Crustal structure beneath exposed accreted terranes of Southern Alaska

Geophysical Journal International
By: , and 

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Abstract

The crustal structure beneath the exposed terranes of southern Alaska has been explored using coincident seismic refraction and reflection profiling. A wide-angle reflector at 8-9 km depth, at the base of an inferred low-velocity zone, underlies the Peninsular and Chugach terranes, appears to truncate their boundary, and may represent a horizontal decollement beneath the terranes. The crust beneath the Chugach terrane is characterized by a series of north-dipping paired layers having low and high velocities that may represent subducted slices of oceanic crust and mantle. This layered series may continue northward under the Peninsular terrane. Earthquake locations in the Wrangell Benioff zone indicate that at least the upper two low-high velocity layer pairs are tectonically inactive and that they appear to have been accreted to the base of the continental crust. The refraction data suggest that the Contact fault between two similar terranes, the Chugach and Prince William terranes, is a deeply penetrating feature that separates lower crust (deeper than 10 km) with paired dipping reflectors, from crust without such reflectors.

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Publication type Article
Publication Subtype Journal Article
Title Crustal structure beneath exposed accreted terranes of Southern Alaska
Series title Geophysical Journal International
DOI 10.1111/j.1365-246X.1987.tb04390.x
Volume 89
Issue 1
Year Published 1987
Language English
Publisher Oxford Academic
Contributing office(s) Earthquake Science Center
Description 6 p.
First page 73
Last page 78
Country United States
State Alaska
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