Cretaceous Paleogeography of Arctic Canada: ABSTRACT

Abstract

In Early Cretaceous time Berriasian-Valanginian boreal seas covered North Yukon and Sverdrup basins and were connected at the site of the present Beaufort Sea. Dawson City strait connected the North Yukon sea with the North Pacific sea of the Saint Elias trough across the present Klondike plateau. The remainder of Arctic Canada was dry land. In latest Valanginian time, uplift excluded the Hauterivian-Barremian seas from Sverdrup basin but North Yukon basin and Dawson City strait remained flooded after partial, early Hauterivian regression. An Aptian boreal transgression flooded the Sverdrup basin and restored direct connection with the North Yukon sea which subsequently spread eastward into Darnley Bay and lower Peel River areas. Aptian orogeny closed the Dawson City strait and separated permanently the Canadian Boreal and North Pacific seas. The early and middle Albian boreal seas covered Sverdrup and North Yukon basins and most of Mackenzie Lowlands and Mountains but late Albian and Cenomanian seas were restricted to a residual seaway east of Mackenzie River that connected the Mowry sea with that of Sverdrup basin. An early Turonian transgression flooded the present regions of northern Yukon, Mackenzie Mountains, and, possibly, the Sverdrup basin; its total extent is still obscure. In the late Turonian the sea left the Mackenzie Mountains region but the North Yukon and Sverdrup basins remained flooded and were connected with a residual seaway east of Mackenzie River. A new seaway, connecting Sverdrup basin with the West Greenland sea across Ellesmere Island and Baffin Bay, opened in the late Turonian. The most extensive flooding of Arctic Canada was caused by the Coniacian to mid-Santonian transgression which covered the areas of the Mackenzie Mountains, North Yukon basin, and Sverdrup basin, and extended east as far as Coppermine River. Strong late Santonian uplifts on the west side of the Mackenzie Lowlands were followed by a series of increasingly intense uplifts that caused progressive eastward retreat of the Campanian-Maestrichtian seas. A residual seaway connecting the Bearpaw sea with that of West Greenland across the Canadian Arctic Archipelago and Baffin Bay continued to exist east of Mackenzie River until late Maestrichtian time. All of Arctic Canada became dry land in late Maestrichtian or early Paleocene time. End_of_Article - Last_Page 2488------------