Petrogenesis of alkaline basalts from Socorro Island, Mexico: trace element evidence for contamination of ocean island basalt in the shallow ocean crust

W. A. Bohrson, M. R. Reid

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Postcaldera mafic volcanism on Socorro Island, Mexico, an island located in the eastern Pacific Ocean on a segment of a mid-ocean ridge spreading center abandoned at ~3.5 Ma, dominantly comprises alkalic basalt, hawaiite, and mugearite with subordinate mildly alkalic-transitional basalt. Most major element data are consistent with differentiation of alkalic basalt to hawaiite and mugearite by up to 50% fractionation of plagioclase + clinopyroxene + olivine ± Fe-Ti oxides. Sr and Nd isotopic ratios exhibit relatively narrow ranges. Despite this, a subset of the alkalic basalts has negative Ce anomalies and abundances of P2O5, Ba, Y, and some REEs in excess of those predicted by fractional crystallization models; these chemical features require open-system processes. The observed heterogeneities are perhaps best explained by assimilation of ocean crustal components by basalt in a shallow magma reservoir. -from Authors

Original languageEnglish (US)
Pages (from-to)24,555-24,576
JournalJournal of Geophysical Research
Volume100
Issue numberB12
StatePublished - Jan 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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