Abstract:Late Paleozoic post-collisional granitoid intrusions are extensively developed in West Junggar and even in the whole northern Xinjiang. The Kulumusu series of Kulumusu batholith in the Wuerkashier of West Junggar, which is one of these intrusions, mainly comprises monzogranite, fine-grained syenogranite, middle-coarse-grained syenogranite, alkali feldspar granite and K-feldspar porphyry. The Kulumusu series is characterized by high silica (SiO₂=70.78%～76.85%), alkali (K₂O+Na₂O=7.87%～9.71%), and low titanium and calcium (TiO₂=0.08%～0.41%, CaO=0.16%～1.42%), thus belonging to metaluminous to strongly peraluminous series (ACNK=0.98～1.15). The rocks display "V"-shaped REE patterns, and are evidently depleted in Eu. They are enriched in light rare earth elements (Rb, Th, K) and high strength field elements (Zr, Hf), and significantly depleted in Ba, Sr, P and Ti. These features indicate that the Kulumusu series belongs to A₂-type granite. In combination with the tectonic evolution of this region, the authors hold that the Kulumusu series was formed in a post-collisional tectonic setting.

Abstract:Lying in the north of Gandise-Nyainqentanglha magmatic arc, the Lietinggang deposit is a typical iron polymetallic deposit in the Gandise Pb-Zn-Ag-Cu-Fe metallogenic belt. Granodiorite and granite porphyry have a close metallogenic relationship with the Lietinggang deposit. The authors conducted LA-ICP-MS zircon dating of the granodiorite and granite porphyry, which yielded monzonitic granite age of 58.69±0.68 Ma and granite porphyry age of 60.69±0.98 Ma. The Lietinggang deposit was compared in metallogenic background with the ore deposits in Gandise-Nyainqentanglha magmatic arc, such as Jialapu, Sharang and Yaguila. With the underplating of mantle-derived magma during India-Eurasin continental collision, the series of deposits were formed in the main collision period. The zircon Lu-Hf of zircons from the Lietinggang deposit have εHf(t) values ranging from -3.01 to 3.0, and t_DM2 ages of Hf between 742 and 1 322 Ma, suggesting that the magma was from the mantle and the crust. The exploration achievements of the Lietinggang deposit show that the exploration of the iron polymetallic deposits in this region should be focused on the prospecting for Cu, Pb, Zn resources in the depth.

Abstract:The Xinxing lead-zinc (silver) deposit is located in the Tianbaoshan ore concentration area of Yanbian Prefecture, east part of the Xing'an-Mongolia Orogenic Belt. The major orebody is controlled by breccia pipe hosted by the granodiorite intrusion. In order to determine the petrogenetic and metallogenic ages, the material source and the tectonic setting of this deposit, the authors conducted LA-ICP-MS U-Th-Pb dating of zircon grains from the granodiorite related to the mineralization and made geochemical analysis of the intrusion. Zircon grains from granodiorite have the weighted average U-Pb age of 264.6±4.4 Ma(n=15), which means that the rock was emplaced in the middle Permian. The Xinxing granodiorite is characterized by high sodium (Na₂O/K₂O=1.36～1.85, avg.>1), metaluminous nature (A/CNK=0.96～1.04, avg.=0.99), and mid-high Al₂O₃(16.04%～16.34%), similar to features of the arc volcanic rocks, indicating that the metallogenic granodiorite belongs to I-type granite and the high potassium-calc-alkaline series. Most of the samples are strongly enriched in light rare earth elements (LREE)(La/Yb)_N=8.44～16.64, and have low negative Ce anomalies (δCe=0.72～0.91, avg.=0.83) as well as low positive Eu anomalies (δEu=1.00～1.15, avg.=1.06), with the enrichment of such large ion lithophlie elements (LILE) as Ba, Rb and K and incompatible trace elements of Th and U, and relative depletion of high field strength elements (HFSE) such as Ta, Nb and Ti. The ratios of trace elements are between the average value of the crust and that of the mantle, implying the contribution of crust-derived material. In combination with late Paleozoic tectonic evolution of Northeast China, the authors consider that the metallogenic event of granodiorite and related hydrothermal mineralization were caused by the subduction of the Paleo-Asian Ocean Plate in middle Permian. The identification of the magmatic-hydrothermal mineralization event in the area is of great significance for the study of regional mineralization and regional metallogenic regularity.

Abstract:The ophiolite in northeast Jiangxi is one of the most important Precambrian ophiolites in South China. Zircon U-Pb age and Hf isotope of a gabbro collected from Zhangshudun in the northeast Jiangxi ophiolite were studied for the purpose of constraining the timing and tectonic setting of the northeast Jiangxi ophiolite. LA-ICP-MS zircon U-Pb dating yielded a weighted mean ²⁰⁶Pb/²⁰⁷Pb age of 1 061±44 Ma for the Zhangshudun gabbro, indicating that the northeast Jiangxi ophiolite formed in late Mesoproterozoic. Zircon from the Zhangshudun gabbro exhibits a narrow range of initial Hf isotope ratios[εHf(t)=6.22～9.94], with corresponding t_DM1 of 1.21～1.41 Ga. The εHf(t) values are obviously lower than the value of depleted mantle reservoir (1 061 Ma) and the t_DM1 values are obviously older than the timing of zircon growth. Geochemistry and zircon Hf isotopic characteristics show that these gabbros are similar to gabbros of the typical E-MORB. These features, combined with previous research results, suggest that these rocks were mostly derived from low degree partial melting primitive mantle. It is held that the northeast Jiangxi ophiolite was formed in an initial mid-ocean ridge setting at the beginning stage of the oceanic basin spreading, and the northeast Jiangxi ophiolite is mainly MOR type ophiolite.

Abstract:Located about 120 km south of Hailar City in Hulun Buir League, the newly-discovered Honghuaerji scheelite deposit is the only scheelite deposit in central-northern section of Da Hinggan Mountains. The ore-bearing granites comprising monzogranites and quartz monzonite intruded into the Ordovician Luohe Formation (O_2-3lh). The LA-MC-ICP-MS zircon U-Pb dating results show that the reddish monzogranite was formed at 179.2±0.6 Ma (N=20, MSWD=1.3), the gray monzogranite was formed at 179.0±0.6 Ma (N=20, MSWD=0.7) and the quartz monzonite was formed at 178.6±0.7 Ma (N=20, MSWD=0.6). The high concordance of the dating results indicates that they were formed by magma activities in Early Jurassic. The inherited zircon (779.1 Ma and 463.2～486.0 Ma) has also been found in the three granites, which indicates that the Neoproterozoic and Lower-Middle Ordovician blocks are probably existent in the study area. The three granites have similar petrogeochemical characteristics. Geochemical analysis shows that all of the three rocks have high SiO₂ (63.09%～73.53%) and K₂O+Na₂O (7.60%～8.74%), and are slightly peraluminous (A/CNK=0.97～1.08). They are enriched in light rare earth elements and depleted in heavy rare earth elements [(La/Yb)_N=3.96～12.28] with a medium negative Eu anomaly (δEu=0.55～1.01). They are also enriched in Rb, Th, U, K, Pb and depleted in Ba, Nb, Ta, Sr, P, Ti. The analytical results of main and trace elements show that they are typical I-type granites. The ore-forming materials were mainly derived from the lower crust and also extracted from the tungsten-bearing formation by the magma.

Abstract:"Changshan-type"fluorite deposits are a new type of deposits discovered in the Qinzhou-Hangzhou metallogenic belt recently. A study of orebody characteristics shows that they are different from filling-metasomatic and stratabound type fluorite deposits in carbonate rocks in location of orebody and characteristics of ores. The orebodies discovered in the past are located on the southeast limb of Yanqian brachyanticline as well as the outer contact zone of Yanqian granite and Cambrian carbonates. The discovery of the Kumalin deposit in the hinge zone of anticline enriches the metallogenic theory of the "Changshan-type" fluorite deposits. The lithologic differences of Cambrian carbonates had no obvious relationship with mineralization. Filling is the main metallogenic mode, as shown by the CaF₂ content of immediate roof and floor. Studies show that the high-F magma that invaded in the late Yanshanian epoch was the most important factor for the formation of the deposit. The roof-fall structure in the outer contact zone of Yanqian granite and interformational tectonic zone seem to be the main ore-controlling structure. Based on the study of the geological characteristics and metallogenic regularity, the authors have summarized the genesis of the deposit, established the metallogenic model and provided the new train of thought for the same type of deposits in northwest Zhejiang and even the whole South China.

Abstract:Very low-grade metamorphic rocks are widely spread in the sedimentary basin. During the diagenetic to low-grade metamorphic process, the evolution stage of petroleum and coal would undergo corresponding changes with the increasing metamorphic grade. Thus, the very low-grade metamorphism has close relationship with oil, gas, coal and other energy mineral resources. This paper first summarizes some aspects of this problem and the new progress in the study of very low-grade metamorphism, such as the dividing of very low-grade metapelitic zones, geothermobarometry on clay minerals, metamorphic p-T-t path and their application to the sedimentary basin, and then preliminarily discusses the Triassic very low-grade metamorphism in the Zoigê depression, northwest Sichuan. Studies show that the research on diagenetic to very low-grade metamorphism in the sedimentary basin has great theoretical and practical significance in dividing the boundary between diagenesis and metamorphism, determining the stage of basin maturity, recovering the paleotemperature and paleotectonic history and, on such a basis, guiding oil and gas exploration.

Abstract:In-situ high pressure single-crystal X-ray diffraction investigation of dioptase was carried out at room temperature using diamond anvil cells (DAC) with synchrotron radiation source. No phase transition of dioptase was observed up to the highest pressure of 11.7 GPa. The results obtained from single-crystal X-ray diffraction between 10^-4 and 11.7 GPa reveal volume decreasing as a function of pressure, corresponding to K₀=114.6±5.3 GPa for the bulk modulus and K'=2.7±0.8 for its pressure derivative for a third-order Birch-Murnaghan equation of state. When pressure is lower than 9.3 GPa, c-axial compressibility is larger than that of a-axis; in the pressure range of 9.3～11.7 GPa, water molecules in the structure of dioptase will produce strong compression of rings of six silicate tetrahedra under high pressure, causing the reduction of c-axial compressibility, and eventually the degree of a-axis compression is nearly the same as that of c-axis at 11.7 GPa. By analyzing high pressure behavior of many aqueous annular silicate minerals, the authors have come to the conclusion that the form of water molecules plays a key role in the elasticity of aqueous annular silicate minerals.

Abstract:Source components and genesis of continental intraplate basalts are pivotal to understanding the chemical heterogeneities and geodynamic processes of the Earth's mantle. Since different mantle end members have different H₂O values and H₂O/incompatible element (such as H₂O/Ce) ratios, the H₂O content of primary basaltic magma might provide constraints on source components of continental intraplate basalts. Quenched glasses and melt inclusions in phenocrysts are commonly used to obtain the water content of primary magma of oceanic basalts, but they cannot provide useful information concerning the water content of primary magma for continental basalts. On the one hand, continental basaltic glasses usually experienced highly degassing when they were erupted at the surface due to the lack of water pressure to oceanic basalts, thus causing underestimation of the true water content. On the other hand, melt inclusions in phenocrysts in continental basalts are rare and very tiny (<20 μm), which hinders accurate analysis of large quantities of samples. This paper introduces a newly developed method for estimating the water content of primary magma of continental basalts. The H₂O values of clinopyroxene phenocrysts in basalts are determined by FTIR, and those of equilibrated melts are calculated through partition coefficients of H₂O between clinopyroxene and basaltic melt. When the effects from degassing, assimilation and fractional crystallization during magma ascent are evaluated, the H₂O content of primary magma of continental basalts can be estimated. The feasibility of the method, the evaluation of the uncertainty and the detailed operation procedure have been described. With this method, the H₂O content of the Cenozoic alkali basalts from Shuangliao of Northeast China and Taihang Mountain of NCC have been estimated. Combined with other geochemical index, these new data provide additional information on the source components of basalts.

Abstract:In this study, the authors investigated the electronic structures of Fe- and/ or Cd-doped sphalerite ZnS by first-principles calculations. Theoretical results show that the band gap of pure sphalerite is 2.85 eV. The results show that Fe-doped sphalerite ZnS with a doping amount of 3.125% has a band gap of 2.58 eV, and the hybridization of Fe 3d and S 3p orbital introduces two intermediate bands in the middle of the forbidden band. With the increase of the amount of Fe-doped, the width and peak height of intermediate bands also increase. The band gap of Cd-doped sphalerite is reduced to 2.68 eV, and the intermediate band below the bottom of the forbidden band is due to the hybridization of Cd 4d and S 2p orbital. Fe- and Cd-codoping reduces the band gap of sphalerite to 2.49 eV, and two donor levels in band gap can improve responding capability to visible light of sphalerite. These results provide theoretical supports for better understanding of photocatalytic mechanism of Fe- and Cd-doped natural sphalerite under visible light.

Abstract:In order to thoroughly understand the mechanism between microbe and atmospheric inhaled mineral fine particles, the authors used calcite (PM_2.5) as the research object, and made qualitative and quantitative analysis of the main components of Silicate bacteria, Staphylococcus aureus and Escherichia coli extracellular organic acids by reverse phase high performance liquid chromatography (RP-HPLC). On such a basis, the authors investigated the dissolution of calcite by bacterial organic acids. The results are as follows: The main organic acids components of three common bacteria include oxalic acid, lactic acid, citric acid and succinic acid; Different organic acids have different effects on dissolution of calcite: ① Serveral different organic acids can promote the release of Ca ions at different levels; ② Calcite exhibits the weight of grain decrease under the action of oxalic acid, lactic acid and citric acid, whereas recrystallization occurs under the action of citric acid, which aslo can change the surface morphology of calcite, making the residue exhibit fibrous form; ③ Under the action of oxalic acid and citric acid, the residue absorbs the organic acid groups (e.g. C=O, C—C or C—H), especially in the region 1 600～500 cm^-1 in citric acid.

Abstract:In order to reveal the paleoclimate evolution of the Oligocene-Miocene sediments in the Gerze Basin, Tibet, the authors used X-Ray diffraction (XRD) to analyze the Mineral assemblage characteristics in combination with the sedimentary environments and sedimentary facies of Gerze Basin. The results show that the main minerals in the sediments are quartz, feldspar and calcite, with small amounts of dolomite, and their relative content varies along the section. Variations of relative values and ratios of quartz/feldspar suggest that the Gerze Basin has experienced four-stage paleoclimatic evolution: Stage Ⅰ(early Oligocene), characterized by high quartz and carbonate mineral content and low feldspar content; dolomite occurred frequently at this stage, and the content changed significantly, indicative of a dominant seasonal arid climate; Stage Ⅱ(late Oligocene), characterized by high quartz content, which, however somewhat decreased, indicating a colder and drier climate; Stage Ⅲ(early Miocene), characterized by high quartz content; nevertheless, compared with features of the previous two stages, the quartz content further decreased, the content of feldspar further increased, and carbonate tended to become an overall increase. Compared with the previous two stages, dolomite increased significantly whereas quartz/feldspar ratios decreased, indicating that the climate became colder and drier; Stage Ⅳ(mid-Miocene), during which quartz content relatively increased, feldspar and carbonate minerals content decreased, quartz/feldspar ratios also increased; nevertheless, compared with Stage Ⅰ and Ⅱ, the quartz/feldspar ratios remained small, indicating that the climate was somewhat recovered, but still in a cold and dry environment. Compared with the uplift of the Tibetan Plateau and the global climate change, the authors hold that that climatic periodic changes during Oligocene-Miocene in the Gerze Basin might have been caused by plateau uplift and the global climate change.

Abstract:Lying in a distinctive tectonic locality within the collisional belt between the India and Eurasian plates, the Myanmar jadeitites deposit is one of the largest and most important jadeite deposits in the world. It has been shown that the Myanmar jadeitites formed during the subduction of the Neo-Tethys oceanic crust when peridotites experienced high-pressure metamorphism and metasomatism. In this paper, a fluid inclusion study of the Myanmar jadeitite samples with variable deformation degrees was carried out and, as a result, four types of fluid inclusions were identified: ① low-salinity aqueous inclusions with or without minor CH₄ (type Ⅰ), the primary type Ⅰ inclusions occur either as isolated ones or in clusters in the core or along the growth zones of jadeite crystals with primary growth textures; ② three-phase H₂O±CH₄ inclusions with halite daughter crystals (type Ⅱ); ③ pure CH4 inclusions which can be subdivided into high-density ones (type Ⅲa) and low-density ones (Ⅲb); ④ gaseous or empty inclusions (type Ⅳ). This investigation revealed that several fluid events occurred during the formation and evolution of Myanmar jadeitites and related rocks. A fluid phase that originated probably from sea water should have been present during the formation of jadeitite in the high-pressure metamorphic-metasomatic process of peridotite; the high-salinity aqueous inclusions and high-density CH₄ inclusions were recognized for the first time in the Myanmar jadeitites, the high-salinity aqueous fluid was probably related to the recrystallization process of the jadeidite, and the preserved high-density CH₄ in the jadeitite was probably generated as a by-product of serpentinization of ultramafic rocks in the mantle wedge above the subducting slab, coupled with the complete consumption of water during hydration of serpentine. The calculated fluid inclusion isochores suggest that various degrees of reequlibration of these fluid inclusion occurred during the evoluition of the jadeitites.

Abstract:Guilin Chicken Blood Red Jasper (CBRJ) is a kind of quartz jasper. It is characterized by bright red to black colors and high hardness. However, few researches have been focused on the field occurrence, geological background, rock structure and genesis of its color. Field surveys indicate that the Guilin CBRJ is hosted in low-grade metamorphic sandstones which experienced vapor-water hydrothermal metamorphism and iron oxide dissemination. It occurs in the Sanmenjie Formation of Neoproterozoic Danzhou Group in Longsheng area in the north of Guangxi. Tectonically, the ore deposit of Guilin CBRJ is located at the juncture of Yangtze and Cathaysian plates, which has undergone a complex geological process. Its formation was related to multi-phase tectono-magmatic activities from Neoproterozoic to Triassic. Detailed analyses of mineralogy, micro-texture and geochemical composition of Guilin CBRJ were carried out by polarizing microscope, X-ray diffraction, and electronic microprobe. The results indicate that the CBRJ is mainly composed of quartz and hematite, with dolomites in some samples. Quartz grains exhibit two types of allotriomorphic equigranular texture and idiomorphic porphyroblastic texture. The latter one, in which distinct enlargement texture can be observed, reveals a metasomatic metamorphism phase. Hematite occurs in three types: ① single crystal existent between or inside the quartz particles, ② dusty crystals wrapped in the quartz particles, and ③ disseminated crystals filled between the quartz particles. The Fe³⁺ in the hematite should be responsible for the color of the CBRJ. Electron microprobe analysis shows that the hematites of single crystal and disseminated crystals have 78.9%～85.6% iron oxides, but the dusty crystal is too small to be analyzed. In combination with the different generations of quartz and hematite, the authors have reached the conclusion that the formation of different types of these minerals in the Guilin CBRJ was consistent with the regionally geological evolution in this area.

Abstract:Based on the compilation of 30 cases around the world, the author holds that the so-called "Guangxi-type granite" does not contain the petrological and geodynamic significance as argued by Zhang Qi (2014), who has proposed the nomenclature. The Sr and Yb enriched "Guangxi-type granites" are composed of intermediate to acid and peralkaline rocks in lithology, and most of them exhibit negative Eu anomalies. From the perspective of rock association (series), the so-called "Guangxi-type granite" is actually the mingling of calc-alkaline, alkaline, and A-type granite. In fact, the "Guangxi-type granite" can be generated by many petrogenetic mechanisms, including the fractional crystallization or assimilated fractional crystallization (AFC) of mafic magma, and the partial melting of crustal sources, with the plagioclase as one of the crystallization or residual phases. The comparison of the phase diagrams from fluid-absent melting of common crustal source rocks shows that the whole-rock Sr and Yb content of granitic rocks cannot be regard as a reliable index to indicate the melting pressure of granitic magma. Accordingly, the "Sr-Yb" classification of granitic rocks proposed by Zhang Qi is useless for geodynamic study.

Abstract:Wang Yang wrote a critique arguing that "Guangxi-type granite" does not contain the petrological and geodynamic significance, the whole-rock Sr and Yb content of granitic rocks cannot be regard as a reliable index to indicate the melting pressure of granitic magma, and the "Sr-Yb" classification of granitic rocks is useless for geodynamic study. The author indicates that granites were formed under different pressures, like adakites and arc magmatic rocks (andesite-dacite-rhyolite). Wang Yang thinks that granitic magma can be formed either in the lower crust or in the middle crust, and also believes that granitic magma can be formed by basic magma fractional crystallization. Because of the lack of field evidence, the author does not agree with these arguments. The Sr and Yb enriched Guangxi-type granites indicates that there is no garnet and plagioclase in residual phases. Wang Yang quotes different opinions from different scholars, but these opinions have nothing to do with the concept of the Guangxi-type granites proposed by the author. Therefore, Wang Yang fails to deny the author's understanding concerning Guangxi-type granite based on his arguments.