Fluid flow, heat, and mass transfer of barite mineralization in Missouri

Two-dimensional modeling of the Ozark region, incorporating fluid flow and heat and mass transfer, was used to gain a better understanding of barite formation processes. Calibration of the models was achieved by replicating a flow regime of 3.0 m/yr indicative of the Ozark region. The driving force for migration of mineralizing fluid was uplift of the Arkoma basin simulated, in the model by a tilted basin. Topographically driven flow led to a more vigorous flow regime and possible fractures in the St. Francois confining unit allowed fluid transfer up section. A cooling mechanism and a mixing mechanism involving mixing of two brines of contrasting salinities were simulated for barite deposition using the fractured and tilted basin.; A cooling mechanism for barite ore formation was tested by fluxing 7 wt. % salt and 22 wt. % salt fluids at a rate of 0.15 m/yr through a zone of increased permeability to represent a fracture in the confining unit. Barite deposition by cooling was dependent on the initial salinity of the fluid, so only the 22 wt. % salt fluid produced favorable conditions. The two mixing models also led to regional concentration of mineralization in the Southeast and Central Missouri Barite District. The initial salinity of the fluid did not make a difference in the time needed for deposition. Solute conditions representative of barite hosted fluid inclusions were seen between 120,000 to 198,000 years after the second brine was added for both simulations. The dilution mechanism seemed to be more indicative of the Central Missouri Barite District mineralization whereas the mixing mechanism fit the mineralization in the Southeast Missouri Barite District.