Seismic evidence for widespread serpentinized forearc upper mantle along the Cascadia margin

Research Article| March 01, 2003 Seismic evidence for widespread serpentinized forearc upper mantle along the Cascadia margin Thomas M. Brocher; Thomas M. Brocher 1U.S. Geological Survey, MS 977, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Tom Parsons; Tom Parsons 2U.S. Geological Survey, MS 999, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Anne M. Tréhu; Anne M. Tréhu 3College of Oceanography, Oceanography Administration Building 104, Oregon State University, Corvallis, Oregon 97331, USA Search for other works by this author on: GSW Google Scholar Catherine M. Snelson; Catherine M. Snelson 4Department of Geoscience, University of Nevada, Las Vegas, Nevada 89154-4010, USA Search for other works by this author on: GSW Google Scholar Michael A. Fisher Michael A. Fisher 5U.S. Geological Survey, MS 999, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Thomas M. Brocher 1U.S. Geological Survey, MS 977, Menlo Park, California 94025, USA Tom Parsons 2U.S. Geological Survey, MS 999, Menlo Park, California 94025, USA Anne M. Tréhu 3College of Oceanography, Oceanography Administration Building 104, Oregon State University, Corvallis, Oregon 97331, USA Catherine M. Snelson 4Department of Geoscience, University of Nevada, Las Vegas, Nevada 89154-4010, USA Michael A. Fisher 5U.S. Geological Survey, MS 999, Menlo Park, California 94025, USA Publisher: Geological Society of America Received: 18 Jun 2002 Revision Received: 04 Nov 2002 Accepted: 11 Nov 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (3): 267–270. https://doi.org/10.1130/0091-7613(2003)031<0267:SEFWSF>2.0.CO;2 Article history Received: 18 Jun 2002 Revision Received: 04 Nov 2002 Accepted: 11 Nov 2002 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 Thomas M. Brocher, Tom Parsons, Anne M. Tréhu, Catherine M. Snelson, Michael A. Fisher; Seismic evidence for widespread serpentinized forearc upper mantle along the Cascadia margin. Geology 2003;; 31 (3): 267–270. doi: https://doi.org/10.1130/0091-7613(2003)031<0267:SEFWSF>2.0.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 Petrologic models suggest that dehydration and metamorphism of subducting slabs release water that serpentinizes the overlying forearc mantle. To test these models, we use the results of controlled-source seismic surveys and earthquake tomography to map the upper mantle along the Cascadia margin forearc. We find anomalously low upper-mantle velocities and/or weak wide-angle reflections from the top of the upper mantle in a narrow region along the margin, compatible with recent teleseismic studies and indicative of a serpentinized upper mantle. The existence of a hydrated forearc upper-mantle wedge in Cascadia has important geological and geophysical implications. For example, shearing within the upper mantle, inferred from seismic reflectivity and consistent with its serpentinite rheology, may occur during aseismic slow slip events on the megathrust. In addition, progressive dehydration of the hydrated mantle wedge south of the Mendocino triple junction may enhance the effects of a slab gap during the evolution of the California margin. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.