Evidence for syngenetic gold mineralization overprinted by skarn at the Xinqiao Cu-S-Fe-Au deposit, Tongling Mineral District, China

The Xinqiao Cu-S-Fe-Au deposit is located in the northeast of the Tongling mineral district, central part of the Middle and Lower Yangtze River region in eastern China. This study presents the mineral paragenesis and pyrite chemistry of Xinqiao. Four types of pyrite are recognized at Xinqiao: Pyrite I – colloform pyrite, pyrite II – recrystallized pyrite from pyrite I, and pyrite III – finemedium grain pyrite occurring disseminated in retrograde skarn or wall rocks, pyrite IV – coarse grained massive pyrite, which makes up the main sulfur orebody at Xinqiao. Trace element concentrations in pyrite were measured by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and the results are also reported. The paragenetic, textural, and geochemical results from Xinqiao suggest that a stratiform sulfide deposit was modified during skarn formation associated with late Yanshanian magmatic hydrothermal activity.