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Fluid Inclusion, Rare‐Earth Element and Stable Isotope Study of Carbonate Minerals from the Pongkor Epithermal Gold–Silver Deposit, West Java, Indonesia
Author(s) -
Warmada I Wayan,
Lehmann Bernd,
Simandjuntak Marolop,
Hemes Herian Sudarman
Publication year - 2007
Publication title -
resource geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 43
eISSN - 1751-3928
pISSN - 1344-1698
DOI - 10.1111/j.1751-3928.2007.000012.x
Subject(s) - geology , calcite , geochemistry , carbonate , hydrothermal circulation , fluid inclusions , quartz , meteoric water , rare earth element , isotopes of oxygen , vein , breccia , mineralogy , magmatic water , isotopes of carbon , chemistry , rare earth , paleontology , environmental chemistry , total organic carbon , organic chemistry , psychiatry , psychology
The Pongkor gold–silver deposit is the largest low‐sulfidation epithermal precious metal deposit in Indonesia, and is of Pliocene age. The deposit consists of nine major subparallel quartz–adularia–carbonate veins with very low sulfide content. Vein infill records five paragenetic sequences, dominated by calcite in the early stage and quartz in the later stage of the hydrothermal evolution. Fluid inclusions in hydrothermal calcite and quartz of all stages indicate a temperature ranging from 180 to 220°C and a meteoric water origin (very low salinity close to 0 wt% NaCl equivalent). Carbon isotope data on calcite display a narrow range from −6.5 to −3.0‰δ 13 C. The oxygen isotope values have a wider range of +4.6 to +10.1‰δ 18 O. The broadly positive correlation of the δ 13 C versus δ 18 O plot suggests that the carbon species, which equilibrated during the formation of calcite, is dominated by H 2 CO 3 not far from equilibrium with HCO 3 − . The abundance of rare earth and yttrium (REY) in carbonate samples is very low (>REY mostly <2 ppm). However, there is always a positive Eu anomaly, which indicates a deeper fluid reservoir at >250°C.