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Glacio-marine foraminifera of British Columbia and Southeast Alaska

University of British Columbia

Foraminifera are described from massive, unconsolidated glacio-marine deposits probably of late Pleistocene age from the coast of British Columbia and southeast Alaska. Twenty families, 44 genera, and 102 species are recorded. The species Bolivina alexanderensis and the varieties Fissurina marginata (Montagu) var. juneauensis and Oolina collaris (Cushman) var. howensis are described as new. The Foraminifera lived in shallow water (less than 30 meters), which was cold (possible range -2°C to summer maxima of 25°C) and of variable salinities from brackish to normal marine (approximately 15°/oo to 35 /oo), with salinity at Lakelse having been the lowest. This work in combination with that of others demonstrates the existence of a foraminiferal province in high latitudes of the northern hemisphere in cold, shallow, coastal waters of brackish to normal marine salinities throughout Quaternary time. This province is notable for its wide geographic extent around North America and Eurasia. Samples studied are from the vicinities of Vancouver and Lakelse and Graham Island, British Columbia and Juneau, Alaska. Specimens were obtained from deposits at elevations from near sea level to several hundred feet above present sea level; isostatic rebound following ice load removal and local uplift along faults probably caused the present elevated exposures. The sediments consist mainly of clasts of heterogeneous grain size (clay to boulder) which rained down into near-shore marine waters from melting glacial ice. As well as Foraminifera and other marine fossils, much woody plant material occurs in the sediment. A presumably similar sedimentation pattern was observed occurring in Taku Inlet, Alaska. Shell casts in many outcrops investigated indicate marine origin of the sediment though weathering has advanced too far for retention of tests of Foraminifera. Similar deposits doubtless are widespread along the British Columbia and southeast Alaska coast and extend some distance south into the state of Washington and further north along the Alaska coast, as well as being present elsewhere in North America and Eurasia.

Text

2011-09-07

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http://hdl.handle.net/2429/37169

Geological Sciences

University of British Columbia

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