Date of Award

Spring 1-1-2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geological Sciences

First Advisor

Joseph R. Smyth

Second Advisor

Stephen J. Mojzsis

Third Advisor

Alexis S. Templeton

Abstract

The entire water budget of the Earth's mantle may be dominated by nominally anhydrous minerals; materials that can incorporate <5-600 ppm H2O in natural samples. Due to their structural similarities, the local structural environment of H in the humite minerals provides a useful model for the incorporation of H into olivine. Since the humite are breakdown products of serpentine, and potentially transform into olivine in the upper mantle, humites may play a significant role in the transport of water to the mantle. Four crystals of chondrodite, clinohumite, norbergite, and humite, both natural and synthetic, were analyzed via Raman spectroscopy and electron microprobe analysis to gain insight into their chemical compositions. Their structures were refined by single-crystal X-ray diffraction analysis in order to gain insight into the effects of hydration on the structures. The new data confirm earlier studies of cation ordering and hydration geometry, and enhances our understanding of the crystal chemistry of the humite minerals, particularly the geometry of the H position. In humite, hydrogen was found to occupy the H1 site.

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Geology Commons

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