Hot, shallow mantle melting under the Cascades volcanic arc

Linda T. Elkins Tanton, Timothy L. Grove, Julie Donnelly-Nolan

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

Melting occurs at progressively greater depths and higher temperatures from west to east across the Cascades volcanic arc in northern California, as demonstrated by compositional variations observed in high-alumina olivine tholeiites. The lavas studied erupted from seven vents defining a 75-km-long, east-west transect across the arc, from near Mount Shasta to east of Medicine Lake volcano. The increase in melting depth across the arc parallels modeled isotherms in the mantle wedge and does not parallel the inferred dip of the slab. The depth of mantle melting at which the high-alumina olivine tholeiites were created is ∼36 km at the western end of the transect and 66 km at the eastern end. The very high temperatures of dry melting so close to the crust indicate a transitory condition of the mantle.

Original languageEnglish (US)
Pages (from-to)631-634
Number of pages4
JournalGeology
Volume29
Issue number7
DOIs
StatePublished - Jul 1 2001
Externally publishedYes

Keywords

  • Cascade Range
  • Mantle
  • Melting
  • Petrology
  • Subduction zones
  • Tholeiite

ASJC Scopus subject areas

  • Geology

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