Mineralization processes involved in the formation of the Jinya Carlin-type Au deposit, northwestern Guangxi, China: Evidence from in situ trace element and S isotope geochemistry of Au-bearing zoned pyrite

Abstract The Jinya Au deposit is a representative example of the Carlin-type Au mineralization located within the “Golden Triangle” area of the Yunnan, Guizhou, and Guangxi provinces, China. The deposit is located within a fault zone at the contact between a carbonate platform and contains Au mineralization hosted by arsenopyrite and pyrite, with the latter providing evidence of changes in fluid composition during pyrite growth. Back-scattered electron (BSE) images indicate that this Au-bearing zoned pyrite can be divided into dark cores (Py1), lighter colored central sections (Py2), and dark rims (Py3). Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) and secondary ion mass spectrometry (SIMS) analyses provide information on compositional and S isotopic variations within this pyrite. These data indicate that each pyrite zone is compositionally homogeneous, showing Co/Ni ratios of