Multiple Isotopic Constraints on the Origin of the High-Grade Chaxi Gold Deposit in the Jiangnan Orogenic Belt, South China

作者：Shuling Song, Yu Zhang, Robert A. Creaser, Huayong Chen, Changzhou Deng, Matthew J. Brzozowski, Runsheng Yin, Jonathan Toma, Yongjun Shao, Hongbin Li, Xu Wang · 发表于：Economic Geology · 年份：2025 · DOI：10.5382/econgeo.5153 · 被引用次数：7 · 研究领域：Geochemistry and Geologic Mapping、Geological and Geochemical Analysis、Geochemistry and Geochronology of Asian Mineral Deposits

Abstract The Jiangnan orogenic belt in South China is known for its numerous gold deposits that are hosted by Precambrian low-grade metamorphic rocks that were reworked during Paleozoic and Mesozoic orogenic events, which resulted in multiple epochs of gold mineralization. The Chaxi gold deposit, located in southwestern Hunan in the central portion of the Jiangnan orogenic belt, is characterized by localized ultrahigh-grade gold mineralization (visually estimated to be up to several tens of percent). Despite its economic significance, the timing of formation, gold enrichment processes, and origin remain ambiguous; yet these are critical for both exploration and our understanding of gold metallogenesis in the Jiangnan orogenic belt. In addition to the pre-ore quartz-sericite-pyrite stage (stage I), several vein stages associated with primary gold mineralization and alteration have been identified at Chaxi: stage II quartz-chalcopyrite-electrum veins with pyrite alteration, stage III quartz-dolomite-polymetallic sulfides-native gold veins with sericite alteration, and stage IV quartz-dolomite-polymetallic sulfides-native gold veins with chlorite alteration. A supergene stage (stage VI) containing secondary gold mineralization is also present. The Ar-Ar age of sericite in stage I and the Re-Os age of molybdenite-galena intergrowths in stage II are 430.4 ± 2.7 Ma (plateau age; mean square of weighted deviates [MSWD] = 0.82) and 430.6 ± 1.1 Ma (weighted mean model age; MSWD = 0.38...