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Magmatic epidote and its petrologic significance

January 1, 1984

Epidote is a major magmatic mineral in tonalite and granodiorite in a belt coextensive with the Mesozoic accreted terranes between northern California and southeastern Alaska. Textural and chemical evidence indicates that epidote crystallized as a relatively late but magmatic mineral that formed through reaction with hornblende in the presence of a melt phase. The observed relations concur with experimental data on crystallization of epidote from synthetic granodiorite at 8 kbar total pressure. Plutonic rocks bearing magmatic epidote must have formed under moderately high pressures, corresponding to lower crustal depths, under fairly oxidizing conditions.

Publication Year 1984
Title Magmatic epidote and its petrologic significance
DOI 10.1130/0091-7613(1984)12<515:MEAIPS>2.0.CO;2
Authors E-An Zen, J. M. Hammarstrom
Publication Type Article
Publication Subtype Journal Article
Series Title Geology
Index ID 70013165
Record Source USGS Publications Warehouse
USGS Organization Eastern Mineral and Environmental Resources Science Center