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Sediment delivery and depositional processes along the eastern Aleutian Trench

Maxwell Richard Dobson and Dennis O'Leary
Sediment delivery and depositional processes along the eastern Aleutian Trench
Journal of the Geological Society of London (May 2019) Pre-Issue Publication

Abstract

The Aleutian trench contains vast volumes of clastic sediment sourced mainly from the glacial erosion of Alaska and controlled by allocyclic influences. GLORIA and multi-channel seismic surveys conducted by the USGS revealed details of both the geometry and distribution of the trench sediments and their associated supply systems. Milankovitch-induced climatic cycles cause the episodic release of sediment transported as both unconfined and confined turbid flows, the latter routed along submarine channels that cross the abyssal plain of the Gulf of Alaska and discharge into the trench. Small volumes of sediment enter the trench directly from glacier snouts at the transform trough-end of the trench and from the Chugach Mountains in the north. A major channel system extends along the trench axis which acts as a conduit for turbid sediment flows. The channel also reworks and redistributes material supplied from the accretionary prism and the oceanic plate. Subduction of seamount chains coupled with the westward-increasing obliquity of plate collision and accretionary prism-sourced slump, that may be seismically triggered, segment the trench environment dividing the axial channel system into discrete flow patterns. This effect of compartmentalization creates petrographically distinct segments of fill partly due to the primary source landscape of accreted terranes formed of ancient island arcs. This serves to emphasize the cyclic nature of earth processes.


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: Pre-Issue Publication
Title: Sediment delivery and depositional processes along the eastern Aleutian Trench
Affiliation: Ravenscroft, Waun Fawr, Aberystwyth, United Kingdom
Published: 20190528
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 54
Accession Number: 2019-081155
Categories: Applied geophysicsSedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., geol. sketch maps
N53°00'00" - N59°00'00", W162°00'00" - W144°00'00"
Secondary Affiliation: U. S. Geological Survey, USA, United States
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 2019
Program Name: USGSOPNon-USGS publications with USGS authors
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