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Title: Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor

Abstract

The Aleutian Ridge lies along nearly 2,000 km of the north Pacific's obliquely converging plate boundary with North America. Since middle Eocene time, convergent-margin basins have repeatedly formed here, typically as summit basins along the ridge crest, and as forecarc basins on the landward trench slope. Thick (1-4 km) sequences of terrigenous, hemipelagic, and biogenic debris have accumulated in these depressions, which are mostly intra-arc structures floored by arc-basement rocks. Summit and forearc basins formed as a consequence of plate-boundary coupling and the application of compressional and right-lateral shear stresses to the arc massif. Basins typically evolved along shear zones in response to transtensional processes, and as trailing-edge grabens behind rotating blocks of arc massif. In the late Cenozoic, high rates of trench sedimentation led to the growth of an accretionary complex that underthrust forearc basement. Wedging and improved plate coupling elevated and laterally shifted blocks of outer forearc rocks, creating much of the structural framework of the regionally extensive Aleutian Terrace forearc basin. Changes in plate-boundary conditions that affected the ridge's volcanic activity and regional elevation importantly influenced basinal sedimentation. Changes of greatest significant were a major shift in convergence direction and rate about 42 Ma (reduced volcanism), ridgemore » underthrusting by increasingly younger ocean crust in Oligocena and Miocene time (arc elevation), and the combination of more orthogonal underthrusting and the subduction of a dead spreading center 5-120 Ma (arc subsidence).« less

Authors:
; ; ;
Publication Date:
OSTI Identifier:
6083665
Alternate Identifier(s):
OSTI ID: 6083665
Report Number(s):
CONF-880301-
Resource Type:
Conference
Resource Relation:
Conference: Annual meeting of the American Association of Petroleum Geologists, Houston, TX, USA, 20 Mar 1988
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 03 NATURAL GAS; ALEUTIAN ISLANDS; PETROLEUM GEOLOGY; NATURAL GAS DEPOSITS; GEOLOGIC HISTORY; PETROLEUM DEPOSITS; SEDIMENTARY BASINS; PLATE TECTONICS; BASEMENT ROCK; CONTINENTAL MARGIN; EXPLORATION; SEDIMENTATION; STRATIGRAPHY; TERTIARY PERIOD; CENOZOIC ERA; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; GEOLOGY; ISLANDS; MINERAL RESOURCES; RESOURCES; TECTONICS 020200* -- Petroleum-- Reserves, Geology, & Exploration; 030200 -- Natural Gas-- Reserves, Geology, & Exploration

Citation Formats

Scholl, D.W., Ryan, H.F., Geist, E.L., and Vallier, T.L. Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor. United States: N. p., 1988. Web.
Scholl, D.W., Ryan, H.F., Geist, E.L., & Vallier, T.L. Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor. United States.
Scholl, D.W., Ryan, H.F., Geist, E.L., and Vallier, T.L. Fri . "Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor". United States. doi:.
@article{osti_6083665,
title = {Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor},
author = {Scholl, D.W. and Ryan, H.F. and Geist, E.L. and Vallier, T.L.},
abstractNote = {The Aleutian Ridge lies along nearly 2,000 km of the north Pacific's obliquely converging plate boundary with North America. Since middle Eocene time, convergent-margin basins have repeatedly formed here, typically as summit basins along the ridge crest, and as forecarc basins on the landward trench slope. Thick (1-4 km) sequences of terrigenous, hemipelagic, and biogenic debris have accumulated in these depressions, which are mostly intra-arc structures floored by arc-basement rocks. Summit and forearc basins formed as a consequence of plate-boundary coupling and the application of compressional and right-lateral shear stresses to the arc massif. Basins typically evolved along shear zones in response to transtensional processes, and as trailing-edge grabens behind rotating blocks of arc massif. In the late Cenozoic, high rates of trench sedimentation led to the growth of an accretionary complex that underthrust forearc basement. Wedging and improved plate coupling elevated and laterally shifted blocks of outer forearc rocks, creating much of the structural framework of the regionally extensive Aleutian Terrace forearc basin. Changes in plate-boundary conditions that affected the ridge's volcanic activity and regional elevation importantly influenced basinal sedimentation. Changes of greatest significant were a major shift in convergence direction and rate about 42 Ma (reduced volcanism), ridge underthrusting by increasingly younger ocean crust in Oligocena and Miocene time (arc elevation), and the combination of more orthogonal underthrusting and the subduction of a dead spreading center 5-120 Ma (arc subsidence).},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1988},
month = {Fri Jan 01 00:00:00 EST 1988}
}

Conference:
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