Genesis of Pyrite in Clastic Rocks of Deep Salt-Related Strata in the Simao Basin and Its Implication for Potash Mineralization: A Case Study of the Well MK-3

In depth of the Simao Basin (2390 to 2650 m interval), many gray mudstone or carbonate rocks are developed in red salt-related strata, and pyrite crystals found fissure matrix. this study, petrology, mineralogy, element geochemistry, LA-MC-ICP-MS situ sulfur isotope analysis were used constrain genesis pyrite, influence relevant geological activities on potash mineralization was discussed. The results show that: (1) upper part salt layer, particle size ranges from 50 300 μm. crystal morphology is mainly pentagonal-dodecahedral irregularly granular, with a small amount cuboidal pyrite. interlayer between rock salt, 100 μm, octahedral. (2) S/Fe value significantly greater than 2; octahedral cubic less irregular granular close 2. (3) δ34SV-CDT values strata range −15.65‰ 11.81‰, average all samples 0.79‰ 8.20‰. −15.02‰ −6.36‰, an −10.66‰. above indicate that layer formed medium-low temperature hydrothermal environment, ore-forming elements have sources, bacterial sulfate reduction (BSR) thermochemical (TSR) contributions. layers sedimentary origin, comes BSR. At present, there no evidence deep potash-rich bodies, Mengyejing deposit has continued since metallogenic period.