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, Mary Reid

Research output: Contribution to journalArticle

37 Citations (Scopus)

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)
JournalJournal of Geophysical Research E: Planets
Volume100
Issue numberB12
StatePublished - 1995
Externally publishedYes

Fingerprint

petrogenesis
basalt
ocean island basalt
Mexico
Trace Elements
trace elements
crusts
oceans
contamination
Contamination
trace element
crust
ocean
phosphorus pentoxide
plagioclase
volcanic activity
mid-ocean ridges
Pacific Ocean
Open systems
spreading center

ASJC Scopus subject areas

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

Cite this

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title = "Petrogenesis of alkaline basalts from Socorro Island, Mexico: trace element evidence for contamination of ocean island basalt in the shallow ocean crust",
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",
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year = "1995",
language = "English (US)",
volume = "100",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "B12",

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TY - JOUR

T1 - Petrogenesis of alkaline basalts from Socorro Island, Mexico

T2 - trace element evidence for contamination of ocean island basalt in the shallow ocean crust

AU - Bohrson, W. A.

AU - Reid, Mary

PY - 1995

Y1 - 1995

N2 - 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

AB - 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

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