Mineralogy of Siliceous Hot Springs Deposits: Comparing Earth and Mars Intern Vicki Mills Mentor Prof. Jack Farmer (Ruff, 2008) Opaline Silica Deposits (> 90 % Silica ) Mini-TES Spectra ( Ruff, S., J. Farmer, W. Calvin et al Evidence for possible siliceous sinter at Home Plate in Gusev Crater Eos Transactions, American Geophysical Union, Fall Meeting Suppl, Abstract, P23A-1097 ) Transformational Sequence for Silica (SiO 2 ) Polymorphs Opal-A ( SiO 2.n H 2 O ) Opal-C/T Quartz AmorphousParacrystalline Microcrystalline Preservation Potential Low High Decrease in porosity, permeability & structural H theta peaks: 20-242-theta peaks: 20.8 2-theta curve: centered at 22 Opaline Silica (Opal-A) forms in Hot Spring Environments Study Locations : Excelsior Geyser, Yellowstone National Park, Wyoming Orakei Korako, Orakei Korako, New Zealand New Zealand Steamboat Springs, Nevada Steamboat Springs, Nevada X-Ray Powdered Diffraction (XRPD) Sample Preparation Sample Preparation Mortar & Pestle Mortar & Pestle Sieved 150 m Sieved 150 m Run Conditions Run Conditions Siemens D-5000 Siemens D kV at 30mA 40kV at 30mA CuK Radiation CuK Radiation Step size Step size For JADE Analysis Sample Preparation 3g sample g ZnO Crushed