Carbonate-hosted sulfide mineralization in the Southwest Davis Zinc Field, Southern Oklahoma

The Southwest Davis Zinc Field (SDZF) consists of a small (16 km 2) group of zinc sulfide deposits, and associated dolomitization and dolomite cementation, adjacent to the Arbuckle Mountains along the Washita Valley Fault Zone in Southern Oklahoma. The SDZF may represent Mississippi Valley Type (MVT) mineralization, which is part of a much larger fluid system that may have affected rocks over a very wide geographical area or alternatively, a basement related hydrothermal system of a more localized extent. The purpose of the study was to examine epigenetic mineralization at several localities to identify the source(s) of mineralizing fluids and to determine whether or not they were regionally distributed basinal brines, locally convected epigenetic fluids, or a combination of the two. This was accomplished by characterizing the fluid and diagenetic history at each locality to determine if, and to what extent hydrologic connectivity existed between and among locations during the mineralizing event(s). There are no notable paragenetic differences among localities. Petrography, stable isotope and microthermometric data indicate that diagenetic processes were sedimentologically, geochemically, and structurally consistent across the study area. Dolomitization and ore mineralization in the area appears to be related to faulting and brecciation along the trend of the Arbuckle Anticline. Mineralization occurred from a convective flow system in which basement-influenced brines entered the host formations through faults and circulated throughout the brecciated zone. The data indicate a localized system in which mineralization is not the result of a complex mixing of fluids . The narrow range of measured Th and salinity values indicate a system with one or possibly two fluids.