Paleozoic Basins and Shelf Deposits of the Central Brooks Range, Possible Analogs to Basins Under the Arctic Coastal Plain, Northern Alaska

J. S. Kelley, W. P. Brosge

Our palinspastic restoration of Upper Devonian to Lower Cretaceous rocks in the central Brooks Range clarifies regional depositional patterns some of which have implications for little-explored rocks under the Arctic coastal plain. Restorations show Late Devonian to Early Mississippian(?) basins that are not present in the northeastern Brooks Range. Early Mississippian to Jurassic shelf deposits conformably overlie these basins in the central Brooks Range whereas they unconformably overlie basement in the northeastern Brooks Range. In gross aspect, these shelf deposits change westward from deposits composed of carbonate and terrigenous clastic debris typical of the northeastern Brooks Range to slope and basin deposits composed of hemipelagic and pelagic debris typical of he western Brooks Range. Shallow water shelly deposits of Early Cretaceous age that overlie the basins in the central Brooks Range may be low stand deposits associated with an unconformity exposed in the northeastern Brooks Range and widely recognized under the Arctic coastal plain.

Relations between basins and overlying shelf deposits exposed in the north-central Brooks Range may be analogs for relations under the North Slope foreland basin between Paleozoic deposits in the Umiat, Ikpikpuk, and Meade basins and the overlying shelf deposits. In the central Brooks Range during Early Mississippian to Early Cretaceous time, shelf areas above the Late Devonian to Early Mississippian basins subsided more than adjacent areas where shelf deposits lie on basement thereby producing local shelf basins where potential source rocks were deposited. Similar beds may be present in Lower Mississippian to Lower Cretaceous rocks that overlie Paleozoic basins beneath the North Slope foreland basin.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995