Alkali amphiboles from the blueschists of Cazadero, California

Journal of Petrology
By:  and 

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Abstract

Alkali amphiboles from Type III and Type IV metamorphic zones in blueschist facies rocks of Cazadero, California, and from comparable New Caledonian rocks have been characterized by X-ray crystallographic, optical, and chemical methods. The composition of any particular alkali amphibole is strongly controlled by the bulk composition of the host rock. Within the blueschist facies, metamorphic zones are not characterized by changes in amphibole composition. All the alkali amphiboles studied herein belong to the C2/m space group and complete miscibility between glaucophane and riebeckite has been demonstrated for the conditions prevailing during metamorphism in the Cazadero and New Caledonian blueschists. Linear relationships are found between unit-cell dimensions and variations in composition between glaucophane and riebeckite. The alkali amphiboles of glaucophane compositions belong to the high pressure-low temperature series, glaucophane II-riebeckite. Limited miscibility of actinolite in glaucophane may be characteristic of blueschist facies metamorphism.

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Publication type Article
Publication Subtype Journal Article
Title Alkali amphiboles from the blueschists of Cazadero, California
Series title Journal of Petrology
DOI 10.1093/petrology/9.1.105
Volume 9
Issue 1
Year Published 1968
Language English
Publisher Oxford Academic
Description 18 p.
First page 105
Last page 122
Country United States
State California
City Cazadero
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