CGRG Bibliography of Canadian Geomorphology
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Author : Barrie, J.V.; and Conway, K.W.
Date : 1998
Title : Late Quaternary glaciation and post-glacial sea level response on the Northern Pacific Margin of Canada.
Publication : Abstract Volume, Joint meeting GAC, MAC, APGGQ, IAH, CGU, May 18-20, 1998, Quebec City
Issue :
Page(s) :
Abstract
An extensive glacier, at least 500 m in thickness, emanating from Clarence Strait of southeastern Alaska and the British Columbia mainland, joined by local ice from the northern Queen Charlotte Islands, moved through Dixon Entrance to the shelfbreak reaching maximum extent sometime after 21,000 14C yr B.P. South of Dixon Entrance, in northern Hecate Strait and the western Queen Charlotte Islands continental shelf, there is no evidence for late Wisconsin glaciation. Glacial retreat in Dixon Entrance began sometime after 15,000 14C yr B.P. and ice had completely left by 13,500 to 13,300 14C yr B.P. This deglaciation was followed by a rapid sea level fall and intrusion of warm Pacific water. A core obtained at the present day water depth of 37 m in northern Hecate Strait contains cold water foraminifera (Cassidula reniforme) in ice proximal laminated fine-grained sediments which date to 14,570 14C yr B.P.. Another core taken from a nearshore sand deposit in northeastern Hecate Strait at the junction with Dixon Entrance has been dated to between 12,710 and 12,880 14C yr B.P. in 77 m of water. The indication is that a rapid regression occurred on the continental shelf between approximately 14,600 and 12,500 14C yr B.P., contemporary with deglaciation, due almost entirely to rapid isostatic rebound. Sea level had reached a maximum lowering after 13,000 14C yr B.P. and remained low until approximately 10,400 14C yr B.P., after which a rapid transgression occurred. A contemporaneous shelf tilt existed across the northern Pacific margin of Canada ranging from 200 m of submergence at the fjord head near Kitimat on the British Columbia mainland to greater than 200 m of emergence on the western edge of the Queen Charlotte Islands at approximately 12,000 14C yr B.P., a result of a glacioisostatic forebulge. The collapse of the forebulge and eustatic sea level rise resulted in the transgression, submerging many present day coastal areas surrounding the Queen Charlotte Islands and Dixon Entrance by as much as 15 m.
Bibliography of Canadian Geomorphology