Study On The Crust-Mantle Interaction Of Metallogenic Processe Of Hehuaping Tin-Polymetallic Deposit In Southern Hunan

Hehuaping tin-polymetallic deposit lies in major tungsten-tin-polymetallic deposit-concentrated area is a large deposit discovered in recent years, and was first said that the tin mineralization occurred in Indosinian for southern Hunan. What is more, there was the late mineralization of late Yanshanian period in Huhuaping area. Yet have not been reported on the genesis and the formation mechanism of the deposit.On the basis of field investigation, the paper is focus on the geochemical characteristics, petrogenesis, tectonic setting of the magmatic rocks and mineralization characteristics, the geochemical characteristics of ore-forming fluids in Hehuaping area by the methods and measures of Sr-Nd isotopic, zircon Hf isotope, fluid inclusions, He-Ar-Ne isotope and so on, and achieved the following main understanding:(1)Wangxianling granites are composed of the medium coarse tourmaline-biotite granite formed in about235Ma and the middle-fine grain biotite granite formed in about212Ma. The major, trace and REE element geochemistry and the Sr-Nd, Lu-Hf isotopic data indicate that the Wangxianling granites were mainly derived from the Mesoproterozoic crustal materials, and the newly mantle-derived components, despite small in proportion, might have been involved in the granites generation. The Wangxianling granites were formed in the tectonic setting of the extension and thinning of the continental crust and the underplating of basic magma after the crust had been thickened. The Rb-Sr isochron of the whole rock of the Wangxianling early granite is202±18Ma(95%confidence, MSWD=1.3), which represents the time when it had crystallized at last.(2) the major, trace and REE element geochemistry indicates that the granite porphyries of early Yanshanian are similar to the alumious A-type granite, and further classified to A2type. The Sr-Nd, Lu-Hf isotopic data indicates that their source were mainly derived from the Mesoproterozoic crustal materials and a part of the newly mantle-derived components or juvenile components were involved, the mantle component of the granite porphyry source is about24%in proportion. The granite porphyries were formed in the tectonic setting of the extension and thinning of the continental crust and upwelling of the asthenosphere.(3) The high3He/4He ratio(0.15to2.49Ra) and the fluid inclusion is rich in CO2(6%to36%) indicates that mantle fluids have been participated in the Indosinian metallogenic processe.(4) the ore-forming materials of Indosinian and Yanshannian both were derived from multiple sources, and the ore-forming fluids both were mixed with mantle, crust and atmospheric water. Mantle materials were involved in the Indosinian diagenetic and metallogenic, the diagenetic age(235Ma) and the metallogenic age(224Ma) are basically in accord with the mafic enclaves age(224Ma) in Daoxian of southern Hunan, which indicates that the Mesozoic tectonic regime transformation (extruded thickening to stretching thinning) for Nanling region may occur in the Late Triassic and the time is earlier than the Jurassic was presented by the predecessors.