A recent phase of accretion along the southern Costa Rican subduction zone

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doi: 10.1016/j.epsl.2016.03.008
Author(s): Bangs, Nathan L.; McIntosh, Kirk D.; Silver, Eli A.; Kluesner, Jared W.; Ranero, César R.
Author Affiliation(s): Primary:
University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
University of California at Santa Cruz, United States
U. S. Geological Survey, United States
Barcelona Center for Subsurface Imaging, Spain
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.443, p.204-215. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 39 refs.; illus., incl. sects., sketch maps
Summary: In 2011 we acquired a 3D seismic reflection volume across the Costa Rica margin NW of the Osa Peninsula to investigate the complex structure and the development of the seismogenic zone within the Costa Rican subduction zone in the vicinity of recent International Ocean Drilling Program (IODP) drilling. In contrast to previous interpretations, these newly acquired seismic images show that the margin wedge is composed of a layered fabric that is consistent with clastic sediments, similar to materials recovered from IODP drilling, that have been thrust and thickened into thrust-bounded folded sequences. These structures are consistent with a balanced sequence that has been frontally accreted in the context of an accretionary model. We interpret these sequences as sediment originally deposited on the subducting crust in a trench basin created by the southward migration of the Cocos-Nazca-Caribbean triple junction, and accreted during recent margin subduction that also accelerated with passage of the triple junction. The margin is composed of relatively rapidly accreted sediment that was added to the margin during a phase of accretion within the last ∼5 Ma that was probably preceded throughout the Neogene by periods of non-accretion or erosion. Abstract Copyright (2016) Elsevier, B.V.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; 20 Geophysics, Applied; Accretion; Accretionary wedges; Central America; Clastic sediments; Costa Rica; Costa Rican subduction zone; Crustal shortening; Deformation; Erosion; Fabric; Faults; Folds; Geophysical methods; Geophysical surveys; Imagery; Integrated Ocean Drilling Program; Layered materials; Normal faults; Osa Peninsula; Plate tectonics; Sediments; Seismic methods; Subduction; Subduction zones; Surveys; Three-dimensional models; Thrust faults; Triple junctions; Unconformities
Coordinates: N080000 N093000 W0833000 W0843000
Record ID: 2016056399
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands