Chemical and Isotopic Cycling in Subduction Zones

Research output: Chapter in Book/Report/Conference proceedingChapter

48 Citations (Scopus)

Abstract

Subduction zones are avenues for the delivery of crustal, atmospheric, and oceanic (including organic) components to the mantle and understanding of subduction zone chemical and isotopic cycling is central to many models of crust-mantle-atmosphere evolution. During subduction, diagenetic and metamorphic reactions and related geochemical effects can profoundly influence the element inventory and isotopic composition of subducting slabs to depths beneath volcanic arcs and as they enter the deeper mantle. Physical juxtaposition of chemically disparate rocks and the generation and mobility of various fluids lead to myriad metasomatic effects in subduction zones. Larger scale manifestations of such processes include the mass transfer that leads to arc magmatism and convergent margin volatile cycling. Subduction zone metasomatism is initiated at very shallow levels, as oceanic slabs entering trenches bend and are infiltrated by seawater, and as sedimentary sections experience physical compaction, fluid expulsion, and diagenetic alteration. Studies of forearc fluid geochemistry track this shallow-level metasomatic alteration, and high- and ultrahigh-pressure metamorphic rock suites provide records of fluid generation and flow, and related metasomatism, to depths exceeding those beneath volcanic fronts. Subduction zone processes act as a geochemical filter, altering the compositions of deeply subducting rocks and generating outputs such as arc magmas (and associated volcanic gases) and chemically and isotopically modified rocks. The latter enter the deeper mantle and influence its long-term geochemical evolution.

Original languageEnglish
Title of host publicationTreatise on Geochemistry
Subtitle of host publicationSecond Edition
PublisherElsevier Inc.
Pages703-747
Number of pages45
Volume4
ISBN (Print)9780080983004
DOIs
Publication statusPublished - Nov 1 2013
Externally publishedYes

Keywords

  • Arc volcanism
  • Chemical cycling
  • Chemical geodynamics
  • Eclogite
  • Metamorphism
  • Subduction zone

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)
  • Chemistry(all)

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  • Cite this

    Bebout, G. E. (2013). Chemical and Isotopic Cycling in Subduction Zones. In Treatise on Geochemistry: Second Edition (Vol. 4, pp. 703-747). Elsevier Inc.. https://doi.org/10.1016/B978-0-08-095975-7.00322-3