Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Pb and Os isotopic constraints on the composition and rheology of the lower crust

Yemane Asmerom and Richard J. Walker
Pb and Os isotopic constraints on the composition and rheology of the lower crust
Geology (Boulder) (April 1998) 26 (4): 359-362

Abstract

We report inversely correlated Os and Pb isotopic data from mantle-derived continental rift basalts from Death Valley, California. The data project toward a crustal end member that is extremely radiogenic with respect to Os and nonradiogenic with respect to Pb, and a mantle end member that is unradiogenic with respect to Os and moderately radiogenic with respect to Pb. The data favor ancient mafic lower crust as the source of the radiogenic Os. A mafic lower crust composition for the Basin and Range leads to rheological coupling between strong lower crust and lithospheric mantle. This may explain the flat Moho topography seen across extended and stable crustal blocks, necessitating upper crustal and lower crustal strain decoupling, leaving the more fluid middle crust across which upper crustal mass compensation must have occurred.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 26
Serial Issue: 4
Title: Pb and Os isotopic constraints on the composition and rheology of the lower crust
Affiliation: University of New Mexico, Radiogenic Isotope Laboratory, Albuquerque, NM, United States
Pages: 359-362
Published: 199804
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 39
Accession Number: 1998-027840
Categories: Isotope geochemistryIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
N29°00'00" - N43°30'00", W122°00'00" - W102°30'00"
N35°45'00" - N37°30'00", W118°45'00" - W115°40'00"
Secondary Affiliation: University of Maryland, College Park, MD, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 199811
Close Modal

or Create an Account

Close Modal
Close Modal