Cyclic Magmatic-Hydrothermal Evolution in Porphyry Systems: High-Precision U-Pb and Re-Os Geochronology Constraints on the Tibetan Qulong Porphyry Cu-Mo Deposit

摘要

We present high-precision chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon and isotope dilution-negative-thermal ionization mass spectrometry (ID-N-TIMS) Re-Os molybdenite geochronology of the world-class Tibetan Qulong porphyry Cu-Mo deposit. The data is used to constrain the timing, duration, and to yield implications for the ore-forming processes. The U-Pb data suggest that the preore Rongmucuola pluton crystallized at 17.142 ± 0.014/0.014/0.023 Ma (uncertainties presented as analytical /+ tracer /+ decay constant uncertainties), with emplacements of the synore P porphyry and postore quartz diorite occurring at 16.009 ± 0.016/0.017/0.024 and 15.166 ± 0.010/0.011/0.020 Ma, respectively. The Re-Os analysis of multiple independent molybdenite separations from single molybdenite-bearing quartz veins yields sub-‰ level analytical precision (