STRUCTURE AND STABLE ISOTOPE SYSTEMATICS OF THE FARNHAM DOME, SE UTAH
This study seeks to determine whether the presence of calcite in the FD is related to leakage of CO2 due to seal failure or precipitation associated with faulting during deformation. Approximately 120 calcite samples were collected in the field and from one core penetrating the Mesozoic and Paleozoic reservoirs. Preliminary δ13C and δ18O data cluster from -5.57 to -7.37‰ and from 17.96 to 18.59‰, similar to syndeformational veins found in the Green River and Moab areas to the southeast. Structural data document a complex fracture system related to fold geometry and bedding. Sub-vertical calcite-filled fractures bisect NW-SE trending sets of conjugate shear fractures with a strike-slip sense of displacement perpendicular to bedding are common on the fold limbs. Conjugate sets of reverse and normal faults trending parallel to the fold axis and at high angles to bedding, compactions bands, and en echelon vein arrays are found in association with areas of the fold where deformation is greatest. We interpret clustering of stable isotope data, association of calcite with shear sets, and structural data as indicating calcite precipitation from a single fluid reservoir during deformation.