揚(yáng)子西緣摩挲營新元古代高分異花崗巖年齡、成因和錫鎢成礦潛力

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Abstract： The Mosuoying granite pluton is situated in the Kangdian Axis in the western Yangtze Block， where tin-tungsten mineralization has developed in the contact zone between granite and carbonate rocks.This study aims to investigate the petrogenesis and ore potential of the pluton through geochronology，whole-rock geochemistry，and Zircon Hf isotopic analysis.The LA-ICP-MS zircon U-Pb ages of the porphyritic biotite granite and fine-grained biotite granite are 842±6Ma and 841±7Ma ， respectively， with zircon εHf（t） values ranging from -10.0 to -2.5 and -16.9 to -3.8 and two-stage model ages TDM2） ranging from 2.35 to 1.89 Ga and2.29 to 1.96Ga .These indicate that the magma were derived from re-melting of ancient crust.The Mosuoying granites are peraluminous and high-K calcalkaline，with high light rareearth element/heavy rareearth element ratios and pronounced negative Eu anomalies. Theyare enriched inSn，Be，W，Rb，K，andThanddepletedinBa，Nb，Sr，P，andTi.Low whole-rock K/Rb，Nb/a， and Zr/Hf ratios，coupled with high Rb/Sr ratios， suggest intense fractional crystallization.Based on these geochemical characteristics，the Mosuoying granites are clasified as highlyfractionated S-type granites.The calculated relative oxygen fugacity values and zircon Ce4+/Ce3+ ratios range from -5.84 to -0.93 （average of -3.72 ）and 0.23 to 14.02 （average of 2.55），respectively， indicating lowoxygen fugacity.The occurrence of greisenization， tourmalinization， and fluoritization inthe Mosuoying granites indicates hydrothermal fluid activity.During ocean-continent subduction， upweling of the asthenosphere triggered re-meltingof ancient crust andthe formation of volatile-rich，highlyfractionated reduced granites，providing conditions favorable for tin-tungsten mineralization.The Neoproterozoic highly fractionated granites in the Mianning-Huili area arethus considered to be a keytarget for further tin-tungsten exploration.

Key Words： Mosuoying pluton;Neoproterozoic； zircon U-Pb dating；Hf isotope；highly fractionated S-typegranite

花崗質(zhì)巖漿是熱液礦床中成礦物質(zhì)和流體的重要來源（Halter et al.，2005; Zajacz et al.，2012）。（剩余50609字）