Sulfur isotopes and geochemistry of sulfate and sulfide minerals in the Mountain Pass Intrusive Suite, 2025

Sulfur minerals, including sulfates (barite, celestine) and sulfides (pyrite, galena, chalcopyrite) are common throughout the Mountain Pass carbonatite. Changes in the sulfur isotope chemistry of sulfate and sulfide minerals record changes in temperature and oxygen fugacity in the system from which they precipitate, and early primary sulfate and/or sulfide minerals may record the primary signature of sulfur in the carbonatite melt. Sulfate and sulfide minerals are analyzed here to constrain the source and evolution of the Mountain Pass system. The dataset includes whole rock geochemistry for the samples from which sulfate and sulfide minerals were analyzed, as well as mineral geochemistry collected via electron microprobe and laser ablation ICP-MS and sulfur isotope composition collected via laser ablation MC-ICP-MS for sulfate and sulfide minerals in the Mountain Pass Intrusive Suite.