Date of Award

12-2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Geology

Major Professor

Theodore C. Labotka

Committee Members

David R. Cole, David B. Finkelstein, Harry Y. McSween, Claudia J. Rawn

Abstract

Geochemical processes involving the interaction of fluids and minerals occur in nearly every environment on the surface and in the crust of the Earth. The variety of fluid–mineral processes on the Earth is quite diverse, and these various processes can occur under a large range of geochemical conditions. Aqueous dissolution and alteration, hydration, protonation, solution–precipitation, diffusion, and fluid and isotope exchange are among the many fluid–mineral interaction processes that contribute to the overall cycling of elements on Earth. This dissertation uses analog experiments to examine fluid­–mineral interaction processes found in different geological environments and under a range of environmental conditions. The first part of this dissertation examines the reactive and diffusive exchange of oxygen isotopes that results from performing a dolomite breakdown experiment under a temperature, pressure, and fluid condition analogous to a contact metamorphic environment. The second two parts of the dissertation involve the development of new methods for the growth of nanocrystalline fayalite and intermediate composition olivine. The final two parts of this dissertation focus on the interaction of olivine with either H2O or acidic solutions (0.005 M H2SO4 or 0.01 M HCl) at low temperature and pressure. The first of these two parts experimentally uses different surface area olivine powders that are reacted with low pH fluids in non-buffered, closed system experiments where pH and solution composition are allowed to change. The second of these two parts uses various analytical techniques that can examines changes to the surfaces of olivine single crystals at the nanoscale resulting from experiments performed under environmental conditions where the fluid–mineral interaction transitions from dissolution at low temperature and pressure to alteration at moderate temperature and pressure. Though the individual projects contained within this dissertation are varied, they share the common theme of using experiments to examine fluid­–mineral interaction processes.

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