The role of water in connecting past and future episodes of subduction

Suzan van der Lee, Klaus Regenauer-Lieb, Dave A. Yuen

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

We investigate a weak, but persistent low S-velocity anomaly in the upper mantle beneath the US East Coast. This anomaly sits above the high-velocity lower-mantle S-velocity structure generally interpreted as relatively cool, subducted Farallon lithosphere. We argue that the most likely explanation for the lowered S-velocities is elevated water content, with hydrogen incorporated in defects and oxygen at regular lattice sites in the crystal structure of major mantle minerals olivine, wadsleyite, and ringwoodite. The subducted Farallon lithosphere is a potential source for this water while the lithosphere at the Atlantic North American margin is a likely recipient of the water. This water may be the vital element needed to allow the margin lithosphere to break and initiate subduction of the Atlantic lithosphere. In a broader geodynamic context we propose that a deep water cycle may be responsible for the longevity of plate tectonics in general and the Wilson Cycle in particular.

Original languageEnglish (US)
Pages (from-to)15-27
Number of pages13
JournalEarth and Planetary Science Letters
Volume273
Issue number1-2
DOIs
StatePublished - Aug 30 2008

Bibliographical note

Funding Information:
We are grateful to Steve Grand for making his 2002 S -velocity model available, to S. Mark Wang for help with visualizing NA04 in three dimensions, and to Steven Jacobsen, Scott King, Federica Marone, and Anne Trehu for thoughtful reviews. This work was funded by the NSF-Earthscope program under grant EAR-0346200 and Northwestern University's Howland Fund (SL), ITR and Math-Geo grants of NSF (DAY), and CSIRO (KRL). KRL wishes to thank the Western Australian Government for the Premier's Fellowship support.

Keywords

  • Atlantic Ocean
  • North America
  • S velocity
  • Wilson cycle
  • dehydration
  • hydrous minerals
  • seismic tomography
  • subduction
  • subduction initiation
  • transition zone

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