The Alaskan Shelf

Abstract

This volume represents the work achieved over a number of years during which many students and assistants provided their talents in the laboratory as well as onboard ship. Special thanks are extended to Miss Shalini Sharma and Mr. David Burbank who helped generously during collection and analysis of samples, data processing, and drafting.I am especially grateful to Dr. Joe S. Creager for providing sediment samples from some regions of the Chukchi and Bering seas and for his generous cooperation and assistance extended to me during my stay at the University of Washington.The computer analysis was performed under the supervision of Mr. Ivan Frohne, Dr. Dan Hawkins, and Dr. James Kelley, and their expert assistance is much appreciated.The book was reviewed by Dr. Tom Mowatt, Prof. AI Belon, Dr. D. M. Hopkins, and Prof. G. M. Friedman. These reviews deserve many thanks for their cooperation and quality efforts.Finally, I wish to thank my wife, Norma, for typing the original draft and for her patience.

Carbonates within a Pleistocene glaciomarine succession, Yakataga Formation, Middleton Island, Alaska

“…The terrigenous sediment was transported onto most of the shelf by suspension during interglacials and by melting of glacial ice and icebergs on the shelf itself. Higher latitude shelves with extensive seasonal ice but not glacial ice today are simply veneered with mud with few dropstones (Sharma, 1979), quite unlike the Yakataga Formation.…”

“…Tertiary and Pleistocene stratified rocks form the sea floor on Tarr bank, on the Middleton Island Shelf. Tarr Bank is covered with coarse bioclastic material, (Sharma, 1979; Powell & Molnia, 1989) but little information is available. The coarse material either is relict from the last glaciation or, in the case of the carbonate, is being produced in place because coarse material is not transported to offshore banks today (Sharma, 1979; Powell & Molnia, 1989).…”

“…Tarr Bank is covered with coarse bioclastic material, (Sharma, 1979; Powell & Molnia, 1989) but little information is available. The coarse material either is relict from the last glaciation or, in the case of the carbonate, is being produced in place because coarse material is not transported to offshore banks today (Sharma, 1979; Powell & Molnia, 1989). If fine material is deposited from suspension, it is resuspended by wave action and winnowed from the bank leaving the outer banks as regions of siliciclastic non‐deposition.…”

“…A much better, but poorly understood, sea floor analogue of coarse, epifanal mollusc‐dominated sediments seems to be present today atop Middleton Bank, probably because continuous wave winnowing keeps fine siliciclastic muds from accumulating (Sharma, 1979; Powell & Molnia, 1989). A similar situation is present on the outer parts of Kodiak Bank some 300 km to the west of Middleton Island Bank (Cuffey & Turner, 1987) wherein the shallow bank top is flat‐topped, less than 100 m deep, is covered with sand and boulders, supports a calcareous, bryozoan‐dominated biota and is swept clear of fine‐grained sediment by waves and currents.…”