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TitleEarly to middle Pleistocene Arctic coastal ice caps in the Northern Interior Plains of Canada, a comparison with northeastern Siberian coastal uplands
AuthorDuk-Rodkin, A; Barendregt, R W; Velichko, A A; Galloway, J M; McNeil, D
Source PP13B-2109, 2012, 1 pages
LinksOnline - En ligne
Year2012
Alt SeriesNatural Resources Canada, Contribution Series 20170154
PublisherAmerican Geophysical Union
MeetingAmerican Geophysical Union, Fall Meeting; San Francisco; US; December 3-7, 2012
Lang.English
Mediapaper; on-line; digital
File formathtml
ProvinceNunavut; Northern offshore region
AreaNorthern Interior Plains; Siberia; Russian Federation; Canada
Subjectspaleomagnetism; macrofossils; fabric analysis; till fabric; glacial deposits; glacial landforms; glaciers; glaciation; glacial stages; interglacial stages; Matuyama Chron; Gauss Chron
AbstractA stratigraphic record of four to five ice-cap developments during the last 2.6 myr was discovered along the Northern Interior Plains (NIP) of the Canadian Continental Arctic Coast below 500 m elevation. Paleomagnetism, macrofossils, foraminifera, till fabrics and pebble lithologies were obtained from outcrops. This glacial stratigraphic record is less extensive than that found west of the continental divide in the Northern Canadian Cordillera, where at least 11 glaciations occurred in the last 2.7 Ma and where uplift along the south side of NW North America during the Pliocene set the stage for large scale glaciations. These coastal mountains and the continental divide created a double rain shadow effect that limited Pacific moisture reaching the NIP. East of the continental divide, moisture supply was only sufficient to form valley glaciers in five of the glacial periods that affected the Cordillera. The NIP was also affected by five glaciations. Ice-caps developed periodically and in the late Pleistocene, the Laurentide Ice Sheet covered all of the NIP. During interglacial times, the NIP experienced dry steppe conditions, similar to modern northern climates found in regions of extreme continentality. The geographic setting along the eastern Siberian coast is comparable to conditions of the NIP, but no record of glaciations exists from upland areas near the Arctic Ocean. Moisture supply and temperature were likely insufficient to form local ice caps at low coastal elevations (<600 m) during the Pleistocene; only in the mountains to the south did glaciers form. Climatic conditions leading to the formation of ice-caps in the NIP may be related to local influences, such as an open or partially open Arctic Ocean. Ice caps may have formed during interglacial times when warm waters periodically entered the Arctic Ocean. There is sufficient data linking marine life from the Bering Sea to western Canadian Arctic to support the idea that warm waters from the NE Pacific reached the coast of the NIP, thus providing sufficient moisture for the development of ice-caps during interglacials. In contrast, in eastern Siberia, a triple "rain shadow effect" formed by the Chersky, Suntar-Khayta, and Momsky ranges precluded moisture-bearing air originating from the Sea of Okhotsk to reach the Arctic Ocean. The absence of ice-caps here seems to indicate a frozen Arctic Ocean during most of the Pleistocene. Large scale glaciations (e.g., Cordilleran ice sheets) commenced in NW North America in the late Gauss Chron (Pacific Ocean influence), in Europe during the late Matuyama Chron (Atlantic Ocean influence), and in Siberia during the middle to late Brunhes Chron (Okhotsk Sea influence). In the last million years in Europe (including Russia), glaciations occurred more frequently than in North America, suggesting significant differences in the factors that drive continental versus local glaciations in NW Canada/Alaska and Europe.
GEOSCAN ID305380