Temperature and brine type of formation Mississippi Valley Type Pb-Zn ore deposits: constrained by simulation experiments

Abstract

The transformation of kerogen to hydrocarbons in the early stages of oil generation is critical for understanding the resource potential of liquid-rich. Additionally, numerous previous experimental and theoretical studies on Mississippi Valley-Type (MVT) Pb-Zn deposits have shown a close genetic relationship with the hydrocarbon accumulation for their common coexistence with the oil/gas reservoirs in the world. However, the actual mineralization process of Pb-Zn deposits associated with hydrocarbon fluids lacks sufficient theoretical studies. Here, we focus on the MVT Pb-Zn mineralization, primarily on the influence of mineralization temperature and the type of brines, using geochemical simulation experiments to verify the relationship between the hydrocarbon fluids and Pb-Zn ore deposits. To restore the actual metallogenic environment to the maximum extent possible, we found that with increased temperature (80-180oC), the number of mineralization showed an increasing trend, and no ore deposits have been found under 80oC. Furthermore, the expected mineralization process could occur under the brine mixture solution, NaCl+CaCl2, and hardly under the single solution. Therefore, under the geochemical simulation experiments, temperature, brine type, and so on play an essential role in the mineralization process under the participation of hydrocarbon fluid, which could provide the theoretical explanations of their coupling relationship.