ARCTIC Marine Events of the Beaufort-Mackenzie Basin and Correlation.igocene to Pliocene Marine Outcrops in Arctic North America’
ABSTRACT. The benthic foraminiferal succession from the Beaufort-Mackenzie Basin of arctic Canada reflects many of the major oceanographic and climatic events of the Tertiary. The Paleocene-Eocene epochs are characterized by restricted marine circulation a d pronounced foraminiferal endemism. Paleog...
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| Language: | English |
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1989
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.560.8125 http://pubs.aina.ucalgary.ca/arctic/Arctic43-4-301.pdf |
| Summary: | ABSTRACT. The benthic foraminiferal succession from the Beaufort-Mackenzie Basin of arctic Canada reflects many of the major oceanographic and climatic events of the Tertiary. The Paleocene-Eocene epochs are characterized by restricted marine circulation a d pronounced foraminiferal endemism. Paleogeographic reconstruction illustrates that the Paleocene-Eocene Arctic Ocean was markedly different from its modem counterpart and it is thus referred to as the “Arctic Gulf. ” Marine connections between the Arctic and Atlantic oceans were broadened and deepened during the Oligocene. The Arctic Gulf thus evolved into a modern Arctic Ocean configuration by sea floor spreading in the Greenland-Norwegian Sea. The Oligocene index, llrrrilina akatica Andreae, appeared in the arctic regions concurrent with increased circulation between the North Atlantic and Arctic oceans. In the Beaufort-Mackenzie subsurface, llrrrilina akatica has proven to be a widespread and reliable zonal index. In outcrop, it is known from only one locality, the Nuwok Member of the Sagavanirktok Formation on Carter Creek, Alaska. During the Miocene, increased circulation between the Arctic and Atlantic oceans was further established, and a moderate warming trend developed after a cool early Oligocene episode. The foraminifer Asterigerina staeschei (Franke) is an abundant and widespread marker of this phase of arctic marine history. Asterigerina staeschei became extinct in the middle Miocene in both the arctic and North Atlantic regions. In the Beaufort-Mackenzie Basin, many associated species ranged through into the late Miocene but disappear abruptly at the terminal Miocene unconformity. Major faunal and depositional sequence changes mark this as one of the most significant events in arctic Tertiary history, and the unconformity itself was caused by a widespread relative drop in sea level. |
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