Flow of mantle fluids through the ductile lower crust: Helium isotope trends

B. Mack Kennedy, Matthijs Van Soest

Research output: Contribution to journalArticle

154 Scopus citations

Abstract

Heat and mass are injected into the shallow crust when mantle fluids are able to flow through the ductile lower crust. Minimum 3He/ 4He ratios in surface fluids from the northern Basin and Range Province, western North America, increase systematically from low crustal values in the east to high mantle values in the west, a regional trend that correlates with the rates of active crustal deformation. The highest ratios occur where the extension and shear strain rates are greatest. The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local, high 3He/4He anomalies indicating hidden magmatic activity and/or deep fluid production with locally enhanced permeability, identifying zones with high resource potential, particularly for geothermal energy development.

Original languageEnglish (US)
Pages (from-to)1433-1436
Number of pages4
JournalScience
Volume318
Issue number5855
DOIs
StatePublished - Nov 30 2007

ASJC Scopus subject areas

  • General

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