A 13 ± 3 ka age determination of a tholeiite, Pinacate volcanic field, Mexico, and improved methods for 40Ar/39Ar dating of young basaltic rocks

Brent D. Turrin, James T. Gutmann, Carl C. Swisher

Research output: Contribution to journalArticle

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Abstract

Among the youngest lava flows of the Pinacate volcanic field, Sonora, Mexico, is a large outpouring of tholeiite, the Ives flow. This tube-fed pahoehoe flow contrasts sharply with other Pinacate lavas in its great volume, alkali-poor composition and morphologic features, which include novel small structures named "spatter tubes." Despite its K-poor character, young age, and the presence of excess 40Ar, we determined a 40Ar/39Ar age on samples of this flow at 13 ± 3 ka. Such an age determination is made possible via careful monitoring of the mass discrimination of the mass spectrometer and by stacking results from multiple incremental-heating experiments into a single, composite isochron. This age is among the youngest ever to be determined with such precision by the 40Ar/39Ar method on a K-poor tholeiite.

Original languageEnglish (US)
Pages (from-to)848-856
Number of pages9
JournalJournal of Volcanology and Geothermal Research
Volume177
Issue number4
DOIs
Publication statusPublished - Nov 20 2008

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All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Keywords

  • Ar/Ar dating
  • Pinacate volcanic field
  • mass spectrometry
  • spatter tubes

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