| This thesis characterizes the fracture-controlled paleohydrologic systems around two salt diapirs (Onion Creek and Bakio) that developed in different geological settings (terrestrial and marine). Structural data and vein and host rock samples were collected around each diapir. Samples were analyzed petrographically, and geochemically. Field measurements constrained fluid transport systems while petrographic analyses defined the sequence of vein mineral precipitation. Stable isotope, fluid inclusion and elemental analyses were used to determine the sources, temperatures and compositions of the paleofluids. The data from Onion Creek suggest there were deep, moderate, and shallow depth paleohydrologic systems. These systems are interpreted to have contained deep basinal brines, highly-saline fluids, and shallow meteoric fluids. The data from Bakio suggest there was an early and late fluid system. Both systems consisted of locally derived fluids with high-fluid to rock ratios, but the later system may have been more meteoric in origin. |
