Two-garnet rodingite from Amador County, California

W. A. Duffield; M.H. Beeson

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USGS · 70159466

Two-garnet rodingite from Amador County, California

W. A. Duffield·M.H. Beeson

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Abstract

Two distinct phases of garnet have been discovered in rodingite from Amador County, Calif. The two garnets are hydrogrossular and (hydro?) grossular-andradite. Only one, generally hydrogrossular, has been reported in rodingitcs studied by other workers. The rodingite of this study formed from a mafic dike with abundant euhedral plagioclase laths. The hydrogrossular is concentrated within the areas of these laths and is volumetrically about as abundant. The (hydro?) grossular-andradite is concentrated in the groundmass and as incursions into the plagioclase laths. The garnets apparently grew during one general episode of metasomatism, and their spatial distribution and compositions were controlled principally by the unequal distribution of iron and aluminum caused by the presence of plagioclase laths (and mafic minerals?) in the original unaltered dike.

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

Source-reported bounding extent: 38.28993659801203° to 39.487084981687495° latitude; -121.47583007812501° to -119.92675781249999° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

W. A. Duffield, M.H. Beeson. 1973. Two-garnet rodingite from Amador County, California. https://pubs.usgs.gov/publication/70159466

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