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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 64 (1980)

Issue: 3. (March)

First Page: 446

Last Page: 446

Title: Twentieth-Century History of Gulf of Alaska Coastline, Cape Suckling to Cape Spencer: ABSTRACT

Author(s): Bruce F. Molnia

Article Type: Meeting abstract


The 500 km of Gulf of Alaska coastline between Cape Suckling and Cape Spencer contains several segments that may be the most actively changing and dynamic on the earth's surface. Included in the changes during the twentieth century are the filling of two bays, the formation of a third bay, and the erosion and retreat of more than 250 km of coastline, some by more than 2 km.

Baseline information for this study consists of 1893-1920 maps prepared by the U.S.-Canadian Boundary Survey, pre-1920 U.S. Geological Survey investigations, later maps from many sources, and photographs made since 1895. Field observations to refine and confirm map interpretations were conducted between 1975 and 1979.

Tsivat and Kaliakh Bays, both mapped on 1913 USGS topographic maps, filled in with glacially derived sediment before 1940. Icy Bay, a 40-km-long fiord, has formed since 1906 following the retreat of Guyot glacier. The coastline east of Icy Bay has retreated 1.3 km since 1940 and probably twice that amount since 1906.

This stretch of coast also includes Lituya Bay, the site of at least two earthquake-generated giant waves in this century alone, and Malaspina glacier, where 66 sq km of new coastal land formed between 1895 and 1941. In the past four decades the new Malaspina coastline has undergone erosion and retreat.

Many other smaller changes have occurred, most of which can be well documented. Despite the remoteness of the study area, it may prove to be one of the best observation areas for studying the dynamics of actively changing coastlines.

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Copyright 1997 American Association of Petroleum Geologists