Publication Date

2013

Document Type

Honors Thesis

Department

Chemistry

Keywords

Metasomatism (Mineralogy), Amphibolite, Subduction zones-California-Santa Catalina Island, Metamorphism (Geology), Trace elements, Garnet

Abstract

Mineralogical rinds surround garnet-amphibolite blocks in a subduction zone mélange on Catalina Island, California. The rinds, which occur in concentric layers, are composed of different amphiboles and similar garnets to those in the garnet+amphibole+rutile blocks. Analyses of compositional chemistry was applied to understanding the mechanism of formation of such mineralogical rinds to examine the role of mechanical mixing, fluid metasomatism, and chemical diffusion. An examination of the mineralogy and chemistry of the samples support a model of high temperature amphibolite blocks chemically diffusing with a contrasting serpentinite matrix at lower temperatures in the presence of a water-rich fluid. Mechanical mixing, as suggested by previous studies on the Catalina Schist, cannot explain the presence of multiple rind layers.

Language

English

Comments

67 p. : col. ill. Honors project-Smith College, 2013. Includes bibliographical references (p. 63-64)

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