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GEOREF RECORD

Field, chemical, and physical constraints on mafic-felsic magma interaction in the Lamarck Granodiorite, Sierra Nevada, California

Thomas P. Frost and Gail A. Mahood
Field, chemical, and physical constraints on mafic-felsic magma interaction in the Lamarck Granodiorite, Sierra Nevada, California
Geological Society of America Bulletin (August 1987) 99 (2): 272-291

Abstract

Evidence of interaction between magmas of contrasting compositions throughout the crystallization of the Lamarck granodiorite is present in field relations, petrographic observations and major element compositions. The nature of magma interaction is largely a function of the viscosities of the end-members after they had thermally equilibrated. This model is adopted and extended to account for a wide range of initial compositions, T, water contents and crystal contents. Whether magmas mix as liquids, quench as enclaves, or crystallize as large intrusions that hybridize only locally with their host, depends on their rheologies and the manner in which rheologies change during interaction. Mingling is dominant in mixtures having low mass fraction of hot mafic magma at any initial T and crystallinity of the felsic magma. Hybridization becomes likely for large mass fractionation of mafic magma and/or as thermal and compositional contrasts between interacting magmas decrease.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 99
Serial Issue: 2
Title: Field, chemical, and physical constraints on mafic-felsic magma interaction in the Lamarck Granodiorite, Sierra Nevada, California
Affiliation: U. S. Geol. Surv., Menlo Park, CA, United States
Pages: 272-291
Published: 198708
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 79
Accession Number: 1987-070665
Categories: Igneous and metamorphic petrologyGeochemistry of rocks, soils, and sediments
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, geol. sketch maps
N37°00'00" - N37°10'00", W118°40'00" - W118°30'00"
Secondary Affiliation: Stanford Univ., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 1987
Program Name: USGSOPNon-USGS publications with USGS authors
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