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Yuan Y.B.,China University of Geosciences | Yuan S.D.,Chinese Academy of Geological Sciences | Chen C.,Southern Hunan Institute of Geology and Survey | Huo R.,Southern Hunan Institute of Geology and Survey
Acta Petrologica Sinica

The Huangshaping polymetallic deposit is the largest lead-zinc mine in Hunan Province. There are various kinds of magmatic rocks distributing in this mining area, associated with W-Sn-Cu-Pb-Zn-Ag polymetallic mineralization. It's also a reprensitative deposit in southern Hunan with porphyry-skarn-vein Cu-Pb-Zn-Ag and W-Sn polymetallic superimposed mineralization. To clarify the geochronological framework and source characteristics of Huangshaping granitoids, and to address the temporal relationship between magmatism and mineralization, three types of granite including dacite porphyry, monzogranite porphyry and quartz porphyry, and the enclaves hosted in the quartz porphyry in Huangshaping were collected for zircon U-Pb dating and Hf isotope analysis. The results show that the zircon U-Pb ages of the dacite-porphyry, monzogranite porphyry and quartz porphyry are 158.5 ± 0.9Ma, 155.2 ± 0.4Ma and 160.8 ± 1.0Ma, respectively. The zircon U-Pb age of the enclave hosted in the quartz porphyry is 220.4 ± 1.2 Ma. The inherited zircons cores that yield Paleoproterozoic and Neoproterozoic ages were found in the monzogranite porphyry. Igneous zircons of Middle-Late Jurassic have low and similar εHf (t) values of - 7.6 ∼ - 3.2 and Mesoproterozoic (1.7-1.4Ga) depleted-mantle model ages, which is interpreted to reflect derivation from old crust source. Those old zircons yield positive εHf(t) values of 0.5 ∼ 6.5 and negative of - 1.5 ∼ -0.07, suggesting involvement of the depleted mantle source in the magma generation. The zircon U-Pb dating and Hf isotope analysis of different kinds of granitoids in ore district imply that they had a cognate origin related to partial melting of ancient continental crust. These data also provide important evidence for temporal-spatial connections of emplacement of the granitiods and W-Sn-Cu-Pb-Zn-Ag polymetallic mineralization in the Huangshaping mining area. In addition, U-Pb ages of the inherited zircon cores indicate that this area has undergone a complex magmatic history, which maybe the crucial reason of the formation of Cu-Pb-Zn-W-Mo-Fe polymetallic deposit. Source

He H.,Chinese Academy of Geological Sciences | Wang D.,Chinese Academy of Geological Sciences | Su X.,China University of Geosciences | Zhang Y.,Southern Hunan Institute of Geology and Survey | And 4 more authors.
Geotectonica et Metallogenia

The Qitianling granites in Chenzhou city, Hunan province, is a Mesozoic batholith. In this study, granitic rock samples across the Qitianling Geological-Geochemical-Geophysical profile were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to measure the concentrations of rare metal elements, including Li, Rb, Sr, Cs, Nb, Ta, Be, Zr, Hf. The results showed that: (1) samples are significantly enriched in Li, Rb, Cs, Be and Zr, which are higher than the average concentrations of granite in South China, while elements like Sr, Nb and Ta are relatively depleted; (2) the concentrations of elements like Li, Rb, Cs increase gradually from west to east of the batholith, while the concentrations of Sr is gradually decrease. Elements like Nb, Ta and Hf remain stable except occasional "peak value"; (3) compared with the neighborhood Xianghualing pluton that is genetically related to the Xianghualing rare metal deposit, the Qitianling batholith is of the same geological stage, but the rare metal contents in Qitianling are not so high as to be a potential or as a target for exploration. That is to say, it is difficult to find new rare metal deposits as those formed around the Xianghualing pluton, considering the rare metal contents and stronge erosion of the Qitianling batholith. Based on the geophysical and geological characteristics of the rocks, it is considered that the Qitianling batholith was intruded from southeast to northwest, which might be the cause of rare element zonation across the Qitianling batholith. Source

Guo C.,Chinese Academy of Geological Sciences | Chen Z.,Chinese Academy of Geological Sciences | Lou F.,Jiangxi Provincial Institute of Geological Survey | Xu Y.,Southern Hunan Institute of Geology and Survey
Geotectonica et Metallogenia

Late Jurassic, especially 150-160 Ma, is the most important period of W-Sn polymetallic mineralization in the Nanling region. The ore bearing granitoids are alkaline and high-potassium, and their major and trace element concentrations and Sr-Nd isotopic compositions are reviewed in this contribution. The ore bearing granites can be divided into two subgroups which are characterized by "sea-gull type-" and "inclining type-" REE patterns. Moreover, the two subgroups show distinct major and trace element and Sr-Nd isotopic characteristics. Ca/(Mg+Fe) vs. Al/(Mg+Fe) diagram shows that the two subgroups of granites were derived from different sources. SiO2 vs. P2O5, Rb vs. Y and Rb vs. Th diagrams also demonstrate that the W and Sn bearing granites are of different genetic types. Source

Zhang R.-Q.,Nanjing University | Lu J.-J.,Nanjing University | Wang R.-C.,Nanjing University | Yang P.,Geological Institute of Yunnan Nonferrous Geological Bureau | And 6 more authors.
Ore Geology Reviews

The Nanling Range in South China hosts numerous W-Sn-rare metal deposits associated with several cycles of polygenetic granitic intrusions. In the Wangxianling area of the middle Nanling Range, igneous intrusions include the Wangxianling and Hehuaping granite plutons and more than 20 granite porphyry dykes. The Wangxianling pluton has a central phase of medium-grained tourmaline two-mica granite and a marginal phase of medium-grained tourmaline muscovite granite. The pluton hosts several tungsten deposits including Shuiyuanshan and Yejiwo. Mineralization type is dominantly scheelite greisen, with subordinate scheelite skarn and wolframite-quartz veins. The Hehuaping pluton composed of coarse-grained biotite granite and granite porphyry dykes to the east of the Wangxianling pluton have an associated Hehuaping tin deposit with tin skarn and subordinate porphyry and greisen mineralization.In situ zircon and cassiterite U-Pb dating, molybdenite Re-Os and muscovite 40Ar-39Ar dating techniques are used to refine the age spectra of granitic rocks and W-Sn mineralization in the Wangxianling area. Granites of the Wangxianling pluton have zircon U-Pb ages of ~224Ma. Tungsten-bearing quartz veins from both the Shuiyuanshan and Yejiwo tungsten deposits have an average molybdenite Re-Os isochron age of ~224Ma, and muscovite of scheelite greisen from the Shuiyuanshan tungsten deposit yields a 40Ar-39Ar plateau age of 214Ma. The two mineralization ages are consistent with the zircon U-Pb age of the Wangxianling pluton indicating a close association between pluton emplacement and W mineralization in the Late Triassic. Both the Hehuaping pluton and granite porphyry dykes have zircon U-Pb ages of ~156Ma. In situ LA-ICP-MS U-Pb dating of cassiterite in both the tin skarn and tin greisen yields an average age of ~156Ma, showing that the Sn mineralization occurred at a similar time to the Late Jurassic granitic magmatism. Thus, two mineralization events are identified in the Wangxianling area, and include an earlier W dominant mineralization event and a later Sn dominant mineralization event. The earlier event is related both spatially and temporally to intrusion of the Late Triassic S-type Wangxianling granite pluton, whereas the later mineralization is associated both spatially and temporally with intrusion of the Late Jurassic Hehuaping A2-type granite pluton and A2-type granite porphyry dykes. © 2014 Elsevier B.V.. Source

Li J.-K.,Chinese Academy of Geological Sciences | Wang D.-H.,Chinese Academy of Geological Sciences | Liang T.,Changan University | Xu Y.-M.,Southern Hunan Institute of Geology and Survey | And 10 more authors.
Acta Geoscientica Sinica

In this paper, through a comparative study of the geological and geochemical features of the typical ore concentration areas, the authors summarized the evolution of the crust and regional metallogenic regularities in the western, middle and eastern regions of the Nanling metallogenic belt. In the western region, magmas intruded into the late Paleozoic and early Mesozoic crust in a short time with an explosive type Sn mineralization in late Yanshanian epoch; in the middle region, magmas intruded into the late Paleozoic crust for a long time accompanied by polymetallic and multi-stage mineralization; in the eastern region, magmas intruded into early Paleozoic crust with the W mineralization peak in Yanshanian epoch, indicating that W mineralization might have occurred in the early Paleozoic crust of the western Nanling region. Correspondingly, the concealed granite, the Shizhuyuan-type deposit under Huangshaping type deposit, and the "basement" under the "five-storey" type W deposit should be the deep exploration targets in the western, middle and eastern Nanling regions, respectively. In addition, the deep exploration across the Qitianling intrusion in southern Hunan Province shows the existence of an upwelling pathway for mantle material indicated by artificial earthquake test at the center of the intrusion, where the later fine-grained granite contained more mantle material than the early coarse-grained granite in the light of Os isotope. In addition, the Sn-rich rhyolite subvolcanic rock vein that intruded into the early coarse grained granite in the Bailashui Sn deposit is a indicator of a later magmatism characterized by enrichment of mantle materiald in the depth of Qitianling intrusion. These metallogenic regularities in Nanling have indicating significance for W-Sn exploration in Tibet, i.e., to explore W-Sn mineralization in the depth of epi-mesothermal deposits in low erosion areas, and to explore the meso-hypothermal W-Sn deposits in the high erosion areas. Source

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