Geochemical evidence for sediment accretion in the Costa Rica frontal prism

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doi: 10.1130/G25739A.1
Author(s): Cardace, Dawn; Morris, Julie D.
Author Affiliation(s): Primary:
NASA, Ames Research Center, Moffett Field, CA, United States
National Science Foundation, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 37(10), p.891-894. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2009224. 21 refs.; illus., incl. 1 table, sketch map
Summary: We report new geochemical data for marine sediments sampled in the frontal prism associated with the Costa Rica subduction zone during Leg 205 of the Ocean Drilling Program (ODP). We describe variation in sediment geochemistry with depth as the décollement zone, the interface between overriding and downgoing tectonic plates, is approached. This variation can be explained by three-component mixing of ash, lower plate sediments (LPS), and frontal prism or upper plate sediments (UPS). We detect in-mixing of LPS in localized sediment intervals, amounting to tens of vertical meters of LPS incorporation; no persuasive evidence of LPS transfer into the prism has been shown until this contribution. This inference of fine structure in the prism provides new insight into how tectonic kneading of sediments occurs in décollement zones.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; Accretion; Accretionary wedges; Central America; Costa Rica; Decollement; East Pacific; Geochemistry; Leg 205; Marine sediments; Nicoya Peninsula; North Pacific; Northeast Pacific; ODP Site 1254; ODP Site 1255; Ocean Drilling Program; Pacific Ocean; Sediments; Subduction zones
Coordinates: N093800 N094000 W0861000 W0861200
Record ID: 2009097992
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