Abstract:The formation age of basalts from the lowermost Neoproterozoic Chengjiang Formation in the western Yangtze Block has not been determined yet. In this paper, field investigations and detailed petrologic and geochronologic researches were carried out on basalts of the lowermost Chengjiang Formation from the Luoci area, Wuding, and the results show that the formation age of basalts from the lowermost Chengjiang Formation is 804±6 Ma, which further confirms that the lower age limit of the Chengjiang Formation should be about 800 Ma. Petrologic studies show that basalts from the lowermost Chengjiang Formation have lower SiO₂ content and high K₂O+Na₂O and TiO₂ content, which indicates that their formation should be attributed to alkaline basalts developed in the continental rift. Combined with regional relevant research data, it is suggested that there possibly existed an episodic bimodal magmatic rock belt that lasted from ～800 Ma to 725 Ma along the western Yangtze Block. It is thus held that basalts of the Chengjiang Formation as well as volcanic rocks of the Suxiong Formation were formed by ~800 Ma bimodal magmatic activity, and that this bimodal magmatic rock belt might have been developed in the continental rift. Moreover, the ages of captured zircons from the basalts indicate that there were multi-stage regional tectonic-thermal events along the western Yangtze Block, which took place at 2.5 Ga, 1.8～1.6 Ga and 1.0 Ga.

Abstract:The LA-ICP-MS zircon U-Pb ages and Hf isotopic data, major and trace elements and Sr-Nd-Pb isotopic compositions are presented in this paper for the Jiashan syenite intrusive on the northern margin of the North China Craton. The Jiashan syenite intrusive was emplaced at 111～108 Ma in the Early Cretaceous period. The pluton has high SiO₂, K₂O+Na₂O, Al₂O₃, LILEs (Rb, K) and LREE but low Fe₂O₃^T, CaO, TiO₂, MgO and HFSE, with no Nb and Ta anomalies, suggesting intracontinental rift volcanic rocks that belong to the A-type granite. εNd(t) = -5.0～-0.9, t_DM2(Nd)=0.98～1.31 Ga, εHf(t)=-2.7～+4.3, t_DM2(Hf)=0.90～1.33 Ga, Δ8/4=84.9～91.3, Δ7/4=-6.4～-4.0, (²⁰⁶Pb/²⁰⁴Pb)_i=16.63～17.10, (²⁰⁷Pb/²⁰⁴Pb)_i=15.24～15.30, and (²⁰⁸Pb/²⁰⁴Pb)_i=36.54～37.20. According to the comprehensive analysis of the geological field observation, experimental petrology, trace element geochemistry and Sr-Nd-Pb-Hf isotopes, the authors hold that the Jiashan pluton was derived from the mixed source of the lower crust and the depleted mantle, and resulted from the crustal extension and the lithosphere thinning of the NCC. The involvement of the depleted mantle during the formation of the Early Cretaceous Jiashan syenite intrusive indicates the lithospheric thinning on the northern margin of the North China Craton and the upwelling of the asthenosphere mantle, which recorded the magmatic events related to the asthenosphere underplating in a continental extensional environment.

Abstract:Located in the northeast of Jiangxi Province along the Qinzhou-Hangzhou junction belt, the Yaoli granite intruded into the Shuangqiaoshan rock group and Xikou rock group. The granite is mainly composed of quartz, potash feldspar, plagioclase, biotite and minor muscovite. The LA-ICP-MS zircon U-Pb dating shows that the one-forming age of the Yaoli pluton is 132.0±1.9 Ma, with another age of 141.7±2.6 Ma, suggesting that another magmatic activity occurred at 141.7±2.6 Ma. The Yaoli pluton is characterized by high K₂O/Na₂O ratios and SiO₂ content as well as low content of Al₂O₃, MgO, CaO and TiO₂. The A/CNK ratios vary from 0.92 to 1.17, mostly higher than 1.1, implying that the Yaoli granite belongs to high-K calc-alkaline and peraluminous series.The Yaoli granite is also enriched in LILEs but depleted in HFSEs of Nb and Ti.The δEu values vary from 0.30 to 0.86. The granite is remarkably characterized by enrichment of LREE, which is similar to things of Ehu pluton and Wolonggu pluton which were formed at the same time as the Yaoli granite.They were all generated by partial melting of metamorphosed argillaceous rock in the deep crust;nevertheless,the Yaoli granite is different from Tongchang granite,which formed in Middle Jurassic.These data show the decrease of formation temperature and pressure of the granite from Middle Jurassic to Early Cretaceous, suggesting that the tectonic setting of the northeast of Jiangxi Province along the Qinzhou-Hangzhou junction belt was an extensional tectonic environment.

Abstract:The discovery of the Xiongcun ore district is an important ore-prospecting breakthrough for Jurassic mineralization in the southern Gangdise metallogenic belt, Tibet. The No. Ⅰ, No. Ⅱ and No. Ⅲ copper-gold deposits were discovered in the Xiongcun ore district. In order to find out the relationship between porphyry mineralogical characteristics and the mineralization,the authors chose the ore-bearing porphyry of No. Ⅰ deposit as the research object. According to the modes of occurrence and electron microprobe data, biotite, muscovite, andalusite and rutile are products of hydrothermal alteration, whereas the orthoclase is mostly of hydrothermal origin with less magmatic origin. Such characteristics as abundant hypogene pyrrhotite, no anhydrite crystal, predominant ilmenite over magnetite, apatite with low SO₃ content (≤0.03%) and a large amount of methane in the ore-forming fluid indicate that the oxygen fugacity of the magmatic-fluid is low and the No. Ⅰ deposit of Xiongcun may be a reductive porphyry copper deposit. Temperatures measured by Zr-in-rutile thermometer are 622～762℃, which reflect the crystallization temperature of rutile and the middle-late stage temperature of potassic alteration. The larger grain sizes and relative enrichment of V₂O₅ (averaging 0.42%) in rutile and higher Mg, K and F with lower Ca in biotite are indicative of high-grade copper mineralization.

Abstract:Lots of late Early Carboniferous to Middle Permian acid-intermediate intrusive bodies are outcropped on the northern margin of the North China Craton. Because of rare exposure of the contemporaneous mantle-derived basic-ultrabasic rocks, it is very difficult to obtain some information concerning the mantle compositions and processes in this area. For the better understanding of the nature of the source rock, the authors chose the representative intrusions, i.e., Gushanzi ultrabasic rocks, which are about one hundred kilometers away from the southern Inner Mongolian Axis, for zircon U-Pb dating as well as trace element and Lu-Hf isotope analyzing. The LA-ICP-MS zircon U-Pb age of Gushanzi ultrabasic intrusion is 296.9±2.6 Ma, which indicates an Early Permian magma activity. The analytical results show the characteristics of low content of trace elements, strong positive Ce anomalies, slight negative Eu anomalies and relatively low εHf(t) values of -1.9～-7.5 (n= 17) in the sample Gushanzi-B3, indicating the source of enriched lithosphere mantle. Both t_DM and t_DM^C are higher than the U-Pb age, implying that the source rock was contaminated by ancient crust during its formation. Compared with zircon εHf(t) (-17.0～-14.1) values of Boluonuo hornblende-bearing gabbro in the Inner Mongolian Axis whose rock-forming age is 297±1 Ma, zircon εHf(t) values of Gushanzi ultrabasic rocks are obviously higher, implying a less enriched origin of Gushanzi ultrabasic rocks. Additionally, zircon εHf(t) of the other two testing plots of Gushanzi ultrabasic rocks are 3.2 and 4.0, respectively, which implies that a small amount of depleted mantle-derived substance was added to the primitive magma. The authors thus infer the existence of a local tensional and thinning setting of northern margin of North China Craton during Late Paleozoic.

Abstract:The Middle Cambrian gypsum-salt rocks are widely distributed in the Bachu Uplift of the Tarim Basin. These rocks are good regional cap rocks. Fluid inclusion petrography, microthermometry and thermodynamic calculation were used to study the halite samples from well Bt5. According to the analysis of fluid inclusion petrography, the primary fluid inclusion assemblages were preserved during the alteration of tectonic movement and bury process. An average homogenization temperature of 29.9℃ was yielded, which is consistent with the paleo-temperature of surface water. According to the result of thermodynamic calculation, the increasing rate of internal pressure of the fluid inclusions in halite was low during the bury process and it was probably one of the important factors responsible for fluid inclusion preservation.

Abstract:This paper describes the research status of constitutional water in nominally anhydrous pyroxene group minerals, especially the FTIR characterization and content of constitutional water of jadeite in different rocks. The jadeite minerals from Myanmar were investigated by using micro-FTIR and electron microprobe analysis (EPMA), and the constitutional water characterization of jadeite minerals from Myanmar was studied microcosmically. According to the results achieved, the constitutional water of jadeite minerals from Myanmar is characterized by spectral peaks in the range of 3 610～3 620 cm^-1 and 3 540～3 550 cm^-1 on the infrared spectra, the content of constitutional water of jadeite minerals in loose structure jade is higher on the outer side and less in the middle, and the constitutional water content in various parts of jadeite minerals with compact structure is fairly homogeneous. Content difference and change trend of constitutional water are not affected by its chemical composition, and probably result from such factors as fluid involvement in diagenesis, jade forming stage and plate subduction and exhumation process. The results achieved by the authors provide a certain basis for the genetic study of Myanmese jade.

Abstract:In this study, the adsorptive and reductive mechanisms for decolorization of orange-colored G (OG) by Fe(Ⅱ)/goethite interfacial complex system were systematically investigated. The examined focuses were placed on the effects of pH values, and molar ratios of Fe(Ⅱ)/OG on the OG decolorization. The results show that surface-bonded Fe(Ⅱ) on goethite can effectively improve the rate of reductive decolorization. The reactions over the Fe(Ⅱ)/goethite complex system can be described well by the pseudo first-order kinetics. The increases in the solution pH and the capacity of absorbed Fe(Ⅱ) enhance the reaction rate of OG removal. Moreover, OG removal efficiency can reach 100% within 1 h in the presence of Fe(Ⅱ)/goethite complex system under basic medium condition where the Fe(Ⅱ) /OG ratio is 27.0 and the OG initial concentration is 50 mg/L. The efficient removal of OG is resultant from the synergistic effect of adsorption and reduction. The results achieved by the authors provide the theoretical guidance for pollution remediation in an anaerobic environment by effectively using the Fe(Ⅱ)/goethite complex system.

Abstract:Emerald from Malipo in Yunnan Province was studied in this paper by using electron probe microanalyzer (EPMA), XRD and other technologies and, on such a basis, the characteristic features of Malipo emerald have been established: it contains two sets of trace elements (femic and alkali); the content of V₂O₃ is significantly higher than that of Cr₂O₃, which shows that V is the main element causing color; the refractive indices are No=1.584～1.586, Ne=1.576～1.579, and the specific gravity is 2.70±0.01; the isomorphous substitutions of Malipo emerald are of "octahedral-type". The mineralogical characteristics of Malipo emerald can be used to determine the origin of the emerald.

Abstract:Copper Company of Baiyin Nonferrous Group Co., Ltd. has produced about 1×10⁵ m³/a waste acid, in which the rhenium content is 5～70 mg/L. In this study, sodium thiosulfate was used as a special kind of good effect precipitant for extracting rhenium from waste acid. Through experimental studies of the mechanism of redox reaction, dosage, reaction time, reaction temperature and the influence of rhenium content on the precipitation rate of rhenium, the authors determined the optimum precipitation conditions. The pilot test achieved good technical indexes: the content of rhenium in rhenium-rich slag reached 1.66%, and the recovery rate of rhenium reached 99.8%. On such a basis, the mechanism of redox reaction of the precipitation agent was discussed. The precipitation method of sodium thiosulfate has the advantages of simple process, high rate of rhenium deposition and friendly environment, and it can therefore be used for efficient extraction of rhenium from waste acid.

Abstract:This paper presents a collection of 31 new uranium minerals approved by the Commission on New Minerals, Nomenclature and Classification (CNMMN) of the International Mineralogical Association (IMA) between January 2003 and December 2013. It lists the mineral names both in English and Chinese together with their structural formulae, crystal structure data, physical and optical properties, localities and modes of occurrence. The crystallochemical classification and characteristics of these new minerals are discussed. Some suggestions are put forward concerning China's uranium minerals research work in the hope of providing valuable reference for China's uranium researchers.