Pulsed subduction accretion and tectonic erosion reconstructed since 2.5 Ma from the tephra record offshore Costa Rica

View/ Open
Date
2005-09-27Author
Clift, Peter D.
Concept link
Chan, Lui-Heung
Concept link
Blusztajn, Jerzy S.
Concept link
Layne, Graham D.
Concept link
Kastner, Miriam
Concept link
Kelly, Robyn K.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/446As published
https://doi.org/10.1029/2005GC000963DOI
10.1029/2005GC000963Keyword
Costa Rica; Subduction; Geochemistry; TephraAbstract
Tephra layers recovered by Ocean Drilling Program from the forearc and trench regions offshore the Nicoya Peninsula of Costa Rica allow the temporal evolution of the volcanic arc to be reconstructed since 2.5 Ma. Major and trace element analyses by microprobe methods reveal a dominant tholeiitic character and a provenance in the Costa Rican area. The tephra show long-term coherent variability in geochemistry. One tephra dated at 1.45 Ma shows minimum values in ɛ Nd and maximum Li/Y consistent with very high degrees of sediment recycling at this time. However, overall Li/Y and δ7Li increase with SiO2 content, suggesting addition of heavy Li through forearc tectonic erosion and crustal assimilation. Peak values in δ7Li starting at 1.45 Ma and lasting ∼0.5 m.y. indicate enhanced tectonic erosion of the forearc possibly caused by subduction of a seamount at 1.45 Ma. The tephra record indicates significant temporal variability in terms of sediment subduction, reconciling the geologic evidence for long-term tectonic erosion and geochemical evidence for recent sediment accretion in the modern Central American arc.
Description
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of
American Geophysical Union for personal use, not for redistribution. The definitive version was published
in Geochemistry Geophysics Geosystems 6 (2005): Q09016, doi:10.1029/2005GC000963.
Collections
Suggested Citation
Geochemistry Geophysics Geosystems 6 (2005): Q09016Related items
Showing items related by title, author, creator and subject.
-
Seismic evidence for fluids in fault zones on top of the subducting Cocos Plate beneath Costa Rica
Van Avendonk, Harm J. A.; Holbrook, W. Steven; Lizarralde, Daniel; Mora, Mauricio M.; Harder, Steven H.; Bullock, Andrew D.; Alvarado, Guillermo E.; Ramirez, Carlos J. (John Wiley & Sons, 2010-03-09)In the 2005 TICOCAVA explosion seismology study in Costa Rica we observed crustal turning waves with a dominant frequency of ~10 Hz on a linear array of short-period seismometers from the Pacific Ocean to the Caribbean ... -
Structure and serpentinization of the subducting Cocos plate offshore Nicaragua and Costa Rica
Van Avendonk, Harm J. A.; Holbrook, W. Steven; Lizarralde, Daniel; Denyer, P. (American Geophysical Union, 2011-06-22)The Cocos plate experiences extensional faulting as it bends into the Middle American Trench (MAT) west of Nicaragua, which may lead to hydration of the subducting mantle. To estimate the along strike variations of volatile ... -
Inventory of push cores taken on Alvin dives on RV/Atlantis cruise AT37-13 and AT42-03 at methane seeps off the Pacific coast of Costa Rica (Costa Rica Seeps project)
Orphan, Victoria J.; Cordes, Erik E. (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-01-21)This dataset is an inventory of push corer samples collected by HOV/Alvin on the RV/Atlantis cruises AT/37-13 and AT42-03 to the Costa Rica Margin (Mound 12, Quepos landslide, Jaco Scar) during May/June 2017 and Oct./Nov ...