Abstract:Located in the junction part of the Jinshajiang suture zone and the Ganzi-Litang suture zone, the Yushu melange is a key area to reveal the Paleo-Tethyan tectonics of the northern central Tibetan Plateau. This study presents new geochemical data for the Xiewu basalts of the Yushu melange. These rocks have preserved a record of island arc magmatism on the northern margin of the North Qiangtang block. The basalts belong to calc-alkaline affinities. They are relatively enriched in large-ion lithophile elements and slightly depleted in high field strength elements. Their high MgO, Ni, and Cr values, relatively high La/Sm and low Sm/Yb ratios and positive bulk εNd(t) values suggest that they were derived from the partial melting of a depleted spinel-lherzolite mantle source metasomatized by hydrous fluids. The Xiewu basalts are geochemically similar to island arc basalts. Their eruption was related to initial subduction of the Ganzi-Litang Paleo-Tethyan oceanic plate beneath the North Qiangtang block. Combined with existing data, the authors hold that the Yushu melange converged with the Ganzi-Litang suture zone to the east, rather than with the Jinshajiang suture zone to the southeast. The magma source of the basalts in the Yushu melange was changed from garnet lherzolite to spinel lherzolite during Permian-Triassic period, corresponding to the rifting and spreading processes of the Ganzi-Litang Paleo-Tethyan ocean.

Abstract:The high-Mg diorites occur in the Shibanjing area of central Beishan orogenic belt and are dated at 456±2 Ma by the LA-ICP-MS zircon U-Pb method, which indicates that they were generated in the Late Ordovician. According to geochemical data, the high-Mg diorites belong to the sodic calc-alkaline series, the content of SiO₂ is 51.94%~55.30%. They are geochemically characterized by high MgO (4.12%~6.19%, avg. 5.17%), Mg^# (0.45~0.69, avg. 0.53), Cr (35.82×10^-6~985.50×10^-6, avg. 284.84×10^-6), and Ni (20.93×10^-6~148.59×10^-6, avg. 70.23×10^-6), and also exhibit nearly flat right-declined REE patterns with slight enrichment of LREE. The high-Mg diorites are strongly enriched in large-on-lithophile elements such as Rb, Ba, Th, U and K, and are characterized by depletion of high-field-strength elements such as Nb, Ta, P and Ti. These geochemical features are analogous to those of Cenozoic Setouchi volcanic belt in southwestern Japan. Petrogenesis analysis shows that the rock mass was probably formed by the interaction between the aqueous fluid produced by partial melting of subducted oceanic crust and sediments and the mantle peridotite, suggesting that it was formed in an island arc environment. It is thus concluded that the Hongliuhe-Niuquanzi-Xichangjing ancient ocean plate was presumably in the process of subduction during the late Ordovician, and the collision between Kazakhstan plate and the Tarim plate might have occurred after Ordovician.

Abstract:A lot of porphyry deposits, related to potassic intrusions closely, occur in the Jinsha-Ailaoshan metallogenic belt, western Yunnan. Liuhe orthophyre is barren magmatic rock and is located at the center of the belt. Based on petrography, the authors studied mineral characteristics of biotite, amphibole and zircon in Liuhe orthophyre, and investigated mineral temperature-pressure condition, magmatic oxidation state and water content. Depending on geochemical data and previous studies, the authors discussed the constraining condition for mineraliza-tion of potassic intrusions. Biotite has high MgO (12.98%~14.83%), CaO (14.18%~16.52%) content, with Fe²⁺/(Mg+Fe²⁺) ratios being 0.29~0.31. Mineral thermobarometric calculations show that crystallization temperatures of biotite are 615~669℃ under the pressure of 103~165 MPa and at the depth of 3~5 km (4.2 km on average). Amphibole consists dominantly of endenite and pargasite. Crystallization temperatures of amphibole are 817~843℃ under the pressure of 158~191 MPa and at the depth of 5~6 km (5.9 km on average). Oxygen fugacities (△FMQ) of magmas, constrained by chemical composition of amphibole, are +1.12~+1.27. Crystallization temperatures of magmatic zircons are 687~1 098℃ and Ce⁴⁺/Ce³⁺ ratios are 11.18~54.78 (Ce⁴⁺/Ce³⁺<50 on average), δEu=0.14~0.81 (δEu<1). Liuhe orthophyre has δEu ratios of 0.97~1.00, and whole-rock Dy/Yb ratios have negative relation and La/Yb ratios have positive relation with SiO₂ values, respectively. In addition, amphibole occurs as phenocrysts. These features indicate that a lot of amphibole crystallized at the early stage whereas crystallization of plagioclase was suppressed. The authors hold that Liuhe orthophyre had low oxygen fugacity and high H₂O content. Compared with mineral characteristics of fertile magmas of porphyry deposits, Liuhe orthophyre has no potential to form porphyry deposits.

Abstract:The Lujing deposit is a typical veined Pb-Zn deposit in west Damingshan area, and its orebodies are located in the Cambrian strata and strictly controlled by faults. Based on detailed field geological survey as well as analysis and interpretation of fluid inclusions, sulfide mineral chemistry and S isotope, the authors investigated ore-forming fluid properties and sources of ore-forming mineral. Petrographic observations reveal that the inclusions at stage Ⅱ of Lujing deposit primarily belong to liquid-rich, single-phase aqueous fluid inclusion. Microthermometric measurements indicate that homogenization temperatures are 237~281℃ (256℃ on average), with corresponding salinities of 3.54%~12.69% (8.39% on average). Electron microprobe analysis indicates that, characterized by high content of Fe, Cd and Cd and low content of Mn, Ga and Ge, sphalerites should belong to high temperature iron sphalerite. The δ³⁴S values of sulfides vary from -1.9‰ to 4.4‰ (1.7‰ on average), close to zero on average, which indicates that sulfur of the sulfide was derived from the magmatic source. Based on ore-forming geological characteristics, fluid inclusions, sulfide mineral chemistry and S isotope, the authors hold that the Lujing deposit should belong to hydrothermal vein type Pb-Zn deposit, that mineralization of Lujing was closely related to the magmatism, and that the deposit was formed in late Yanshanian period.

Abstract:The Chating copper-gold deposit in Xuancheng City of Anhui Province is a large porphyry deposit newly discovered in the middle and lower reaches of the Yangtze River metallogenic belt. Based on detailed ore mineragraphic research, the authors carried out the measurement of ore-forming element concentrations of main minerals from the ores by EMPA and chemical analysis, with the purpose of studying the modes of occurrence of gold and the genetic connection between gold and copper in this deposit. The hydrothermal mineralization period of the Chating copper-gold deposit was divided into 4 stages. The fire assay analysis results of single mineral show that the pyrites at the second stage (PyⅡ), the pyrites at the third stage (PyⅢ) and the chalcopyrites at these two stages are rich in gold, whereas the quartzs at all stages and anhydrites at the third stage contain almost no gold. "Visible gold" was found in the ores and they are mainly embedded as inclusion gold and interparticle gold, with a small amount of fissure gold. The major minerals of the "visible gold" are electrum, followed by native gold. "Invisible gold" is distributed unregularly in the sulfide minerals such as chalcopyrite, pyrite, sphalerite and bornite. And the "invisible gold" exhibits nanoparticle native gold in pyrite. The correlation between gold and copper and the modes of occurrence of gold show that gold and copper have a close genetic connection. Simon's experimental study reveals that the solubility of Au in Cu-Fe sulfide is very high at high temperature. The mineralization of the Chating copper-gold deposit underwent the evolution from high temperature to low temperature. As the temperature decreased, part of gold was exsolved from Cu-Fe sulfides and became enriched as "visible gold"; while the other part remained in the form of "invisible gold" preserved in chalcopyrite, pyrite, sphalerite and other copper-bearing sulfide minerals.

Abstract:In this paper, the authors made a comparative study of the geochemical characteristics of trace elements and REE for various rocks such as granites and dolerites as well as uranium ores from the Shangjiao uranium deposit of southern Jiangxi. The ore-forming material source and metallogenic model of the Shangjiao uranium deposit were discussed. Based as geological and elemental geochemical data, the authors have reached some conclusions:① The high U content and low Th/U values of early Indosinian granites and early Yanshanian granites suggest that both granites had the capability of providing adequate sources of uranium for uranium mineralization in the study area, and the potential of early Yanshanian granites for providing the sources of uranium was even greater; ② There was almost no change in the content of trace elements and REE and distribution patterns during hydromicazation of granites, but there occurred uranium enrichment and mineralization and REE remobilization during the superposition of hematitization. These phenomena imply that hematitization was more closely related to uranium mineralization in the study area; ③ The trace elements distribution patterns of dolerites show mantle characteristics, significantly different from features of granites and uranium ores, and the U content and U/Th ratios of altered dolerites are obviously higher than those of fresh dolerites, which suggests that the ore-forming material of the Shangjiao uranium deposit was not derived from dolerites. Large areas of hematitization imply that dolerites provided ore-forming components and volatiles(CH₄, CO, CO₂, H₂S and Fe²⁺) for oxidation-reduction reaction of uranium mineralization, so that the migration of U⁶⁺ experienced deoxidation to form U⁴⁺ and precipitated mineralization material; ④ The trace elements distribution patterns of uranium ores and granites show high similarity and gradual relationship, indicating that ore-forming material was derived from granites. The total REE content of uranium ores is obviously lower than that of granites and dolerites, indicating that the ore-forming fluids were characterized by a lack of REE. In combination with the geological background of mineralization, the characteristics of magmatic-structure-alteration and geochemical characteristics of trace elements, the authors have improved the metallogenic model of the deposit.

Abstract:The Jiashi copper deposit is a typical representative of sandstone-type copper deposits in the Keping basin. Many geologists have studied its genesis, but have no detailed geochemical evidence. According to research findings of this paper, the metallogenic period of the deposit can be divided into diagenetic metallogenic period and reformation metallogenic period, with the former being the main stage. In this paper, the relationship between the ore-forming fluids evolution and mineralization was investigated by means of microthermometry, composition analysis, hydrogen, oxygen, and carbon and sulfur isotopes of fluid inclusions in the two metallogenic periods of the deposit. According to the results obtained, the ore-forming fluids in the diagenetic period had the homogeneous temperature 131~206℃, salinity 0.35%~9.86%, density 0.90~0.99 g/cm³, and pressure 227~464 MPa; in the reformation period, the homogeneous temperature was 131~285℃, salinity was 0.53%~9.34%, density was 0.78~1.00 g/cm³, and pressure was 231~448 MPa. The ore-forming fluid was of medium low-temperature, medium-pressure, low-salinity and medium density type, and it had typical characteristics of underground hot brine. The δ³⁴S values range from -34.5 ‰ to -22.7 ‰, indicating that the sulfur of the deposit was mainly derived from sulfate bacteria reduction and organic matter reduction. The δD values of inclusions of diagenetic period are -105.4‰~-79.2‰, δ¹⁸O_H2O are -3.13‰~0.87‰; in the reformation period the δD values are -108.5‰~-81.3‰, and δ¹⁸O_H2O are -4.21‰~4.04‰, indicating that the ore-forming fluid was the mixed source of atmospheric precipitation and basin brine, with the addition of organic water. The δ¹³C values at the diagenetic stage range from -28.4 ‰ to -24.2‰, and during the reformation period the values range from -28.5‰ to -23.0‰, in agreement with the negative range characteristics of natural organic carbon δ¹³C. Laser Raman probe composition analysis shows that the main components of the ore-forming fluid of the deposit during the diagenetic period and reformation period were mainly CH₄, H₂S and H₂O. It is shown that the organic matter in the oilfield brine was involved in the metallogenic process during the diagenetic period and the reformation period, and played an important role of reduction in the ore-forming process of the Jiashi copper deposit. This study shows that organic matter was closely related to the mineralization of the Jiashi copper deposit, which was a sedimentation-reformation type sandstone copper deposit in which the oilfield brine took part in the mineralization.

Abstract:In this paper, the authors analyzed the characteristics of the CIA distribution curve of Liantuo Formation in Nanhua System in South China, and compared different CIA values as well as their explanations for the paleoclimate. Compared with the lithofacies-paleoclimate analysis method, the result does not show consistency in the paleoclimate characteristics. By means of analog method and in comparison with the cold paleoclimate of the overlying Nantuo Formation, it is found that the interglacial period sediment is very monotonous in Nantuo Formation, whereas it is abundant in Liantuo Formation and has various sedimentary structures. The factors controlling the accuracy of CIA values mainly include the lithology of samples, sampling precision and the source-to-sink system. It can be said that the source rock composition and weathering denudation determined the types of sediments in the basin formation. In addition, the later diagenesis and regional transformation should not be ignored. Therefore, it is believedthat the CIA value application must be combined closely with the traditional sediment facies and paleoclimate analysis, which can prevent any missing in the explanation and obtain the best results.

Abstract:The Liwu-type copper deposits are located in the Jianglang dome, one of the domes in the southeastern Songpan-Ganzi fold belt. Based on field investigations and detailed observations, the authors identified two metallogenic processes:banded sulfide ores occurred at the early stage, and massive, disseminated and veined ores were undeformed and superimposed on the early mineralizations at the late stage. In this paper, the authors present the first chalcopyrite Re-Os geochronological data for the Liwu and Zhongzui deposits to exactly constrain the formation age and origin of the metallogenic event. The result yielded a good isochrone age of 343±11 Ma (n=4, 2σ), with an initial ¹⁸⁷Os/¹⁸⁸Os ratio of~2.37. This study indicates that the early banded (deformed) copper mineralization was initiated in the Early Carboniferous, later than the Meso-proterozoic surrounding rocks of the Liwu Group. The main ore-forming source should have been derived form the upper continental crust.

Abstract:Using conventional gemological methods, SEM, FTIR spectrum, Raman spectrum and UV-VIS spectrum analysis, combined with the processes of treatment and the mixture of glue, the authors found out the best way to distinguish the dipped turquoise, injected turquoise and the natural ones. The color of injected turquoise is stiff, while the color of dipped turquoise and injected turquoise under the long-wave UV fluorescent lamp is pale to strong blue. The authors found glue in dipped turquoise and injected turquoise under SEM, which could help differentiate three kinds of turquoise; however, this method is ruinous. The result shows that FTIR spectrum can differentiate Hubei turquoise from dipped turquoise and pigmented turquoise with 2 930, 2 860, 1 730, 1 460 cm^-1 absorption bands caused by the vibration of organic groups; this is the fastest, accurate and non-destructive testing method; meanwhile, 2 942, 2 873, 1 452, 1 620, 830 cm^-1 absorption peaks in Raman spectra are beneficial to distinguish the dipped turquoise and pigmented turquoise with the natural ones; UV-VIS spectra of the weaker 429 nm absorp-tion peak and the 677 nm absorption band can be used as the identification basis to distinguish the natural turquoise and pigmented turquoise, but they are unable to distinguish between natural turquoise and dipped turquoise.

Abstract:In order to explore the metallogenetic substances, environment and ore-forming age of Sanchakou, Tuolahaigou and Dazaohuo nephrite deposits in NS-trending metallogenic belt of Qinghai, the authors conducted Ar-Ar dating and analysis of major elements, trace elements and rare earth elements (REE). Major elements analysis shows little change in all samples from three deposits, which is in accordance with theoretical value of tremolite. The content of rare-earth elements in all samples is generally lower (0.29×10^-6~40.72×10^-6), with moderately negative Eu anomalies (0.49~0.84). Except for green nephrite, the chondrite-normalized REE patterns of samples exhibit relative light REE (LREE) enrichment and right-declined REE distribution patterns, with (La/Yb)_N values ranging from 2.87 to 6.34. Green nephrite samples are characterized by the enrichment of heavy REE (HREE) in the left-declined REE distribution patterns, with (La/Yb)_N values ranging from 0.16 to 0.61. REE distribution curves of samples from Sanchakou and Tuolahaigou nephrite deposits are similar to the patterns of Nachitai basic gabbro, and yellow nephrite samples from Dazaohuo deposit in northern metallogenic belt are similar to monzonitic granite, whereas green nephrite samples are similar to plagiogranite. The results indicate the source of mineralization of different deposits. The change of the content of Ti and Al₂O₃ in the sample shows changes in metallogenic temperature and pressure. The ratios of Zr/Hf, Nb/Ta and Sr/Ba in viridite and yellow nephrite samples are significantly lower than those of other samples, indicating that the alkalinity of metallogenic environment was obviously enhanced. The Ar-Ar dating shows that ore-forming ages of three deposits (301.38~237.28 Ma) are between Late Devonian to Middle Triassic, later than the geological age of intrusive rocks. The results indicate that Qinghai nephrite was mainly formed in the Hercynian-Indochina period, corresponding to multiple mineralization processes.

Abstract:In this study, self-supporting zeolite NaP was synthesized from fly ash-based geopolymer via in-situ hydrothermal method. The effects of various factors, such as hydrothermal temperature, crystallization time, concentration and volume of sodium hydroxide (NaOH), on the crystallinity, morphology and mechanical strength of the resulting products were investigated. Optimal conditions for the synthesis of zeolite NaP from fly ash-based geopolymer were determined to be as follows:temperature 100℃, curing time 24 h in the 50 mL of 2.0 mol/L NaOH solution. The compress strength of zeolite NaP is 23.21 MPa with specific surface area of 50.46 m²/g, which can meet the industrial manufacturing and production standards. The in-situ hydrothermal method is a facile, environment-friendly and controllable method for the preparation of self-supporting zeolite. Moreover, different types of zeolites can be synthesized by controlling the raw material compositions and reaction conditions.

Abstract:The adsorption of strontium from aqueous solution with heavy metal chelate fiber was studied. The effects of several experimental parameters such as pH, dosage, temperature, contact time and initial concentration of strontium on adsorption efficiency of strontium were investigated. The adsorption mechanism of strontium ions by ZH heavy metal chelating fiber was discussed by contemporary analytical testing methods such as SEM, SEM-EDS and FTIR analysis. The results indicated that, under the conditions pH=7.0, biomass dose=2.0 g/L, the initial concentration of strontium ions=50.0 mg/L, and adsorption time=4 h, the fibers exhibited the best biosorption capacities. The biosorption equilibrium indicated that the process was mainly based on monolayer adsorption combined with multi-molecular layer adsorption. The results indicated that the maximum adsorption capacity of Sr²⁺ by ZH heavy metal chelating fiber was 26.22 mg/g. The equilibrium sorption capacity of strontium was determined from the Langmuir equation, and the dynamic adsorption process conformed to the secondary dynamic model. FTIR analysis found that Sr²⁺ was coordinated to -NH₂ and -COOH on the surface of fibers, and -CH₂- and C=CH₂ were involved in the adsorption. DES analysis indicated that there was ion exchange between Sr²⁺and Na⁺, Ca²⁺ on fibers.

Abstract:Nano-hematite with multi-porous texture was prepared from the transformation of limonite by thermal treatment. The prepared nano-hematite was utilized to remove Mn²⁺ from aqueous solution. The effect of heat treatment temperature, initial pH, Mn²⁺ concentration and contact time on removal of Mn²⁺ was investigated. The results of characterizations (XRD, TEM, BET) showed that the hematite exhibited the smallest pore size of 2.7 nm and the largest surface area of 107.4 m²/g after thermal treatment at 300℃. The results of batch experiments indicated that the effect of pH varying from 5 to 10 on the removal of Mn²⁺ was marginal and could almost be ignored. The maximum adsorption capacity of the thermally treated limonite to Mn²⁺ reached 6.45 mg/g. The kinetics results showed that the adsorption of Mn²⁺ by nano-hematite followed pseudo second-order kinetic model. The prepared nano-hematite presented excellent adsorption performance and catalytic oxidation to Mn²⁺. Furthermore, the existence of manganese oxide promoted the adsorption performance and dramatically improved the role of catalytic oxidation in removal of Mn²⁺ from aqueous solution.