 Quartz 1.3 Accessories & opaques 1.0 It should be noted that other workers have not mapped the Jacko porphyry as a separate intrusive phase and have presumably included i t with rocks of the Coarse crystalline suite since there is a marked resemblance to some of the more pyroxenitic varieties of Iron Mask Gabbro. The limited exposures and lack of diamond d r i l l - 28 -holes in this area make i t d i f f i c u l t to come to a definite conclusion. However, the writer has provisionally classified these rocks as a separate intrusive type because of i t s distinct hypabyssal texture, lack of mineralization, and absence of accessory magnetite. Post-Mineralization Intrusives Peridotite Small lenticular bodies of peridotite have been mapped by Carr along the Carabine Creek lineament, and several occur on the property. Most are strongly sheared and serpentinized, but one outcrop of fresh material occurs about one-quarter mile southeast of the property. The close spatial relationship between the peridotite bodies and the major breaks in and adjacent to the batholith was noted by Carr and Preto, but a genetic relationship has not been proposed. On the property, peridotite is distributed along the southern edge of the property and appears to underly the Lobe diorite on the eastern side of the Monte Carlo zone. In fresh specimens, i t is dark green and dense, commonly with greenish ovoid remnants of olivine crystals to 1 cm. in a dark aphanitic matrix. Some of the serpentinized material displays a glomeroporphyritic texture with clusters of pheno-crysts in a dark grey serpentinized matrix (Plate IV). A specimen of fresh peridotite from the locality one-quarter mile from the property was studied in thin section since unaltered material does not occur on the property. It has large (1 cm.) - 29 -closely-packed ovoid crystals of olivine in varying degrees of ser-pentinization. Typically, the olivines are fractured and veined with serpentine, and are rimmed with selvages of antigorite and magnetite. The phenocrysts show no preferred orientation. Some olivine crystals in advanced stages of serpentinization have antigorite rims with associated coarse euhedral grains of magnetite, whereas the centres of the crystal sites have been reduced to felted mats of chrysotile with disseminated, very fine-grained magnetite. The groundmass consists of a granular aggregate of small (0.1 mm.), euhedral pyroxene crystals, identified by Mathews (1941) as pigeonite, in a glass matrix. This glass is generally fresh and unaltered and only occasionally is i t cloudy and semi-opaque. Spherulitic cracks are uncommon as is strain birefringence. Serpentine was not observed in the matrix. Spinifex textures are absent. Specimens from the property show vestiges of olivine with abundant serpentine and magnetite in phenocryst sites (Plate V). The groundmass is completely altered to a fine-grained mat of serpentine, magnetite and talc (?). Directional textures are occasionally visible, presumably generated by shearing. - 30 -Mode Mineral Percentage Olivine 30.7 Serpentine 27.0 Augite 25.5 Talc 4.7 Opaques (magnetite) 12.1 Rhyolite A branching dike of rhyolite traverses the property in a north-easterly direction. Thickness is less than 40 feet but i t has been traced in d r i l l holes for a strike length in excess of 3000 feet. Rhyolite intrudes mineralized Lobe porphyries, microdiorite and also micromonzonite, but i t is completely barren and unaltered, and so was emplaced after the mineralization and alteration. Chilled margins suggest the intrusive complex had completely cooled prior to the intrusion of the rhyolite. Its fine grained sub-porphyritic texture and distinctive orange-brown colour on both fresh and weathered surface make i t easily recognizable in the f i e l d . Quartz and euhedral sanidine crystals are commonly distributed about the rims of the vesicles. The centres are f i l l e d with calcite and rarely an unidentified mineral in radiating clusters (Plate XI). - 31 -The groundmass makes up about 90 percent of the rock and is composed of an aggregate of fine-grained sanidine, hornblende, plagioclase and quartz. The small (less than 1 mm) sanidine crystals are subhedral to anhedral. In thin section they are commonly brownish and dusty due to minor alteration. Hornblende is found as ragged crystal remnants to 1 mm. In thin section, the texture is decussate, and the hornblende is in most cases extensively altered to actinolite-tremolite, and occasionally to chlorite. Plagioclase (Ang) occurs in small laths generally less than 1 mm. in length. Alteration has been negligible and the crystallites have no preferred orientation. In addition to f i l l i n g vesicles, calcite occurs as small irregular veinlets and patches associated with epidote. Pyrite and rare chalcopyrite, which constitute less than one percent of the rock, comprise the opaque minerals. They occur as very small grains evenly disseminated throughout the rock. - 32 -Mode Mineral Percentage Hornblende (Actinolite) 27.0 Plagioclase 20.9 Sanidine 19.0 Quartz 7.6 Chlorite 12.2 Calcite, epidote 11.0 Accessories 1.0 Opaques XI.0 The vesicular nature and chilled margins of this dike suggest emplacement at a relatively high level, and at a time when the batholithic complex including the porphyries had crystallized and cooled. The relative abundance of quartz and acidic composition suggest an a f f i n i t y to the intrusives in the northwest end of the Carabine Creek Lineament which Cockfield suggests are post-Cretaceous. EXTRUSIVE ROCKS Kamloops Group Olivine Basalt On the extreme eastern edge of the property basalt is - 33 -exposed in a small bluff. Its contacts are not exposed but i t appears to overlie peridotite and altered Lobe porphyries. The rock is aphanitic, dense, with a conchoidal fracture. It is black on a freshly broken surface but weathers to a characteristic medium brown colour. It is distinctly porphyritic with rounded crystals and crystal aggregates of light brown to greenish-yellow olivine. Single phenocrysts rarely exceed 2 cm. but aggregates 5 cm. or more in diameter are common. Amygdules are rare but where present, are usually f i l l e d with white chalcedony. The rock is quite fresh with l i t t l e evidence of alteration. The olivine crystals are subangular to subrounded, moderately fractured and weakly serpentinized. Plagioclase microlites are abundant and develop trachytoid textures around the olivine phenocrysts. The composition of the plagioclase i s labradorite-bytownite (Anyg). Pyroxene occurs in very small grains and fragments and comprises most of the matrix. It is slightly altered and this, together with the small grain size, makes optical determinations d i f f i c u l t . The material f i l l i n g the vesicles has botryoidal or rounded outlines, and under crossed nichols occurs as a cockscomb aggregate. The colour is a pale brown and the r e l i e f and bire-fringence are low. On the basis of these properties, the mineral is identified as chalcedony. Mineral Olivine Plagioclase Pyroxene Chalcedony Opaques - 34 -Mode Percentage 16.0 32.0 35.0 3.0 14.0 The composition and lack of alteration indicate that this small occurrence i s in a l l probability Kamloops basalt of Miocene age. - 35 -ALTERATION In recent years significant emphasis has been placed on alteration of wallrock in porphyry copper deposits and numerous systems of classification have been proposed. A l l systems assume an excess of s i l i c a . Most intrusive species in the thesis area contain trace amounts of quartz with the exception of peridotite which is quartz deficient. Modal quartz in excess of trace amounts is present in only a few of the younger microporphyries. With this exception, the model to which the Ajax-Monte Carlo deposit may best be compared is that developed by Creasey (1966), which is based in part on ideas developed by Burnham (1962), that i s , alteration facies are defined on the basis of mineral assemblages which reflect in part leaching or metasomatic addition of basic cations. Two discernable alteration facies are present in the thesis area; a propylitic phase and a potassic phase. The propylitic phase is the earliest and most widely distributed. Intensity of propylitic alteration varies between broad limits ranging from weak, in which the only effects are joint coatings of pyrite, epidote and calcite, to intense, where the original texture of the rock is destroyed. Within the propylitic zone are two smaller areas of potassic alteration. These zones are characterized by small veinlets and fractures containing potash feldspar with trace amounts of biotite, and correspond to zones of highest sulphide concentrations. - 36 -PROPYLITIC ALTERATION The two zones of propylitic alteration (fig.14, pocket) are distinguished on the basis of alteration intensity. The eastern half of the property (designated the Eastern Zone) has been only weakly affected by the alteration processes, whereas the western half (Ajaz Zone) has been intensely altered and the igneous texture of the rocks has been largely obliterated. The boundary between the intense and weak alteration is gradational and occurs at about 12,000 E. in a region penetrated by only a few d r i l l holes. Eastern Zone This area is underlain by rocks of intermediate to acidic composition comprising the Lobe diorite and microporphyries and some peridotite, a l l of which have been weakly propylitized. Although pervasive, the alteration is not immediately apparent until observed under the microscope. In hand specimen, the diagnostic characteristics are dull white feldspars, minor concentrations of epidote near mafic minerals and coatings of epidote, pyrite and calcite on joint planes. Fracture density in the rocks, which is weak to moderate with one to ten planes per foot does not seem to have been a factor in localizing the alteration. The propylitization is pervasive and mineral gradients are not established within the altered rock adjacent to fractures. - 37 -Peridotite in this area has been extensively altered to serpentine and talc but whether or not this is the result of propylitization has not been established. The presence of fresh peridotite one-quarter mile southeast of the property suggests that these small bodies were altered subsequent to emplacement. Microscopic examinations of the Lobe porphyries from the eastern half of the property show that hornblende is altered in varying degrees to chlorite and plagioclase is altered either to extremely fine-grained sericite or to a clay mineral, probably montmorillonite. In addition, the matrix contains small irregular grains of epidote, probably formed from plagioclase. Calcite rarely is seen in thin section, though as mentioned previously, is ubiquitous in joints and fractures and suggests that the composition of the altered rocks f a l l s in the calcite-chlorite-epidote f i e l d of the ACF diagram of Creasey (1966) (Fig.3). - 38 -FIGURE (3) Compatibility diagram for propylite alteration with high CO2 pressure, s i l i c a and water in excess. From Creasey (1966) Ragged remnants of hornblende generally have been preserved but plagioclase has been completely altered and only the crystal outlines remain. In the Lobe Monzonite, plagioclase is completely altered to sericite, but primary orthoclase is unaltered. Minor epidote is present as small granules within r e l i c t plagioclase as well as in small - 39 -intergranular patches. Small quartz stringers rarely occur in the Lobe monzonite where there is modal quartz and are not observed in the other Lobe varieties. These small quartz stringers probably resulted from remobilization of quartz during alteration and not from metasomatic addition of SiO^. Ajax Zone The propylitic alteration of the Ajax zone differs in intensity and mineral assemblage from the Eastern zone. The altered area, which is about 3000 feet by 1000 feet, extends from Jacko Lake to the middle of the property. The boundaries of the propylite halo about the Ajax deposit have not been defined because alteration extends into covered areas and areas untested by d r i l l holes. The composition of the rocks prior to alteration often is d i f f i c u l t to establish because of intensity of alteration, but for the most part, the rocks appear to have been microdiorite with small quantities of the younger porphyries. Characteristically, the propylitized rocks of the Ajax zone are fine grained and massive. Destruction of primary mafic minerals has resulted in a general bleaching of the rock and the obliteration of igneous texture so the colour now is light cream, occasionally with a pale greenish cast. Brecciation of the microdiorite prior to propylitization is indicated by numerous specimens which show the irregular outlines of less altered fragments enclosed in a matrix of completely propylitized material. - 40 -The mineral assemblage developed by this phase of alteration is sodic plagioclase, commonly with sericite developed along (010) planes; epidote, ubiquitous in ragged grains and small granules; calcite, rarely in dissemminated patches but most often occurring in fractures with a selvage of epidote; and minor tremolite developed from hornblende and sphene. The presence of tremolite rather than chlorite in this zone suggests possible leaching of ferromagnesian ions concomitant with destruction of the primary mafic minerals. Quartz is rarely observed. Discussion The propylitic assemblage at the Ajax-Monte Carlo is typical of those described in the literature with the significant exception that s i l i c a , although present, is not one of the major constituents in the assemblage. Burnham (1962) states that epidote is the mineral diagnostic of the propylitic subzone, and in the Creasey model, metasomatic addition of CaO (and other basic cations as well) defines the propylitic zone. These c r i t e r i a are abundantly f u l f i l l e d in the thesis area. As shown in Figure (4) the maximum temperature for epidote st a b i l i t y ranges between 400°C at low P(H20) to greater than 600°C at high P(H20). An accurate estimate of the pressure conditions prevailing during alteration cannot be made but the hypabyssal textures of the porphyries indicates that i t was probably f a i r l y low. The - 41 -extensive alteration of peridotite to serpentine suggests a prevailing temperature below 500°C (Fig. 4), though Creasey (1966) suggests the experimental data from which this curve is derived may be inaccurate. 40 o X 30 20 3 10 400 6 0 0 Temperature * C 800 FIGURE (4) Univariant equilibrium curves for epidote and Al-serpentine. From Creasey (1966). - 42 -The alteration of plagioclase to epidote-sericite in some areas and to a clay mineral (montmorillonite?) in different areas within the propylitic zone is somewhat anomalous. A l l three minerals have been reported in propylitic alteration zones, but there is some doubt that the association montmorillonite (or kaolinite) - epidote is a stable assemblage (Creasey, 1966, Burnham, 1962). L i t t l e mention is made in the literature of the s t a b i l i t i e s of mafic minerals in the propylitic facies beyond pointing out that chlorite commonly is produced at the expense of biotite. Reference to tremolite in propylitic assemblages has not been seen by the author, but as a calcium s i l i c a t e i t s chemical composition is consistent with the requirements of this facies. Brief mention is made by Hemley (1969) of "amphiboles" present in the c h l o r i t i c alteration typical of some propylitic facies and i t is assumed that the presence of tremolite is inferred. POTASSIC ALTERATION Two zones of potassic alteration were mapped on the property (Fig. 14, pocket). The largest, the Ajax Zone, is centred on the Ajax mineral claim and w i l l be described in some detail. The smaller, less well-defined Wheal Tamar Zone w i l l be briefly described. - 43 -Ajax Zone The potassic alteration halo around the Ajax zone, on the western side of the property, is about 3500 feet in length and 1000 feet in width. In contrast to the pervasive propylitic alteration, the potassic facies is restricted to small veinlets, stockworks and fracture f i l l i n g s . Its presence was not immediately apparent in the f i e l d because the orthoclase is nearly always white; and biotite is absent from the assemblage. Potassic alteration is restricted to fractures in the propylitized rock and to envelopes up to 2 cm. wide adjacent to these fractures, and thus post-dates the propylitization. Microscopic examination of the veinlets reveals potash feldspar in a mosaic of fine interlocking grains with significant amounts of tremolite. Pyrophyllite sometimes occurs as a selvage along fracture walls and, less commonly, in the wallrock immediately adjacent to the fractures. Minor amounts of chlorite and calcite have been noted in one specimen, and their relationship to the potassic facies is not clear, but are perhaps contained within fragments of unaltered wallrock. Microcline, with i t s characteristic polysynthetic twinning and perthitic exsolution texture, together with pyrophyllite is not an uncommon constituent in the veinlets. Biotite is absent from the assemblage. Wheal Tamar Zone Potassic alteration in the Wheal Tamar zone is weak. The well-developed veinlets of the Ajax zone are not present but concentrations - 44 -of fine grains of orthoclase occur along fractures and shears (Plate XII). Biotite, pyrophyllite and quartz are absent from this zone. Discussion The potassic alteration facies displayed at the Ajax-Monte Carlo property is distinctly different from the facies described by Creasey (1966), Hemley (1969) and Burnham (1962) as typical of porphyry copper deposits. The most obvious differences are the virtual absence of biotite and the lack of abundant red or pink potash feldspar on the property. The presence of pyrophyllite is f a i r l y common at this property though i t is seldom recognized in the hydrothermally altered rocks associated with other porphyry copper. At Island Copper, on Vancouver Island, Young and Rugg (1971) mention the association of pyrophyllite with s i l i c a in fault breccias near the orebody but does not describe the assemblages developed. Creasey (1966) suggests that pyrophyllite may not be developed in a number of deposits due to high concentrations of K +ion (Fig. 5). - 45 -FIGURE (5) Some st a b i l i t y relations in the system K20 - AI2O3 - Sj02 - H2O at 15,000 psi total pressure. From Hemley (1959) The association pyrophyllite - orthoclase, which occurs in some of the veinlets in the potassic zone in the thesis area, and the absence of muscovite constitutes a non-equilibrium assemblage. Rapid fluctuations in the concentration of K +ion in the solution may have been the cause. The presence of perthite associated with potassic alteration is uncommon. Analysis of the perthite was not performed, hence i t is not possible to state a minimum temperature at which the veinlets were deposited. However, the pyrophyllite-kaolinite dehydration curve, which i s independent of pressure, (Fig. 6) suggests prevailing temperatures - 46 were in excess of 350°C. P»' x ier 24 20 16 12 < 300 600 900 Tempera ture FIGURE (6) Experimental dehydration curves for the sta b i l i t y limits of kaolinite, Al-montmorillonite, and pyrophyllite. From Creasey (1966) - 47 -STRUCTURE The phases comprising the Iron Mask Batholith may have been emplaced intermittently along the Carabine Creek Lineament. Recurring tectonic adjustment and concomitant passive emplacement of magma at depths which became increasingly shallower as the emplacement of the batholith proceeded are suggested by the f i e l d relationships of the various phases. After the coarse-grained phases had crystallized, extensive brecciation occurred along a zone on the northern margin of the property. At least one and possibly two episodes of fracturing preceeded the rock alteration and mineralization was emplaced along s t i l l later sets of fractures. Carr (1956) states that the peridotite body at the Iron Mask Mine is fault-bounded, and infers similar relationships for other peridotites associated with the batholith. Peridotites at the Ajax-Monte Carlo property are not sufficiently exposed to permit comment on their boundaries with adjacent rocks. Three phases of fracturing have been observed on the property. The earliest formed a breccia zone which developed prior to the emplacement of the microdiorite. The second, involving the rocks of intermediate composition was synchronous with the alteration of these rocks and provided the necessary permeability for alteration. The fin a l phase developed the stockwork within the altered rock in which the sulphides and associated gangue minerals were deposited. - 48 -Phase I Fracturing - The Ajax Breccia The dominant structural feature is a breccia zone on the northern edge of the property which occupies the position of the contact between the coarse crystalline rocks of the Iron Mask Batholith to the north and the finer grained younger intrusive types to the south. Gabbro or pyroxenite and rare diorite fragments are cemented by a matrix of microdiorite. The character of the breccia changes over a distance of about 1000 feet from predominantly fragments (95%) on the north in the coarsely crystalline rocks of the batholith to predominantly matrix (95%) with occasional isolated fragments of gabbro to the south (Fig. 15). In most cases, there has been l i t t l e , i f any, assimilati on of the fragments, but occasionally there are zones within the breccia in which the fragments have been partially digested and outlines of individual fragments are d i f f i c u l t to discern (Plate II). Most fragments are angular to sub-angular. In one outcrop near the eastern corner of the Ajax claim the fragments are sub-rounded to well-rounded and exhibit l i t t l e or no evidence of assimilation (Plate XIV). The chronological time of brecciation may be placed with accuracy relative to the rock types involved. The coarse-grained rocks were emplaced and s o l i d i f i e d before brecciation and intrusion of microdiorite. It seems probable that continued stress along this portion of the Carabine Creek lineament was released along the approximate contact between the coarse-grained rocks of the batholith and the Nicola volcanics. Dilation of the breccia zone allowed the emplacement of microdiorite which forms - 49 -the breccia matrix, and the Lobe porphyries. Absence of fragments of Nicola rocks in the breccia suggest the brecciation occurred entirely within the batholithic rocks. Phase II Fracturing - Synchronous with Alteration Subsequent to the intrusion and crystallization of the microdiorite and Lobe diorite, another episode of fracturing occurred which opened channels for the altering solutions. Intermittent stress releases throughout the alteration history are indicated by wispy, ghost-like fragments of moderately propylitized microdiorite in a matrix of porcelaneous " a l b i t i t e " . Occasionally,:the fragments have sharp boundaries with the a l b i t i t e which suggests fracturing during the propylitic alteration episode. Fracturing following propylitization is indicated by the development of potassic alteration minerals in openings in propylitized rock. Veinlets containing minerals of the potassic assemblage invariably cut propylitized microdiorite and Lobe porphyries. Sulphides are absent from the Phase II fractures. Phase III Fracturing - The Sulphide-Bearing Stockwork Fractures of the Phase III group cut Phase I and Phase II fractures. Sulphides and calcite, the dominant minerals in the assemblage which f i l l s Phase III fractures weather readily making the fractures easily recognizable in outcrop. Copper carbonates and limonite are common at or near surface in the Ajax, Monte Carlo and Wheal Tamar zones, but away from these mineralized areas, pyrite, epidote and calcite are - 50 -typical fracture f i l l i n g s . The intensity of Phase III fracturing is greatest within the Ajax Zone where locally the altered rock as been shattered into 1 inch fragments. The stockwork of fractures appears to be centred about the zone of most intense alteration in the v i c i n i t y of the underground workings, which suggests that the alteration rendered the rock more susceptible to b r i t t l e failure, or that this zone was a focus of intermittent stress release. A plot of 182 poles to Phase III fractures on a Schmidt equal-area stereonet shows that the fractures occur in three steep-dipping sets. The direction of the dominant set is 002° and subordinate sets occur at 130° and 147°. The chronology of fracturing is d i f f i c u l t to establish within the Phase III group because of the intensity of fracturing, and results are ambiguous. In the Ajax south adit (Fig. 8), the earliest fractures trend northeasterly and dip moderately to the northwest (A') or southeast (A). These are cut by a set which trend northwest and dip moderately northeast (B), which in turn are post-dated by fractures which trend north-south and dip easterly (X) and by a set of fractures which trend northwesterly and dip steeply to the northeast or southwest (Y). Secondary mineralization appears to be concentrated in the earlier fractures (A, A' and B). In the Ajax north adit (Fig. 9) the chronology of fracturing is similar, with the oldest sets trending northeast with moderate - 51 • > 5 % PER 1% AREA • > 4 % PER 1%AREA • > 3 % PER l % A R E A • > I % PER I % AREA 182 POINTS FIGURE 7 POLES TO PHASE III FRACTURES LOWER HEMISPHERE PROJECTION - 52 -northwestward dips (A 1) and trending northwest with moderate north-easterly dips (B). Cutting these are east-west striking, north dipping fractures (D), steep north striking fractures (E). In the p i t over the south Ajax adit (Fig. 10), early northeast-trending fractures (A and A') contain secondary mineralization and are cut by a north dipping, north-west striking set (F) and a north-south set (X). The shallow shaft on the Wheal Tamar zone (Fig. 11) permite the only three dimensional look at the structure in this area. The earliest Phase III fractures displayed here are steep-dipping and strike northerly (E) or slightly east of north (A?, A). These are related to the dominant set of fractures in figure (7). Sets striking northeasterly with steep (A?) or moderate (C) southeast dips are displaced by the steep northwest trending shear (Y). Fractures (A, A?, C) of the dominant set, then, appear to predate fractures (Y) of a subordinate set. The Monte Carlo shear zone (Fig. 12) was explored in the 1920's by a shallow adit, test p i t, and by three d r i l l holes. The adit is caved and the information presented herein was derived from the original records. The zone intersected in the crosscut consists of three shears each 10 to 15 feet wide. D r i l l i n g and test pitting to the south has established that the shears strike northerly and dip steeply westward. As such, they are the same attitude as the dominant set of Phase III fractures in figure 6. - 53 ->B S C A L E I -- 10 f \ F SYMBOLS - v w v SHEAR ZONE FAULT WINZE PRIMARY 8 / O R SECONDARY MINERALIZATION F I G U R E 8 S O U T H A D I T A J A X Z O N E L A T 8 8 8 0 L O N G 10 2 2 0 - 54 -S C A L E I 10' SYMBOLS < w w SHEAR Z O N E , F A U L T "WW PRIMARY 8 / OR SECONDARY MINERALIZATION FIGURE 9 NORTH ADIT AJAX ZONE LAT 9030 LONG 10,380 - 55 -SCALE I " = 10' SYMBOLS FAULT PRIMARY 9 / OR SECONDARY MINERALIZATION SLICKENSIDES FIGURE 10 PIT OVER SOUTH ADIT AJAX ZONE LAT 8880 LONG 10 ,220 - 56 -SYMBOLS SHEAR ZONE PRIMARY a / OR SECONDARY MINERALIZATION FAULT FIGURE 11 WHEAL TAMAR SHAFT LAT. 9920 LONG. 13 580 - 57 -The limited exposures on the property do not permit an accurate picture of the chronology of fracturing to be developed beyond the general and somewhat ambiguous ideas presented here. It is evident, however that fractures of the Phase III group were not generated simultaneously in a simple stress f i e l d . - 59 -MINERALIZATION The main concentration of mineralization occurs in the Ajax Zone with lesser amounts in the Wheal Tamar Zone and in the Monte Carlo shear. The Ajax mineralization is localized within zones of anastomosing fractures belonging to the Phase III group which form short, irregular shoots. Minor amounts of sulfide occur as disseminations throughout the rock in the Ajax Zone but most is restricted to the stockwork of narrow fractures and veinlets. The Wheal Tamar mineralization is restricted mainly to shear zones. Minor amounts of sulfides are disseminated throughout the rock, usually as replacements of mafic minerals. Shear zones are a l l steeply dipping, and have no discernable preferred orientation. Diamond d r i l l evidence suggests that the zones are short and discontinuous, or have been displaced along post-mineral faults, because of a lack of correlation between d r i l l holes two hundred feet or so apart. The Monte Carlo shear is a well-defined, though short zone, which dips steeply westwards and strikes northerly. Underground workings which intersected the shear zone indicate a width of 60 feet. Three mineralized shoots, each about 10 feet wide and grading about one percent copper, occur within the shear zone. Because the adit is caved, further information regarding the nature of the mineralization is not available. - 60 -PRIMARY MINERALS The mineralogy of the mineral deposits is very simple, with only a few species present. They are described in order of abundance. Magnetite Magnetite, the only primary oxide mineral on the property, occurs as an accessory mineral in disseminated grains and patches to 1 cm. in the Iron Mask Gabbro. Generally magnetite constitutes less than 10 percent of the rock, but rarely i t is localized in lenses a few feet long and a few inches wide in shears in highly altered gabbro. In peridotite i t occurs as small euhedral grains in a matrix of serpentine adjacent to remnants of crystals of olivine. The Lobe monzonite also contains trace amounts of magnetite, in euhedral grains to 0.1 mm. Pyrite Pyrite is typically found in the younger intrusive rocks on the property, the most common hosts being microdiorite and Lobe diorite. It seldom occurs in concentrations exceeding 3 percent and, in contrast to other porphyry copper deposits, which have pyrite-rich zones or aureoles, i t is evenly distributed throughout the property. In the Ajax Zone, i t occurs as anhedral to irregular grains up to 1 mm. in diameter in phase III fractures, accompanied by chalcopyrite. In the eastern half of the property, where chalcopyrite is absent, pyrite occurs as small subhedral or euhedral grains with epidote and calcite in Phase III fractures. - 61 -Chalcopyrite Chalcopyrite is the dominant copper mineral found in the map area. The highest concentration is in the Ajax Zone where i t occurs predominantly in Phase III fractures in altered microdiorite and Lobe diorite. Polished section study reveals chalcopyrite in small inter-s t i t i a l grains and extremely irregular patches within fractures, and often as disseminated grains (0.01 mm.) along hairline fractures and mafic mineral-feldspar grain boundaries in the adjacent rock. In the Wheal Tamar Zone, chalcopyrite occurs in shear zones with bornite but without the usual gangue minerals calcite, epidote and chlorite. Texturally i t is similar to the chalcopyrite in the Ajax Zone, except for a tendency towards orientation along shear direction in deformed mafic patches. Bornite Traces of bornite have been observed in polished sections of cores from the Ajax Zone in close association with chalcopyrite in Phase III fractures. Where observed, the bornite has been in contact with chalcopyrite and may be an exsolution product. However, definitive textures have not been observed. Bornite is relatively more abundant in narrow shears in the Wheal Tamar Zone, but nowhere on the property does i t reach concentrations of economic importance. Gold Persistent assays of gold in the order of 0.01 oz. per - 62 -ton are obtained from oxide zones in the Wheal Tamar, Ajax and Monte Carlo mineralized areas. Free gold has not been seen in hand specimens or polished sections. SECONDARY MINERALS Although weathering has been extensive, expecially in the more highly fractured and permeable Ajax, Monte Carlo and Wheal Tamar Zones, leaching and removal of copper has been minimal. Abundant calcite rapidly fixed copper ions as malachite and azurite. These stable carbonates, together with abundant limonite constitute the bulk of the secondary mineral suite. Because the region is semi-arid and because of the tendency for copper to become rapidly fixed as carbonates, a leached capping is poorly developed and there is virtually no zone of supergene enrichment. Consequently minerals typical of the oxide and supergene zones such as native copper, cuprite and chalcocite are not found on the property. The depth of surface weathering is a function of the permeability and thus of the fracture density. In some of the weakly mineralized zones on the property the rock is oxidized to a depth of 25 feet to 30 feet, but on the Ajax Zone, where Phase III fracturing is intense, limonite and copper carbonates have been observed in cores at depths of 250 feet. - 63 -CONCLUSIONS The intrusive history of the property reflects the large scale events which have characterized the development of the Carabine Creek Lineament and the Iron Mask Batholith. Development of the intrusive complex was initiated by the emplacement of the plutonic-textured core rocks comprising the Iron Mask gabbro and diorite in folded Nicola Group volcanics. Uplift and unroofing then followed. Tectonic adjustments were accommodated by zones of weakness along the contacts between the r i g i d core and the enclosing country rock, creating the Ajax breccia and allowing the emplacement of the microdiorite, micromonzonite and porphyritic species. Intermittent stress releases of small magnitude continued along the predefined zones of weakness resulting in brecciation of the microdiorite and Lobe porphyries to create the Phase II stockwork. Development of the alteration zones was synchronous with the Phase II fracturing. Propylitization was pervasive and predates the potassic alteration which was restricted to fractures in the propylitized rock. The propylitic assemblage developed at the property is characterized primarily by chlorite, calcite and epidote and except for a lack of abundant s i l i c a , i s typical of porphyry copper deposits. By comparison, the potassic alteration assemblage is distinctly different from those described in the literature. Biotite and red orthoclase are both rare, - 64 -and the facies i s characterized by pyrophyllite, white orthoclase with minor perthite and quartz. The relative scarcity of quartz reflects the low concentrations of free s i l i c a in the host rocks. Fracturing of the altered rock to form the Phase III mineralized stockwork does not appear to have been the result of a single episode of dislocation. The chronology of Phase III fracturing was not established, however i t does appear that the earliest fractures are north-dipping and strike north easterly or northwesterly. These are cut by younger fractures of various attitudes. Sta t i s t i c a l l y , steep north-striking fractures dominate the Phase III stockwork, however, as shown on the stereonet plot of Phase III fractures. Displacement of the mineralized shears by subsequent faults is indicated by relationships in the Ajax south adit. As a consequence, the size, shape and spatial relation-ships of the mineralized zones is indeterminate from the available data. - 65 -BIBLIOGRAPHY 1. Allen, J.M. and J. Richardson (1970); The Geological Setting of the Valley Copper Orebody; Paper presented to the C.I.M.M., Annual Meeting in Toronto. 2. Barnes, H.L., and G.K. Czamanske, (1967); Solubilities and Transport of Ore Minerals; in Geochemistry of Hydrothermal Ore Deposits. Ed. H.L. Barnes, p.p. 334-385. 3. Bryner, L., (1961); Breccia and Pebble Columns Associated with Epigenetic Ore Deposits; Ec. Geol. v. 56, p.p. 488-508. 4. Burnham, C.W., (1962); Facies and Types of Hydrothermal Alteration Ec. Geol. v. 54. 5. Campbell, R.B. and H.W. Tipper (1970); Geology and Mineral Exploration Potential of the Quesnel Trough, British Columbia; C.I.M. Trans, vol LXIII, p.p. 174-179. 6. Carr, J.M., (1956); Deposits Associated with the Eastern Part of the Iron Mask Batholith Near Kamloops; in B.C. Minister of Mines Ann. Rept., p.p. 47-69. 7. Carr, J.M., (1960); Porphyries, Breccias and Copper Mineralization in Highland Valley, B.C.; Can. Min. Jour., p.p. 71-73. 8. Cockfield, W.E., (1948); Geology and Mineral Deposits of the Nicola Map Area, British Columbia; Geological Survey of Canada, Mem. 249. 9. Creasey, S.C., (1959); Some Phase Relations in The Hydrothermally Altered Rocks of Porphyry Copper Deposits; Ec. Geol. vol. 54. 10. Creasey, S.C., (1966); Hydrothermal Alteration; in Geology of the Porphyry Copper Deposits, Southwestern North America. Ed. S.R. Titley and C L . Hicks, p.p. 51-74. 11. Daly, R.A., (1912); Memoir 68, Golden to Kamloops, Geological Survey of Canada. 12. Dawson, G.M., (1894); Annual Report, The Kamloops Map Sheet, Geological Survey of Canada. - 66 -13. Drummond, A.D., and E.T. Kimura (1968); Hydrothermal A l t e r a t i o n at Endako Mines - A Comparison to Experimental Studies; Paper presented to the Annual Meeting of the C.I.M.M., Vancouver, B.C. 14. Fournier, R.O., (1967); The Porphyry Copper Deposit Exposed i n the L i b e r t y Open-Pit Mine near Ely, Nevada; Ec. Geol. v. 62, p.p. 57-81 and 207-221. 15. Hemley, J . J . (1959); Some Mineralogical E q u i l i b r i a in the System K 20 -p.p. 241-270  A l ^ - S i 0 2 - H 20; Am. J . Sec. 257, 16. Hemley, J . J . and W.R. Jones (1964); Chemical Aspects of Hydrothermal A l t e r a t i o n with Emphasis on Hydrogen Metasomatism; Ec. Geol. v. 59. 17. Jones, R.E., (1957); Geological Report on the D.M. Group of Claims, Kamloops M.D.; Unpub. Assessment Report on open f i l e - Kamloops Mining Recorder. 18. Kents, P., (1964); Special Breccias Associated with Hydrothermal Developments i n the Andes; Ec. Geol. v. 59, p.p. 1551. 19. Leary, G.M., (1970); Petrology and Structure of the Tuzo Creek Molybdenite Prospect, near Penticton, B.C.; Unpub. M.Sc. Thesis, Univ. of B.C. 20. Livingston, D.E., (1968); Geochronology of Emplacement, Enrichment and Preservation of Arizona Porphyry Copper Deposits; Ec. Geol. v. 63, p.p. 30-36. 21. Livingston, E., (1959); Combined Geological and Geophysical Report on the Fat Chance Claims, Knutsfor, B.C.; Unpub. Assessment Report, on open f i l e at the o f f i c e of the Kamloops, B.C. Mining Recorder. 22. Lowell, J.D., and J.M. Guilbert (1970); Lateral and V e r t i c a l A l t e r a t i o n - Mineral Zoning i n Porphyry Copper Deposits; Ec. Geol. v. 65. 23. Mathews, W.H., (1941); Geology of The Iron Mask Batholith; Unpub. M.A.Sc. Thesis, Univ. of B.C. 24. Meyer, C , and J . J . Henley, (1959); Hydrothermal A l t e r a t i o n in Some Granodiorites; i n Clays and Clay Minerals, Proc. 6th Conf. on Clays and Clay Minerals, Berkely, C a l i f . , 1957. - 67 -25. Ney, C.S., (1966); D i s t r i b u t i o n and Genesis of Copper Deposits in B r i t i s h Columbia; C.I.M.M. Spec. Vol. No. 8, p.p. 295-304. 26. Nielsen, R.L., (1968); Hypogene Texture and Mineral Zoning i n a Copper-Bearing Granodiorite Porphyry Stock, Santa Rita , New Mexico; Ec. Geol. v. 63, p.p. 37-50. 27. Northcote, K.E., (1969); Geology and Geochronology of the Guichon Creek L a t h o l i t h ; B.C. Dept. of Mines and Pet. Res. B u l l . 56, p. 73. 28. Perry, V.D., (1961); The Sig n i f i c a n c e of Mineralized Breccia Pipes; A.I.M.E. Trans., v. 220, p.p. 216-226. 29. Preto, V.A.G., (1967); Geology of the Eastern Part of the Iron Mask Batholith; i n B.C. Minister of Mines Ann. Rept. p.p. 137-144. 30. Preto, V.A.G., (1968); Report on Kimberley Copper Mines Ltd. Kamloops M.D.; i n B.C. Minister of Mines Ann. Rept. p.p. 169-172. 31. Rose, A.W., (1970); Zonal Relations of wallrock A l t e r a t i o n and Sulphide D i s t r i b u t i o n at Porphyry Copper Deposits; Ec. Geol. v. 65, p.p. 920-936. 32. Schau, M.P., (1964); Geology of the Upper T r i a s s i c Nicola Group in South Central B r i t i s h Columbia; Unpub., Ph.D. Thesis, Univ. of B.C. 33. Turner, F.J. and Weiss, L.E., (1963); Structural Analysis of Metamorphic Tectonites; McGraw H i l l Book Co. 34. Young, M.E. and Rugg, E.S., (1971); Geology and M i n e r a l i z a t i o n of the Island Copper Deposit; i n Western Miner, Vol. 44, No. 2. - 68 -PLATES PLATE I IRON MASK GABBRO (x-6) Note the ophitic texture, and hematite (red) after magnetite. PLATE II AJAX BRECCIA (X-%) Fragments of Iron Mask Diorite in Microdiorite matrix. - 69 -PLATE IV PERIDOTITE (X-l) Core speciman displaying fragments of porphyritic material in a finer groundmass. - 70 -PLATE V PERIDOTITE (X-15) Vestigal Olivine (ol) crystals in an aureole of serpentine (s). Euhedral magnetite and pigeonite (p) in glass matrix. PLATE VI LOBE DIORITE (X-6) - 71 -PLATE VII LOBE DIORITE PORPHYRY (X-6) Subtrachytoid texture. - 72 -PLATE IX LOBE MONZONITE (X-6) Specimen has been stained with cobaltinitrate. Note fragments of Microdiorite and Lobe Diorite. PLATE X MICROMONZONITE (X-6) Specimen is a small dike intruding Microdiorite. - 73 -PLATE XII POTASSIC ALTERATION - WHEAL TAMAR ZONE (X-6) Specimen has been stained with cobaltinitrate to reveal small fracture. - 74 -PLATE XIII AJAX BRECCIA Fragments of Iron Mask Gabbro in Microdiorite. Ajax Zone. Knife in photo centre for scale. PLATE XIV AJAX BRECCIA (X-l) Fragment of Iron Mask Gabbro in strongly propylitized Microdiorite. - 75 -PLATE XV WHEAL TAMAR ZONE Looking westwards toward Ajax Zone behind Lone Pine H i l l . PLATE XVI AJAX NORTH ADIT LU O o o o UJ • o o u 1 0 0 0 0 N 9 5 0 0 N 9 0 0 0 N 8 5 0 0 N 8 0 0 0 N SYMBOLS A A A A O U T C R O P INTRUSIVE C O N T A C T - DEFINITE I N T R U S I V E C O N T A C T - A S S U M E D DIAMOND D R I L L H O L E S H A F T T R E N C H ADIT DUMP S W A M P . , T R E A M P R O P E R T Y B O U N D A R Y A J A X B R E C C I A • < VJJ OC tr UJ O- 2 i...r J A C K O P O R P H Y R Y M I C R O M O N Z O N I T E S U G A R L O A F P O R P H Y R I E S L O B E D I O R I T E , L O B E M O N Z O N l T E V A R I E T I E S M I C R O D I O R I T E C O A R S E C R Y S T A L L I N E S U I T E I R O N M A S K DIORITE IRON M A S K G A B B R O PRE INTRUSIVE R O C K S N I C O L A G R O U P FIGURE 1 3 G E O L O G Y AJAX - MONTE CARLO . COPPER PROPERTY BRITISH COLUMIA S C A L E I " = 3 0 0 ' 200 400 T P A C C O M P A N Y T H E THESIS " G E O L O G Y OF T H E A J A X - M O N T E C A R L O C O P P E R P R O P E R T Y B Y WW P A R M S T R O N G I 9 73 ) 8000 N SYMBOLS A "I A A A O U T C R O P INTRUSIVE C O N T A C T - DEFINITE INTRUSIVE C O N T A C T - A S S U M E D DIAMOND DRILL H O L E S H A F T T R E N C H ADIT DUMP SWAMP S T R E A M P R O P E R T Y B O U N D A R Y A J A X B R E C C I A P R O P Y L I T I C A L T E R A T I O N F A C I E S P O T A S S I C A L T E R A T I O N F A C I E S 2 10 y < < DP IZI y UJ or CL Z L E G E N D POST INTRUSIVE ROCKS K A M L O O P S G R O U P INTRUSIVE ROCKS R H Y O L I T E P E R I D O T I T E , S E R P E N T l N l T E J A C K O P O R P H Y R Y M I C R O M O N Z O N I T E S U G A R L O A F P O R P H Y R I E S L O B E D I O R I T E , L O B E M O N Z O N l T E V A R I E T I E S M I C R O D I O R I T E C O A R S E C R Y S T A L L I N E S U I T E I R O N M A S K DIORITE IRON M A S K G A B B R O PRE INTRUSIVE R O C K S N I C O L A G R O U P FIGURE 14 ALTERATION AJAX - MONTE CARLO COPPER PROPERTY BRITISH S C A L E COLUMIA I " = 300' 200 400 T O A C C O M P A N Y T H E THESIS " G E O L O G Y OF T H E A J A X - M O N T E C A R L O C O P P E R P R O P E R T Y B Y W-M P A R M S T R O N G 1973 ( SECTION A A SOUTHWEST A J A X Z O N E NORTHEAST ELEVATION 3IOO 2800 2500 SOUTHWEST NORTHEAST S E C T I O N B B W H E A L T A M A R Z O N E ELEVATION 3100 28 OO 2 5 0 0 A A A A A A A A A A A A > ~ / V A A A A A A A A A A* A A ^ A A A A A A A A A T A A A f A A A ^ A p A A A i A A A A 2 2 0 0 A A A A A S Y M B O L S INTRUSIVE CONTACT - DEFINITE INTRUSIVE CONTACT - ASSUMED DIAMOND DRILL HOLE INTERSECTION OF DRILL HOLE WITH SECTION BRECCIA fe s 8 5 I < < a rr LJ r- Z ? 2 ' < ui rr or ui o- z 1 8 L E G E N D P O S T INTRUSIVE R O C K S KAMLOOPS GROUP I N T R U S I V E R O C K S RHYOLITE PERIDOTITE , SERPENTINITE J\ACKO PORPHYRY MICROMONZONITE SUGARLOAF PORPHYRIES LOBE DIORITE, LOBE MONZONITE VARIETIES MICRODIORITE COARSE CRYSTALLINE SUITE IRON MASK DIORITE IRON MASK GABBRO P R E I N T R U S I V E R O C K S NICOLA GROUP FIGURE 15 S E C T I O N S A A ond B B A J A X M O N T E C A R L O COPPER P R O P E R T Y BRITISH COLUMBIA SCALE I " - 300' TO ACCOMPANY THE THESIS " GEOLOGY OF THE AJAX MONTE CARLO COPPER PROPERTY BY WM.P ARMSTRONG 1972 

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