9316504 Baumgartner The project involves a three-year integrated field, geochemical and modelling study to illuminate the crystallization history of siliceous marbles in the Ubehebe Peak (Death Valley, California) contact aureole. Detailed outcrop and aureole scale maps of mineral occurrence (isograd maps), abundance and textures will be made for the siliceous dolomite mineral assemblages. This data set will be complemented with stable isotope and trace element geochemistry of carbonate and silicate minerals within the siliceous dolomite units. Initial interpretations will employ simple one-dimensional models to identify promising outcrops for further study. A 2-D finite element model will be developed which will account for variable-density fluid flow, conductive and advective heat transfer, stable isotope exchange, and simple mineral reactions in the siliceous dolomite system. Results of the study will ultimately lead to qualitative understanding of the evolution of the hydrothermal system associated with the cooling of the intrusion.
