Plio-Quaternary Outer Forearc Deformation and Mass Balance of the Southern Costa Rica Convergent Margin

Kristin D. Morell, Donald M. Fisher, Nathan Bangs

Research output: Contribution to journalArticle

Abstract

Identifying the processes that control the rates, magnitudes, and longevity of outer forearc deformation is fundamental to our understanding of how mass is distributed within subduction zone systems. The margin of southern Costa Rica has been the target of numerous onland field studies, geophysical surveys, and the Costa Rica Seismogenesis Project (CRISP) drilling expedition. Despite these extensive data sets, the relative roles that subduction erosion, shortening, and seamount subduction play in shaping the behavior and evolution of the outer forearc remain debated. Here we analyze new and existing geomorphic, geologic, stratigraphic, and geochronologic data sets across the entire forearc-arc-backarc system near the Costa Rica Seismogenesis Project transect to test several conceptual models for outer forearc deformation in southern Costa Rica. The results from the compilation agree with a model where recent arcward retreat of the trench (movement of the trench in the direction of the arc) occurs due to underthrusting of the outer forearc beneath the inner forearc, and outer forearc deformation occurs primarily by transient rapid vertical tectonism due to the subduction of bathymetric relief. These results lead to a new conceptual model for Plio-Quaternary outer forearc deformation in southern Costa Rica that does not require large amounts of net mass loss within the upper plate.

Original languageEnglish (US)
Pages (from-to)9795-9815
Number of pages21
JournalJournal of Geophysical Research: Solid Earth
Volume124
Issue number9
DOIs
StatePublished - Sep 1 2019

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Costa Rica
convergent margin
mass balance
margins
subduction
trench
arcs
geophysical survey
expeditions
seamount
seamounts
subduction zone
Process control
Erosion
Drilling
relief
drilling
transect
erosion
project

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

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Plio-Quaternary Outer Forearc Deformation and Mass Balance of the Southern Costa Rica Convergent Margin. / Morell, Kristin D.; Fisher, Donald M.; Bangs, Nathan.

In: Journal of Geophysical Research: Solid Earth, Vol. 124, No. 9, 01.09.2019, p. 9795-9815.

Research output: Contribution to journalArticle

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