Rates of mantle cooling and exhumation during rifting constrained by REE-in-pyroxene speedometry

A. Smye, S. Seman, M. Hudak, K. Crispin

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Ocean basins are formed when continents are broken apart. Adiabatic melt generation that is driven by rifting of continental lithosphere is strongly dependent on the rate of extension. Slow extension results in conductive heat loss from the upwelling mantle, whereas cooling is limited during fast extension and can result in the geotherm intersecting the peridotite solidus. However, there are few direct constraints on the rates of mantle upwelling during extension of continental lithosphere. Here we use diffusion modeling of subsolidus REE re-equilibration between orthopyroxene and clinopyroxene to show that the Lanzo peridotite massif—lithospheric mantle exhumed during opening of the Ligurian Tethys—cooled at rates between 5 and 25°C/Myr across the spinel-to-plagioclase peridotite facies transition. We show that these rates are sufficiently slow to suppress significant adiabatic melt generation, providing an explanation for the magma-poor nature of the Alpine Tethys margin.

Original languageEnglish (US)
Pages (from-to)2510-2525
Number of pages16
JournalGeochemistry, Geophysics, Geosystems
Volume18
Issue number7
DOIs
StatePublished - Jan 1 2017

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

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