Please use this identifier to cite or link to this item:
logo share SHARE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE

A dense, intersecting array of normal faults on the outer shelf off Southern Costa Rica, associated with subducting Quepos ridge

AuthorsSilver, Eli A.; Kluesner, Jared W.; Gibson, James; Bangs, Nathan L.; McIntosh, Kirk D.; Von Huene, Roland; Ranero, César R. CSIC ORCID
Issue Date3-Dec-2012
PublisherAmerican Geophysical Union
CitationAGU Fall Meeting: T43E-2725 (2012)
AbstractUse of narrow, fixed swath multibeam data with high sounding densities has allowed order of magnitude improvement in image resolution with EM122 multibeam and backscatter data, as part of a 3D seismic study west of the Osa Peninsula. On the outer shelf, along the projection of the subducting Quepos Ridge, we mapped a dense array of faults cutting an arcuate, well-layered set of outcropping beds in the backscatter imagery (mosaicked at 2 m), with roughly N-S and E-W trends. The N-S trends dominate, and show inconsistent offsets, implying that the faults are normal and not strike-slip. The faults also show normal displacement in the 3D seismic data, consistent with the surface interpretation. The outcropping beds (of late Pleistocene age, based on Expedition 334 drilling), may have been truncated during the late Pleistocene low sea-level stand. The outermost shelf (edged by arcuate bathymetric contours) does not show these folded beds, as it was below wave base and buried by a thin sediment layer. However, narrow lines of small pockmarks and mounds follow the fault trends exactly, indicating that fluid flow through the faults is expressed at the surface, including a gas plume that extends to the sea-surface. The almost unprecedented increase in resolution of the EM122 data allows us to infer that the N-S, E-W grid of faults overlying the NE-trending Quepos Ridge projection (and NE directed subduction) formed by extensional arching above the ridge, not by collisional slip lines at a rigid indenter (as proposed earlier based on sandbox models). The extensional fault pattern also facilitates fluid and gas flow through the sedimentary section. © 2014 American Geophysical Union. All Rights Reserved
DescriptionAGU Fall Meeting 3–7 December 2012, San Francisco, California
Publisher version (URL)
Appears in Collections:(ICM) Comunicaciones congresos

Show full item record
Review this work

Page view(s)

checked on May 25, 2022

Google ScholarTM


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.