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In-situ LA-ICP-MS analysis and S isotopes of pyrite from the Baoshan Cu polymetallic deposit were conducted to investigate the ore-forming process and the enrichment mechanism of elements. Three generations of pyrite (Py I, Py II, and Py III) in the skarn-type ores and pyrite in the carbonate-hosted sulphide ores from central, western, and northern (C_Py, W_Py, and N_Py) mining districts are selected for comparison. Compared with Py I and Py III, the contents of most elements in Py II are apparently higher. The As and Se contents are high within a wide range and are decoupled in the growth band of the C_Py. The highest As, Se, and Pb contents were found in W_Py and N_Py. These results indicate the drastic changes in the temperature and fluid mixing during the mineralisation. The occurrence of fluctuation and change in temperature and f(O2) was triggered by intermittent pulses of magmatic-hydrothermal fluids, mixing with meteoric water, and water−rock interactions. The sulphur isotopes of all species of pyrite indicated the magmatic source. The change in the f(O2) conditions caused slight differences in the S isotope compositions. Consequently, a metallogenic model was proposed to explain the ore-forming processes., In-situ LA-ICP-MS analysis and S isotopes of pyrite from the Baoshan Cu polymetallic deposit were conducted to investigate the ore-forming process and the enrichment mechanism of elements. Three generations of pyrite (Py I, Py II, and Py III) in the skarn-type ores and pyrite in the carbonate-hosted sulphide ores from central, western, and northern (C_Py, W_Py, and N_Py) mining districts are selected for comparison. Compared with Py I and Py III, the contents of most elements in Py II are apparently higher. The As and Se contents are high within a wide range and are decoupled in the growth band of the C_Py. The highest As, Se, and Pb contents were found in W_Py and N_Py. These results indicate the drastic changes in the temperature and fluid mixing during the mineralisation. The occurrence of fluctuation and change in temperature and f(O2) was triggered by intermittent pulses of magmatic-hydrothermal fluids, mixing with meteoric water, and water−rock interactions. The sulphur isotopes of all species of pyrite indicated the magmatic source. The change in the f(O2) conditions caused slight differences in the S isotope compositions. Consequently, a metallogenic model was proposed to explain the ore-forming processes.

The Xiangdong W(-Sn) deposit is hosted in the Dengfuxian multiphase granites (biotite, two-mica, and muscovite granites) within the Nanling Range metallogenic belt. Previous studies suggested that the W(-Sn) mineralisation in the Xiangdong deposit is related to the Late Jurassic two-mica granite, whereas recently W-Sn–bearing quartz veins have also been identified in muscovite granite. New cassiterite and zircon U-Pb ages are presented to constrain the timing of W-Sn mineralisation and related granitic magmatism. LA-ICP-MS U-Pb dating of zircon grains, combined with previous zircon ages, in addition to the trace element composition of the muscovite granite, suggest the muscovite granite in the Dengfuxian pluton was emplaced at 145 to 142 Ma and shows highly evolved features. Cassiterite grains from the ore-bearing veins in two-mica granite yielded U-Pb ages of 151.6 ± 3.7 and 141 to 138 Ma, whereas cassiterite grains from quartz veins occurring in muscovite granite yielded a U-Pb age of 136.8 ± 3.3 Ma. The new ages and detailed geologic evidence indicate that the Early Cretaceous muscovite granite is also genetically related to W-Sn mineralisation. Combining this with previously published data from the Late Jurassic two-mica granites and related mineralisation, it is suggested that there were two stages of W-Sn mineralisation at Xiangdong. Arsenopyrite geothermometry from the two stages suggests temperatures of 300-491 degrees C and 308-450 degrees C in stage I and stage II, respectively. Wolframite grains from the two stages also show different characteristics and patterns for their major and trace elements. The Early Cretaceous muscovite granite is an important new target for W and Sn resources in South China., The Xiangdong W(-Sn) deposit is hosted in the Dengfuxian multiphase granites (biotite, two-mica, and muscovite granites) within the Nanling Range metallogenic belt. Previous studies suggested that the W(-Sn) mineralisation in the Xiangdong deposit is related to the Late Jurassic two-mica granite, whereas recently W-Sn–bearing quartz veins have also been identified in muscovite granite. New cassiterite and zircon U-Pb ages are presented to constrain the timing of W-Sn mineralisation and related granitic magmatism. LA-ICP-MS U-Pb dating of zircon grains, combined with previous zircon ages, in addition to the trace element composition of the muscovite granite, suggest the muscovite granite in the Dengfuxian pluton was emplaced at 145 to 142 Ma and shows highly evolved features. Cassiterite grains from the ore-bearing veins in two-mica granite yielded U-Pb ages of 151.6 ± 3.7 and 141 to 138 Ma, whereas cassiterite grains from quartz veins occurring in muscovite granite yielded a U-Pb age of 136.8 ± 3.3 Ma. The new ages and detailed geologic evidence indicate that the Early Cretaceous muscovite granite is also genetically related to W-Sn mineralisation. Combining this with previously published data from the Late Jurassic two-mica granites and related mineralisation, it is suggested that there were two stages of W-Sn mineralisation at Xiangdong. Arsenopyrite geothermometry from the two stages suggests temperatures of 300-491 degrees C and 308-450 degrees C in stage I and stage II, respectively. Wolframite grains from the two stages also show different characteristics and patterns for their major and trace elements. The Early Cretaceous muscovite granite is an important new target for W and Sn resources in South China.

The Pingtan deposit, situated in the Northwest part of the Miao’ershan granite batholith (western Nanling Range), is a newly-discovered Caledonian W-(Mo) deposit. Its mineralisation can be divided into two stages, namely quartz-scheelite stage (I) and quartz-sulphide stage (II). The homogenisation temperatures (260-380 degrees C for Stage I and 240-300 degrees C for Stage II) and the average salinities (11.26% NaCl equiv. for Stage I and 8.61% NaCl equiv. for Stage II) show significant decreasing trends from early to late. Raman spectroscopy reveals that the fluid inclusions in stage I contain CO2, CH4, and N2, whilst those in stage II mainly contain H2O. A proportion of daughter mineral-bearing inclusions discovered in quartz veins of stage I and the sulphur isotopes from sulphides (-0.00 49 to +0.002 06, average +0.000 5) imply that the ore-forming fluid is originated from magmatic fluids. Therefore it can be concluded that the ore-forming material in the Pingtan deposit is derived from partial melting of crust which experiences high fractionation, and the effective metallogenic mechanism of the deposit might be fluid boiling., The Pingtan deposit, situated in the Northwest part of the Miao’ershan granite batholith (western Nanling Range), is a newly-discovered Caledonian W-(Mo) deposit. Its mineralisation can be divided into two stages, namely quartz-scheelite stage (I) and quartz-sulphide stage (II). The homogenisation temperatures (260-380 degrees C for Stage I and 240-300 degrees C for Stage II) and the average salinities (11.26% NaCl equiv. for Stage I and 8.61% NaCl equiv. for Stage II) show significant decreasing trends from early to late. Raman spectroscopy reveals that the fluid inclusions in stage I contain CO2, CH4, and N2, whilst those in stage II mainly contain H2O. A proportion of daughter mineral-bearing inclusions discovered in quartz veins of stage I and the sulphur isotopes from sulphides (-0.00 49 to +0.002 06, average +0.000 5) imply that the ore-forming fluid is originated from magmatic fluids. Therefore it can be concluded that the ore-forming material in the Pingtan deposit is derived from partial melting of crust which experiences high fractionation, and the effective metallogenic mechanism of the deposit might be fluid boiling.

Mesozoic tectonic-magmatism events with a wide range of magma and a large number of deposits strongly occur in the Qin-Hang metallogenic belt (QHMB) within the South China Plate, which is significant for further insight into the geological evolution in the South China Plate. The whole rock geochemical data, zircon U, Pb and Hf isotopes of Baishifeng stock in the Dangjiachong Cu deposit were determined, within the middle part of the QHMB. The lithology of the Baishifeng granitic samples are biotite adamellite, enriched in Si (w(SiO2)=70.95-72.12%), alkali (w(Na2O+K2O)=8.48-8.99%), weakly peraluminous (A/CNK=1.07-1.09) and have zircon saturation temperature ranging from 658 to 816 degrees C, which are identical with the features of the I-type granite. LA-ICP-MS zircon dating of Baishifeng granite samples yield an age of (135.4±0.8) Ma (MSWD=1.9, N=14), i.e., Early Cretaceous. The lower Mg values (35-38), Co (3×10-6-4×10-6), Ni (3×10-6-5×10-6), Sr (111×10-6-131×10-6) and Yb (1.13×10-6-1.36×10-6) contents, the weakly negative Eu anomalies, lower Nb/Ta ratios, depletion of Hf isotopes and Hf model ages of 1 484-1 228 Ma indicate that the Baishifeng granitic body is derived from partial melting of the Mesoproterozoic rocks containing garnets and plagioclase. In conjunction with previous studies, the Baishifeng granitic body is formed under a transition environment from squash to stretch, which is associated with transition from subduction to rollback of the Pacific Ocean., Mesozoic tectonic-magmatism events with a wide range of magma and a large number of deposits strongly occur in the Qin-Hang metallogenic belt (QHMB) within the South China Plate, which is significant for further insight into the geological evolution in the South China Plate. The whole rock geochemical data, zircon U, Pb and Hf isotopes of Baishifeng stock in the Dangjiachong Cu deposit were determined, within the middle part of the QHMB. The lithology of the Baishifeng granitic samples are biotite adamellite, enriched in Si (w(SiO2)=70.95-72.12%), alkali (w(Na2O+K2O)=8.48-8.99%), weakly peraluminous (A/CNK=1.07-1.09) and have zircon saturation temperature ranging from 658 to 816 degrees C, which are identical with the features of the I-type granite. LA-ICP-MS zircon dating of Baishifeng granite samples yield an age of (135.4±0.8) Ma (MSWD=1.9, N=14), i.e., Early Cretaceous. The lower Mg values (35-38), Co (3×10-6-4×10-6), Ni (3×10-6-5×10-6), Sr (111×10-6-131×10-6) and Yb (1.13×10-6-1.36×10-6) contents, the weakly negative Eu anomalies, lower Nb/Ta ratios, depletion of Hf isotopes and Hf model ages of 1 484-1 228 Ma indicate that the Baishifeng granitic body is derived from partial melting of the Mesoproterozoic rocks containing garnets and plagioclase. In conjunction with previous studies, the Baishifeng granitic body is formed under a transition environment from squash to stretch, which is associated with transition from subduction to rollback of the Pacific Ocean.

The Shizitou Mo deposit in Yongping is a recently discovered important deposit in the eastern section of the Qin-Hang metallogenic belt. The Mo deposit mainly occurs in the outer contact zone between the porphyry biotite granite and the Zhoutan group migmatite, and is mainly controlled by the rock body and structures. Re-Os dating of molybdenite gives a model age of 156.9±2.2 to 158.5±2.4 Ma, with a weighted mean age of 158±1 Ma, and gives an isochron age of 158.0±2.5)Ma. The Re content of the molybdenite is 65.05×10(-6) to 150.20×10(-6), indicating that the ore-forming materials have mantle-crust mixed features. Based on the comparison between the ore-forming age and the rock-forming age of the deposit area, and by looking into the geological features and geochemical features of the deposit, it is concluded that the ore-forming process of the area was closely linked with the porphyry biotite granite rock body, and that both the deposit and the rock body are products of the same geological-tectonic-magmatic event under the same dynamic background. Based on previous studies it is believed that two episodes of Mo ore-forming events at 172-145 Ma and 140-130 Ma have occurred in the NE section of the Qinhang metallogenic belt. The time of the two episodes corresponds with the two ore-forming peak periods in late Jurassic and Cretaceous, in response to the back-arc partial extension associated with the low-angle subduction of the Izanagi plate beneath the Eurasia plate and the quick NE-striking slipping of the Izanagi subduction plate., The Shizitou Mo deposit in Yongping is a recently discovered important deposit in the eastern section of the Qin-Hang metallogenic belt. The Mo deposit mainly occurs in the outer contact zone between the porphyry biotite granite and the Zhoutan group migmatite, and is mainly controlled by the rock body and structures. Re-Os dating of molybdenite gives a model age of 156.9±2.2 to 158.5±2.4 Ma, with a weighted mean age of 158±1 Ma, and gives an isochron age of 158.0±2.5)Ma. The Re content of the molybdenite is 65.05×10(-6) to 150.20×10(-6), indicating that the ore-forming materials have mantle-crust mixed features. Based on the comparison between the ore-forming age and the rock-forming age of the deposit area, and by looking into the geological features and geochemical features of the deposit, it is concluded that the ore-forming process of the area was closely linked with the porphyry biotite granite rock body, and that both the deposit and the rock body are products of the same geological-tectonic-magmatic event under the same dynamic background. Based on previous studies it is believed that two episodes of Mo ore-forming events at 172-145 Ma and 140-130 Ma have occurred in the NE section of the Qinhang metallogenic belt. The time of the two episodes corresponds with the two ore-forming peak periods in late Jurassic and Cretaceous, in response to the back-arc partial extension associated with the low-angle subduction of the Izanagi plate beneath the Eurasia plate and the quick NE-striking slipping of the Izanagi subduction plate.

Ore-vein intercalation and mineral-association studies indicate that mineralisation in the Liba gold deposit, Gansu province, China comprises a hydrothermal stage consisting of pyrite, beresite and polymetallic phases, and an exogenous stage. Component and gold-distribution-state analyses of metal sulphides - pyrite, arsenopyrite and sphalerite - of the three phases using electron probe microanalysis show a w(Co)/w(Ni) ratio of 0.15-4.50 for pyrite and an FeS molecular content of 18.81-22.97% for sphalerite, indicative of the deposit forming in a medium-high-temperature environment. The results of gold-content determinations, arsenic-gold relationship diagrams and distribution analyses of elemental gold in metal sulphides suggest that pyrite and arsenopyrite are the principal gold-bearing minerals in the deposit and that the occurrence of micro- and sub-micro native gold inclusions is dominant in these two minerals. The geological and component characteristics of the metal sulphides indicate that Liba may be considered as a medium-high-temperature and medium-deep hydrothermal gold deposit (closely related to Zhongchuan)., Ore-vein intercalation and mineral-association studies indicate that mineralisation in the Liba gold deposit, Gansu province, China comprises a hydrothermal stage consisting of pyrite, beresite and polymetallic phases, and an exogenous stage. Component and gold-distribution-state analyses of metal sulphides - pyrite, arsenopyrite and sphalerite - of the three phases using electron probe microanalysis show a w(Co)/w(Ni) ratio of 0.15-4.50 for pyrite and an FeS molecular content of 18.81-22.97% for sphalerite, indicative of the deposit forming in a medium-high-temperature environment. The results of gold-content determinations, arsenic-gold relationship diagrams and distribution analyses of elemental gold in metal sulphides suggest that pyrite and arsenopyrite are the principal gold-bearing minerals in the deposit and that the occurrence of micro- and sub-micro native gold inclusions is dominant in these two minerals. The geological and component characteristics of the metal sulphides indicate that Liba may be considered as a medium-high-temperature and medium-deep hydrothermal gold deposit (closely related to Zhongchuan).