Metamorphic facies indicated by vein minerals in basal beds of the Great Valley sequence, northern California

Edgar H. Bailey; David L. Jones

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USGS · 70161766

Metamorphic facies indicated by vein minerals in basal beds of the Great Valley sequence, northern California

Edgar H. Bailey·David L. Jones

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Abstract

A reexamination of reported blueschist mineral localities in the basal strata of the Great Valley sequence revealed only prehnite-pumpellyite facies minerals. Franciscan graywacke thrust below the Great Valley rocks contains lawsonite-quartz blueschist assemblages. At a common pressure of about 4 kb, the Franciscan blueschists formed at lower temperatures than the overlying Great Valley prehnite-bearing rocks, lending support to tectonic models that involve rapid subduction of the Franciscan rocks.

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Journal of Research of the U.S. Geological Survey Article

Source-reported bounding extent: 34.985003130171066° to 40.72228267283148° latitude; -122.71728515624999° to -118.66333007812499° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Edgar H. Bailey, David L. Jones. 1973. Metamorphic facies indicated by vein minerals in basal beds of the Great Valley sequence, northern California. https://pubs.usgs.gov/publication/70161766

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