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• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Canada; canada basin; Chukotka; Alaska; Siberia
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.563.3477; http://alaska.usgs.gov/staff/geology/bradley/pubs/2000_Dumoulin_Arctic_cono_biogeog.pdf

Summary: Differences in lithofacies and biofacies suggest that lowcr Paleozoic rocks now cxposed in Arctic Alaska and the Canadian Arctic Islands did not form as part of a single depositional system. Lithologie contrasts are noted in shal-low- and deep-watcr strata and are especially marked in Ordovician and Silurian rocks. A widespread intraplatform basin of Early and Middle Ordovician age in northern Alaska has no counterpart in the Canaelian Arctic, anel the regional drowning anel backstepping of the Silurian shelf margin in Canaela has no known parallel in northern Alaska. Lower Paleozoie basinal facics in northern Alaska are chiefly silieiclastic, whereas resedimented carbonates are volumetrieally important in Canada. Miero- anel maerofossil assemblages from northern Alaska contain elements typical of both Sibcrian anel Laurentian biotie provinees; co-eval Canaelian Aretie assemblages contain Laurentian forms but lack Siberian species. Siberian affinities in northern Alaskan bioras persist from at least Mielellc Cambrian through Mississippian time anel appear to decrease in intensity frorn present-day west to east. Our lithologie anel biogeographie data are most eom-patible with the hypothesis that northern Alaska-Chukotka formed a discrcte tectonic block situateel between Siberia anel Laurentia in early Paleozoie time. If Arctic Alaska was juxtaposeel with the Canaelian Arctie prior to opening of the Canada basin, biotic constraints suggest that such juxtaposition took place no earlier than late Palcozoie time.