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The Huangshaping deposit is unique in southern Hunan Province, China, as it hosts economic reserves of both W–Mo and Pb–Zn mineralization, which are usually associated with granite and granodiorite porphyry in this area, respectively. This study reports results of in situ LA-MC-ICP-MS sulphur isotopic composition analyses conducted on sulphides from both W–Mo and Pb–Zn mineralization from the Huangshaping deposit with the aim of constraining ore genesis for this deposit. All samples from the proximal W–Mo mineralization have relatively uniform and high δ34S values (8.7 ‰ to 16.0 ‰), close to the range for carbonate sediments in this deposit (13.8 ‰ to 18.1 ‰). These patterns suggest that the granite porphyry in this deposit was the sulphur source for W–Mo mineralization, and that the assimilation of evaporite from the carbonate sediments led to the high δ34S values of the granite porphyry. Sulphides from the Pb–Zn mineralization have δ34S values (2.2 ‰ to 10.3 ‰) lower than those of the W–Mo mineralization, and generally increase in this paragenetic order, with the lowest δ34S values being similar to those of the basement (3.8 ‰ to 7.7 ‰). These patterns indicate that the original sulphur for the Pb–Zn mineralization was most likely derived from the basement, with input of sulphur from the carbonate sediments increasing during the evolution of ore-forming fluids. On the basis of the measured sulphur isotopic compositions, it is suggested that the ore-forming materials for the W–Mo mineralization were derived from the granite porphyry, whereas ore-forming materials extracted from the basement dominated the Pb–Zn mineralization. [ABSTRACT FROM AUTHOR]

The Baotan tin deposit (23 Mt @ 0.43% Sn) is located in the Jiuwandashan–Yuanbaoshan area, South China. It is hosted in Neoproterozoic mafic/metasedimentary rocks and apical portions of the Pinying granite pluton. Six alteration and mineralization stages have been identified: pre-ore alteration, cassiterite greisen, cassiterite–tourmaline–quartz vein, cassiterite–quartz vein, cassiterite–sulfide vein, and post-ore quartz/calcite–quartz vein stages. Tin mineralization is mainly in the cassiterite greisen, cassiterite–tourmaline–quartz, and cassiterite–quartz vein stages. The deposit is characterized by widespread tourmalinization. Both pre-ore and ore-stage tourmaline is schorl. Tourmaline from pre-ore tourmaline–quartz nodules has elevated Al2O3 and F contents and Fe/(Fe + Mg) and Na/(Na + Ca) ratios, which are probably controlled by the initial magmatic fluid. Ore-stage tourmaline shows low Al2O3 and F contents and Fe/(Fe + Mg) and Na/(Na + Ca) ratios, which are likely influenced by the surrounding mafic rocks. LA–ICP–MS U–Pb dating on two cassiterite samples from disseminated cassiterite–tourmaline–quartz ore and cassiterite–quartz vein yields 206Pb/238U weighted mean ages of 832 ± 5 Ma and 834 ± 4 Ma (2 σ), respectively. These two dates are consistent with the previously reported zircon U–Pb ages of 834–835 Ma for the Pingying granite, which indicates that tin mineralization is related to the granite. The granite has low magnetic susceptibility and zircon Ce4+/Ce3+ ratios, which are similar to those of Sn-bearing ilmenite-series granites. Our study confirms the Neoproterozoic tin mineralization event in South China and indicates that the Neoproterozoic highly fractionated S-type granites in the southeastern margin of Yangtze Block have a great potential for tin mineralization. [ABSTRACT FROM AUTHOR]

Southern Hunan Province, located in the Cathaysia Block where the Shi–Hang zone and Nanling belt meet, is characterized by extensive Mesozoic magmatism and coeval polymetallic mineralization. The Huangshaping W–Mo–Pb–Zn–(Cu) deposit is representative in this area. However, the petrogenesis of the granitoids associated with the Huangshaping deposit, and their relationships with mineralization, remain undetermined. In this paper we focus on zircon U–Pb dating, whole-rock geochemistry, and Sr–Nd–Pb–Hf isotopic compositions in order to further our understanding of these issues, as well as their regional implications. The Huangshaping granitoids are characterized by two pulses of intrusive activity: a first-stage quartz porphyry and a second-stage felsite and granite porphyry, our new data show that the quartz porphyry and felsite formed at 160.5 ± 1.3 and 156.6 ± 1.4 Ma, respectively, representing a period of Late Jurassic magmatism. Granitic enclaves within the quartz porphyry crystallized at 160.2 ± 1.6 Ma, and zircons and apatites from the enclaves exhibit Hf isotopic and geochemical compositions that suggest a Palaeoproterozoic lower crustal melt as one end-member of the magma that formed the quartz porphyry, whereas another likely end-member was coeval mantle-derived magma, as indicated by the geochemistry and Sr–Nd–Pb–Hf isotopes. However, both the felsite and granite porphyry were probably derived from the melting of metamorphic basement rocks in the upper crust. The felsite clearly formed as a result of the rapid ascent and cooling of magma, whereas the granite porphyry underwent fractional crystallization. The magma sources and evolution of the granitoids, as well as their association with the Huangshaping mineralization, suggest that melting of upper crustal components controlled the W–Mo and Pb–Zn mineralization, whereas dehydration of a subducted slab provided the Cu mineralization in southern Hunan Province. [ABSTRACT FROM PUBLISHER]

The article discusses apatite in granitoids rock of polymetallic deposits in Southeast Hunan Province, China and its petrogenesis and metallogenesis. Topics discussed include chemical compositions of apatite in granitic rock which related to ore deposit, diagrams related to chondrite-normalized rare earth elements distribution models of apatites from southeast Hunan, and association of magmas with addition of mantle material as partial melting of sedimentary rocks.

The area of southeastern Hunan Province, China, located within the southwestern part of the Shi–Hang metallogenic zone, is characterized by abundant Cu–Pb–Zn, W, and Sn polymetallic ore deposits that are closely associated with coeval late Mesozoic granodiorite porphyries and biotite granites, respectively. Here, we present new major and trace element concentrations and 87 Sr/ 86 Sr ratios of apatites from six ore-bearing granitic rocks, as determined by electron microprobe, laser ablation–inductively coupled plasma-mass spectrometry, and thermal ionization mass spectrometer, which allow us to determine the main controls on the formation of these different types of mineralization and to explore how these controls are reflected in variations in apatite chemical and isotopic compositions. The apatite data indicate that granodiorite porphyry intrusions related to Cu–Pb–Zn mineralization are oxidized and formed as a result of slab dehydration, melting of the mantle wedge overlying a subducted slab, and the partial melting of crustal material. The release of abundant Cl- and H 2 O-rich fluids from the slab triggered mantle melting and the extraction of metals that were precipitated within the deposits. In comparison, granites related to W and Sn deposits are moderately oxidized to reduced, and were generated by the partial melting of crustal material with only limited input from mantle-derived magmas. Granites associated with the W and Sn mineralization formed in an intra-arc rifting-related tectonic environment. The fact that these numerous polymetallic ore deposits formed in the same area during two successive periods of mineralization, the first from 180 to 160 Ma and the second from 160 to 140 Ma, indicates that the tectonic environment of southeastern Hunan Province evolved from a continental arc associated with the subduction of the Paleo-Pacific Plate and the formation of Cu–Pb–Zn deposits to a later intra-arc rifting environment associated with the formation of W and Sn deposits as a consequence of slab roll-back and mantle upwelling during the Late Jurassic. This study reveals that apatite compositions can be used as a proxy to reflect the differences between granitoids and their associated mineralization, and identify regional metallogeny and tectonic evolution. [ABSTRACT FROM AUTHOR]