The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned disciple. iii Hirner, Sarah Marie (M.S., Geology, Department of Geological Sciences) The structure and hydration of the humite minerals Thesis directed by Professor Joseph R. Smyth The entire water budget of the mantle may be dominated by nominally anhydrous minerals. The local structural environment of H in the humite minerals could provide a valuable model for the incorporation of H into olivine due to their structural similarities. It also thought that humites may play a significant role in the transport of water into the mantle. Four crystals of chondrodite, clinohumite, norbergite, and humite, both natural and synthetic, have been analyzed via Raman spectroscopy and electron microprobe analysis. Their structures have been refined by single-crystal X-ray diffraction analysis. The new data confirms earlier studies of cation ordering and hydration geometry, and adds new insight into the crystal chemistry of the humite minerals, particularly the geometry of the H position. In humite, hydrogen was found to occupy the H1 site. iv ACKMOWLEDGEMENTS This research was supported in part by National Science Foundation grants to Joseph R. Smyth
