EDGE deep seismic reflection transect of the eastern Aleutian arc-trench layered lower crust reveals underplating and continental growth

Abstract

Research Article| May 01, 1991 EDGE deep seismic reflection transect of the eastern Aleutian arc-trench layered lower crust reveals underplating and continental growth J. Casey Moore; J. Casey Moore 1Department of Earth Sciences, University of California, Santa Cruz, California 95064 Search for other works by this author on: GSW Google Scholar John Diebold; John Diebold 2Lamont Doherty Geological Observatory, Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar M. A. Fisher; M. A. Fisher 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar J. Sample; J. Sample 4Department of Earth and Space Sciences, University of California, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar T. Brocher; T. Brocher 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar M. Talwani; M. Talwani 5Houston Area Research Center, 4802 Research Forest Drive, The Woodlands, Texas 77381 Search for other works by this author on: GSW Google Scholar John Ewing; John Ewing 5Houston Area Research Center, 4802 Research Forest Drive, The Woodlands, Texas 77381 Search for other works by this author on: GSW Google Scholar R. von Huene; R. von Huene 6Geomar, Wischhofstrasse 1-4,2300 Kiel 14, Germany Search for other works by this author on: GSW Google Scholar C. Rowe; C. Rowe 7Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701 Search for other works by this author on: GSW Google Scholar D. Stone; D. Stone 7Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701 Search for other works by this author on: GSW Google Scholar Chris Stevens; Chris Stevens 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Dale Sawyer Dale Sawyer 8Department of Geology, Rice University, Houston, Texas 77005 Search for other works by this author on: GSW Google Scholar Geology (1991) 19 (5): 420–424. https://doi.org/10.1130/0091-7613(1991)019<0420:EDSRTO>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. Casey Moore, John Diebold, M. A. Fisher, J. Sample, T. Brocher, M. Talwani, John Ewing, R. von Huene, C. Rowe, D. Stone, Chris Stevens, Dale Sawyer; EDGE deep seismic reflection transect of the eastern Aleutian arc-trench layered lower crust reveals underplating and continental growth. Geology 1991;; 19 (5): 420–424. doi: https://doi.org/10.1130/0091-7613(1991)019<0420:EDSRTO>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract An EDGE deep crustal seismic reflection transect of the eastern Aleutian arc-trench traces oceanic crust and Moho more than 200 km beneath the accretionary prism to depths of more than 30 km. These horizons project beneath a prominent sequence of layered reflectors that extends from about 9 to 35 km beneath the Mesozoic core of the prism. Earthquake hypocenters imply continuity of the downgoing lithosphere from the base of the layered reflectors to beneath and beyond the active Augustine volcano. Rapid lateral growth of the prism in Eocene-Oligocene time coincided with uplift of the Mesozoic core of the prism. During lateral growth, maintenance of critical taper requires thickening, either by internal deformation or underplating. Because exposed rocks show only modest postemplacement shortening, thickening most likely occurred by underplating, probably of the layered reflectors. The overall geometry of the layered reflectors is reminiscent of nappe structures, and their emplacement may represent crustal-scale duplexing associated with underplating. The EDGE reflection data and borehole results indicate that the shelf edge is marked by an active out-of-sequence thrust that separates the Paleogene and Neogene prisms. This thrust apparently developed in response to the prism's need to maintain critical taper and demonstrates that contrasts in lithology can result from mechanisms other than terrane emplacement. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.