TY - JOUR
T1 - Release and re-enrichment of invisible gold in arsenian pyrite promoted by coupled dissolution-reprecipitation reactions
AU - Yang, Lin
AU - Wang, Qingfei
AU - Fougerouse, Denis
AU - Xian, Haiyang
AU - Li, Huajian
AU - Wang, Ruixue
AU - Rickard, William D.A.
AU - Groves, David I.
AU - Deng, Jun
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024/12
Y1 - 2024/12
N2 - The mechanisms responsible for invisible gold enrichment driven by coupled dissolution-reprecipitation reaction (CDR) are debated. Here we report the micro- to nano-scale textures of arsenian pyrite in a high-grade (>10 g/t) gold ore from the Chang’an deposit to trace the gold enrichment process. Our study records a CDR-driven evolution of mineral growth from an As-rich, Au-poor pyrite core, with numerous fine arsenopyrite inclusions, to an inclusion-free, As-Au-rich oscillatory pyrite rim. The reaction occurred at ~260 °C under 4.7 to 5.8 pH and –36.6 to –32.9 logfO2 conditions. The elevated As but depleted S contents in the pyrite core indicate a combined elevation of S fugacity and solubility of Au. The coprecipitation of arsenopyrite inclusions in the core caused a depletion of S fugacity to –13.8 ~ –11.7, triggering Au enrichment in the rim. This non-unique process has the potential to explain the upgrade of invisible Au in arsenian sulfides, worldwide.
AB - The mechanisms responsible for invisible gold enrichment driven by coupled dissolution-reprecipitation reaction (CDR) are debated. Here we report the micro- to nano-scale textures of arsenian pyrite in a high-grade (>10 g/t) gold ore from the Chang’an deposit to trace the gold enrichment process. Our study records a CDR-driven evolution of mineral growth from an As-rich, Au-poor pyrite core, with numerous fine arsenopyrite inclusions, to an inclusion-free, As-Au-rich oscillatory pyrite rim. The reaction occurred at ~260 °C under 4.7 to 5.8 pH and –36.6 to –32.9 logfO2 conditions. The elevated As but depleted S contents in the pyrite core indicate a combined elevation of S fugacity and solubility of Au. The coprecipitation of arsenopyrite inclusions in the core caused a depletion of S fugacity to –13.8 ~ –11.7, triggering Au enrichment in the rim. This non-unique process has the potential to explain the upgrade of invisible Au in arsenian sulfides, worldwide.
UR - http://www.scopus.com/inward/record.url?scp=85192734296&partnerID=8YFLogxK
U2 - 10.1038/s43247-024-01408-5
DO - 10.1038/s43247-024-01408-5
M3 - Article
AN - SCOPUS:85192734296
SN - 2662-4435
VL - 5
JO - Communications Earth and Environment
JF - Communications Earth and Environment
IS - 1
M1 - 241
ER -