Seismic evidence for lithospheric modification beneath the Mojave Neovolcanic Province, Southern California

Chelsea M. Allison, Ryan C. Porter, Matthew J. Fouch, Steven Semken

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

The Mojave Neovolcanic Province (MNVP), located in the Mojave block of southern California, comprises late Miocene to Quaternary small-volume basaltic centers. Geochemistry indicates an asthenospheric source for the MNVP beginning in the late Miocene, but no physical evidence of missing mantle lithosphere has been presented. We utilize receiver functions and ambient noise tomography to image the lithosphere beneath the Mojave block. Regionally, we find thin crust that thickens distal to sites of MNVP volcanism. Shear wave velocities between 40 and 75 km depth are consistent with the presence of mantle lithosphere in the southern Mojave block and very thin or missing mantle lithosphere to the north. With one exception, MNVP volcanoes lie along this sharp boundary. Our observations, together with the established geologic history and geochemistry of the MNVP, can be explained by small-scale edge-driven convection producing ongoing lithospheric removal within the Mojave block. Our results provide another example of lithospheric instability that occurs in response to rapid changes in mantle dynamics induced by major changes in tectonic plate geometry. Key Points Crust is thin and partial melt may exist beneath portions of Mojave block Strong lateral differences in lithosphere control recent (< 5 Ma) volcanism Destruction of Mojave lithosphere continues near Amboy Crater

Original languageEnglish (US)
Pages (from-to)5119-5124
Number of pages6
JournalGeophysical Research Letters
Volume40
Issue number19
DOIs
StatePublished - Oct 16 2013

Keywords

  • Cima volcanic field
  • Mojave block
  • Western North America
  • ambient noise tomography
  • lithospheric destabilization
  • receiver functions

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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