Abstract:With the drill hole ZK23-2 as the object and the microscopic slice identification and the geochemical analysis of fluid inclusions of the ore-forming period as the main means, this paper mainly studied wall rock alteration of the No. 302 uranium deposit,. The results show that the ore deposit has a variety of alterations, which are composed of such types as alkali feldspathization, silicification, sericitization, hematitization, chloritization, epidotization, carbonation, and kaolinitization. The ore deposit shows obvious vertical and horizontal zoning. From the top to the bottom of the ZK23-2 drill hole, four alteration zones were recognized, i.e., red-sericitization zone→silicification-intense red alteration-sericitization zone (uranium enrichment zone)→chloriti-Zation-sericitization zone→ weak alteration or normal granite zone. Major elements, trace elements and rare elements in the rock show regular variations. The altered rock has preserved the same geochemical characteristics as the ore-hosting Changjiang rock body, as can be seen from the consistency of their distribution patterns of trace elements and rare elements. Homogenization temperatures of fluid inclusions in different alteration zones are all below 220℃, belonging to moderate-low temperature hydrothermal fluids. As for chemical components of fluid inclusions, inert gas N2 appears at all the alteration zones, and gaseous CO2 exists in the strong alteration zone, suggesting that the dissolution, migration and enrichment of uranium were related to gaseous CO2 and occurred in gaseous N2 environment during the formation of the uranium deposit. In addition, a study of fluid inclusions in the ore-forming period shows that characteristics of different wall rock alteration zones might have resulted from the mixture of ore-forming hydrothermal fluids.

Abstract:With the development of the in situ zircon SHRIMP U-Pb dating method and laser ablation ICP-MS, the study of the age distribution of detrital zircons from sedimentary rocks has become an effective way to find the source area of clastic material and also become an important topic all over the world. However, during zircon laser ablation (LA)-ICPMS dating, the U-Pb isotopic fractionation remains one of the principal obstacles for precise zircon dating. The experiments performed by the authors demonstrate that a low laser frequency (5 Hz or 6 Hz) would reduce element fractionation during laser ablation. The U-Pb ages of international zircon standards GJ-1 and the laboratory zircon standard SK10-2 were measured by LA-ICP-MS in 20 μm spot size at 5 Hz laser frequency. The reduce mean 206Pb/238U ages obtained in our analysis are in good agreement with the published values. Quartz sandstone from Changlongshan Formation of Qingbaikou System, the oldest metasedimentary rock in Liujiang area of Qinhuangdao City, was deposited unconformably on the Neoarchean potassic granite. Detrital zircons from the quartz sandstone have 207Pb/206Pb ages of 2635 Ma to 2487 Ma. A comparison with the Beiijng-Jixian stratatigrphic section, from Early Proterozoic, the study area experienced a long period of weathering and erosion, and then began to deposit on the surface and become the source area of clastic sediments of the Changlongshan Formation until the early Neoproterozoic. Hf isotopic compositions of the detrital zircons indicate that the clasts were main-ly derived from the reworked ancient crust, suggesting that the mass of the continental crust was largely established at ～2.5 Ga in its source area.

Abstract:Located near Pantuoshan district in Ejina Banner of southwestern Mongolia, Guoqing K-feldspar granite body lies in southern Niujuanzi-Xichangjing suture zone. LA-ICP-MS U-Pb isotopic dating of zircon separated form the rock yields an average weighted 206Pb/238U age of 439.1±8 Ma. The results of geochemical study indicate that SiO2 are in the range of 73.31%～74.36%， A/CNK>1.1, and K2O/Na2O=1.25～1.40, the Rittmann index of k-feldspar granite varies from 2.06 to 2.22, suggesting a high-K calc-alkaline series and peraluminous nature. The results also indicate that Guoqing K-feldspar granite body is highly enriched in large ion lithophile elements and strongly depleted in high field strength elements. The chondrite-normalized REE and trace elements patterns demonstrate low fractionation level between LREE and HREE, (La/Yb) N=3.40～5.44, and negative Eu(δEu=0．65～0．77), which might have been related to the plagioclase residuals during the partial melt of the original rock. The spider diagrams are characterized by Nb, Ce, Zr, Hf, Sm, Y, Yb depletion and K, Rb, Ba, Th enrichment. Rb/Sr ratios are between 4.37 and 4.70, and such high Rb/Sr ratios (>2) suggest that Guoqing granite body was probably triggered by dehydration melting of mica during the geological process. High levels of Nb and Ta and characteristics of Ta>Nb indicate high-degree evolution of the granite body, which laid the foundation of tungsten elements enrichment. CaO/Na2O ratios range from 0.152 to 0.165, and all the values are lower than 0.3, suggesting the origination from re-melting of the early Precambrian crystalline basement. In addition, the inherited zircon in the granite body yields a large number of ages between 616 Ma and 1046 Ma. In Hongliuhe area, the zircon U-Pb age of granite that intruded into ophiolite is 404.8±5.2 Ma, implying that the south Tianshan oceanic crust was formed as early as Early Cambrian, and closed before Emsian. In Xichangjing area, the closure of South Tianshan Ocean was before 439.1±8 Ma, suggesting a scissors-type opening-closing tectonic pattern. The results of geochemical study show that the S-type K-feldspar granite, which was crust-derived, might have been formed by the closure of the Hongliuhe-Yueyashan Paleo-ocean during the syn-collision stage. There are Yingzuihongshan, Wangxushan and Guoqing tungsten ore deposits in Xichangjing area. These ore deposits which were formed in the contact zone or the fissure system surrounding the granite intrusion have a close relationship with Silurian-Devonian granite intrusions. Moreover，in the tectonic setting of transformation from collision to extension from Silurian to early-Devonian， the granites related to such tectonic settings deserve detailed studies, which can not only help understand the tectonic evolution but also provide a theoretic basis for the exploration of regional mineral resources.

Abstract:It is generally accepted that the volcanics-hosted massive sulfide deposits were widely derived from the marine settings, such as island arc, back-arc basin, mid-ocean ridges, and intraplate spreading centers. Different tectonic regimes are typically marked by changes in the composition of the associated marine volcanic rocks and different ore mineral assemblages in volcanic massive sulfide deposits. Volcanic rocks from Renzhixueshan Formation in Shangdie rift basin of Sanjiang is an important layer hosting volcanic massive sulfide deposits. However, the time of their formation has been controversial. The major rock types of Renzhixueshan Formation are basalt, rhyolites and bimodal volcanic rocks. LA-ICPMS U-Pb zircon dating of two rhyolite samples from Renzhixueshan Formation in Jijiading area yields concordant 206Pb/238U ages of 247.4±2.1 Ma and 249.1±1.6 Ma, respectively, implying that these rocks were erupted in early Triassic (249～247 Ma). The geochemical and isotopic characteristics indicate that the basaltic volcanic rocks were probably produced by partial melting of an enrichment mantle. The similar Sr-Nd isotopic compositions of rhyolite to the basalt suggest that they were probably triggered by the same tectonic event. These characteristics of volcanic rocks in Renzhixueshan Formation suggest that they were probably formed in an extending dynamic settings. Therefore, the authors hold that Jinshajiang suture had already been an extending setting after the arc-continental collision during the early Triassic in the Jijiading area of east Tibet. At the same time, the extensional settings probably played an important role in the formation of volcanics-hosted massive sulfide deposits in the Jinsha orogenic belt.

Abstract:The Hualong Rock Group of South Qilian orogenic basement remnants hasaroused much interest among geologists for the occurrence of basic-ultrabasic rocks closely related to Cu-Ni (-PGE) ore deposits. With the acquisition of some precise Neoproterozoic zircon isotopic age data， the traditional understanding that Hualong Rock Group was formed in Archean-Paleoproterozoic has been challenged. High resolution LA-ICP-MS zircon U-Pb in situ dating of banded two mica-plagiogneiss (para-metamorphic rocks) from Hualong Rock Group in Riyue village of southern Huangyuan County yielded an age of 891±7 Ma, which represents the lower age boundary of Hualong Rock Group. The age recently obtained from banded biotite-plagioclase amphibolite (whose protolith was intermediate volcanic rocks) is 884±9 Ma. Based on isotopic dating combined with the results obtained by previous researchers, the authors further restricted the age of Hualong rock Group to Early Neoproterozoic, i.e., Qingbaikou period. It is believed that the volcano-sedimentary rocks of Hualong Rock Group serve as geological records of the breakup of the Rodinia supercontinent. Recently, zircon U-Pb dating yielded an age of 724.4±3.7 Ma from gneissic plagioclase amphibolite (whose protolith was gabbro)near the Dadaoerji Cu-Ni ore deposit in the western part of the Qilian orogenic belt, whereas a U-Pb age of 724.4±3.7 Ma was yielded from zircon and baddeleyite in Jinchuan ultrabasic rock of Longshou Mountain area in northern Qilian orogenic belt; these data can also be regarded as geological records of the breakup of the Rodinia supercontinent. These results indicate that the importance of Rodinia supercontinent breakup event and its related mineralization in Precambrian period of the Qilian orogenic belt and its adjacent areas should not be underestimated.

Abstract:There are many lead-zinc polymetallic deposits related to continental collision in Lanping Basin, western Yunnan Province. These deposits were formed in a continental collision environment, developed in a strong deformation sedimentary basin, controlled by thrust structure, had no obvious affinity to igneous activities and belong genetically to epigenetic mineralization. Thus they are significantly different from Sedex-type Zn-Pb deposits produced in the passive continental margin and also different from marine sandstone-type Pb deposits (SST) and sandstone-type Cu deposits (SSC). Although they are similar to the MVT lead-zinc deposits, they are not the typical characteristics of MVT lead-zinc deposits in such aspects as basin environment, structural location, source material, metals and ore combination. Therefore, due to their unique characteristics, they are an important research object for the comprehensive understanding of the sediments-hosted base metal mineralization. In the past, less researches have been devoted to the lead-zinc polymetallic deposits in Fulongchang area, and hence the relationship between the different deposits is not clear. On the basis of geological field observations, the authors selected sphalerite which exist in all these deposits as the object to study its trace elements and S-Pb isotopic composition so as to make a comparative analysis. On the whole, these deposits are developed in the thrust nappe structure system and the secondary faults caused by thrust, have no obvious wall rock affinity, and show injection filling epigenetic mineralization in the fault system. The ore minerals include not only sphalerite, galena, pyrite, gratonite and tetrahedrite but also cinnabar, realgar and orpiment, with the main gangue minerals being calcite, assuming a low temperature hydrothermal mineral assemblage. Ore structures mainly include brecciated, veinlike, massive, disseminated, spotted and banded structures. The mineral textures are mainly euhedral granular, hypidiomorphic granular, xenomorphic granular and saccharoidal textures. Besides Zn-Pb, these ore deposits also have Cu and Ag, showing features of Pb-Zn-Cu-Ag polymetallic assemblage. Wall rock alteration is mainly carbonation. The three deposits have rich Cd, poor Ge and Ga, inversely related Fe-Cd, low average ratios of Zn/Cd in sphalerite. δ34S values of sphalerite in the three deposits are basically consistent, have a narrow range, and show peaks at 5‰～6‰. Lead isotope values of sphalerite from different ore deposits are basically in coincidence. In the diagrams of 207Pb/204Pb－206Pb/204Pb and 208Pb/204Pb－206Pb/204Pb, the main data are located between the upper crust line and the orogenic belt line. In the Δβ－Δγ diagram, the whole values fall into the upper crust lead zone and the mixed range of the upper crust lead and the mantle subduction zone lead. Compared with the values of different metal source end-members in Lanping basin, the value of Pb isotope in sphalerite is consistent with the values of the Mesozoic and Cenozoic sedimentary rocks. Therefore, the lead-zinc polymetallic deposits in Fulongchang area must have been formed at the same ore-forming fluid activity in different spatial locations, being of the same origin. Meanwhile, the ore-forming temperature was of middle-low temperature, and sulfur was probably derived from the thermochemical sulfate reduction of organic matter in the basin or the decomposition of sulfur-bearing organic matter. The metals for mineralization might have come from regional sedimentary strata.

Abstract:Taking the volcanic reservoir of Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field as an example, the authors studied lithofacies characteristics of the volcanic gas reservoir and their influences on reservoir physical properties with the purpose of effectively forecasting and exploiting the volcanic reservoir. On the basis of identification of volcanic rock types and recognition of volcanic rock bodies by combining geological data with logging data and seismic data, the authors analyzed volcanic lithofacies characteristics and their relationship with reservoir physical properties and forecast the favorable prospecting areas by using data from wells, sections and plane lithofacies. The results indicate that the volcanic reservoir of the Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field was formed by repeated volcanic eruptions, with the lithologies consisting of 10 types. The rhyolite, rhyolite tuff and sedimentary volcanic breccia played the preponderant role. The eruption type in the study area was cranny-center eruption, and crater and volcanic lithofacies were obviously controlled by ruptures. The volcanic bodies were dominated by craters, and different volcanic lithofacies were developed in different positions of volcanic bodies. The volcanic facies inside the volcanic bodies in the study area can be divided into five types and sixteen sub-facies. The results indicate that the volcanic lithology and its combination constitute the basis of the division of volcanic facies, and the spreading of volcanic facies controls the distribution of gas reservoirs. The reservoir development areas include the lower part and upper part and top overflow sub-facies of overflow facies, splash down sub-facies and air falling sub-facies, middle extrusive sub-facies, exterior sub-facies of extrusive facies and volcanic neck sub-facies of volcanic channels facies. The sub-facies of the volcanic reservoir include volcanic sub-lithfacies of volcanic neck sub-facies, dikes, sills, hydrothermal breccias, inner extrusive sub-facies, middle extrusive sub-facies, exterior sub-facies, splash down sub-facies, pyroclastic flow deposit, base surge deposit, air falling sub-facies, top part overflow facies, upper part overflow facies, middle part overflow facies, lower part overflow facies, epiclasts-bearing volcanogenic sediments and reworked volcanogenic sediments. The explosive facies and overflow facies are most developed facies, and the physical property of the volcanic sub-facies of splash down is the best. The average effective porosity is 9.00% and the average whole permeability is 4.793 mD. Volcanic lithology and its combination form the basis of the division of volcanic lithofacies. The distribution of volcanic lithofacies control the development characteristics of volcanic reservoirs. The reservoir development areas are lower part and upper part and top overflow sub-facies of overflow facies, splash down sub-facies, air falling sub-facies, middle extrusive sub-facie, exterior sub-facies of extrusive facies and volcanic neck sub-facies of volcanic channels facies.

Abstract:Skarn and hydrothermal vein deposits constitute the main resources of lead and zinc in the Gangdise metallogenic belt. In recent years, especially since the beginning of the Geological Survey Project in 1999, great progress in geological survey and resource exploration has been made, several large-size lead and zinc ore deposits have been discovered, and many important regional geological data have been accumulated in Gangdise region. Based on detailed collection of geological, ore deposits, minerals, geophysical and geochemical data and remote-sensing information in this region, the authors established a mineral resources evaluation system based on GIS technology. The basic data of the mineral resources evaluation system cover a wide range of information, which includes geology (stratigraphy, tectonics, magmatic rocks and metamorphic rocks), minerals (ore deposits and mineralized spots), geophysical data (magnetic and gravitational method), geochemical data (individual and composite Cu, Pb, Zn, Ag, Cd and Au geochemical anomalies) and geography. Using characteristic analysis model and mathematical statistics, the authors determined the metallogenic model and quantitative geological variables for prognosis of skarn and hydrothermal veinlike lead and zinc deposits respectively, which constitute the dominant lead and zinc ore types in the Gangdise metallogenic belt. The result has shown that the most important geological factors for the prognosis of lead and zinc deposits include intermediate-acid granitic intrusive bodies, known ore deposits and mineralized spots, individual Cu, Pb, Zn, Ag, Cd, Au, Bi geochemical anomalies, composite Cu-Pb-Zn-Ag, Pb-Zn, Pb-Zn-Ag-Cd geochemical anomalies, positive-negative change of magnetic anomalies, and middle-low negative gravity anomalies. According to the calculation of the MRAS system (developed by Institute of Mineral Resources, CAGS), 57 target areas for skarn and hydrothermal vein lead and zinc deposits were delineated in the Gangdise metallogenic belt. The results obtained by statistics are in well accord with the geological deduction. The lead and zinc reserves were estimated by the areal productivity method, which shows that there still exists great potential for lead and zinc deposits in Gangdise region, and that the predicated lead and zinc reserves within the depth of 1000 m are over 290 million tons. The most potential lead and zinc target areas mainly include Yaguirang-Sharang-Dongzhongsongduo, Bangpu-Songduoxiong-Xiamari-Nongruri, Zexue lead and zinc deposits, Bengbunong gold deposit, Mengyaa-Longmala etc., in which the potential lead and zinc reserves are over 20 million tons.

Abstract:The Huanggang Sn-Fe deposit is a large-size skarn deposit hosted by Lower Permian marble of Huanggangliang Formation. Its skarn mineral assemblage mainly consists of diopside, andradite-grossular and vesuvianite, and its retrograde minerals include actinolite-tremolite, epidote, chlorite, sericite, grossular etc. Electron microprobe analyses show that the end member of garnet in the early stage is dominated by andradite, while that in the major ore-forming stage is dominated by grossular, and that the end member of pyroxene has changed greatly, composed mainly of diopside and hedenbergite. Components of garnet and pyroxene are Adr28.69～96.44Grs2.00～67.38 (Prp+Sps) 0.67～5.69 and Di11.8～94.12Hd4.08～81.28Jo1.79～20.02, respectively, their wide compositional variation range suggests that skarns were not formed under the totally enclosed equilibrium condition. The amphiboles mostly belong to magnesium-ferric-calcium amphibole, with only some individuals being ferric-hornblende. The relatively remarkable change of composition is probably attributed to the change of redox conditions resulting in different degrees of AlⅥSi←→(Na, K) displacement, which belongs to the transforming tendency under solidus. Tetrahedral Si, Al, octahedral Al, Ti and cations in A site of amphibole change greatly, which may be caused by the composition difference of the magma in the contact metasomatic process or the change of physicochemical condition during crystallization. Electron microprobe analysis shows that the early skarns in Huanggang belong to the typical oxidation type, while the late skarns transfer to the reduction type. From the viewpoint of mineral assemblages, the skarn assemblage in this area is similar to the calcareous skarn formation. Composition characteristics of skarns in the Huanggang Sn-Fe deposit are similar to those of Cu-Fe deposits of calcareous-magnesian skarn formation, while the altered mineral assemblage is close to W-Sn deposits of the calcareous skarn formation, indicating a new skarn formation. Massive intrusion of granitic magma brought a lot of metallogenic materials and heat energy needed for mineralization. In addition, the well developed faults in the Huanggang ore district also provide a channel for fluid migration. A lot of laminar skarn ores are developed in this area, and as this uniform banded structure cannot be observed in peripheral marbles, these laminar rocks seemed to be a self-organization phenomenon in the process of metasomatism and were not formed by sedimentary-exhalation. Mn/Fe ratios of pyroxenes in the Huanggang ore district range from 0.15 to 0.44, suggesting that the possibility of finding polymetallic mineralization in this area. The johannsenite in pyroxene changes remarkably in composition, and its content ranges from 1.79% to 20.02%. There is no Mn in the marble of Huanggangliang Formation of the ore-bearing strata in the Huanggang Sn-Fe ore district, and the possibility of the derivation of Mn from the strata is very small. In contrast, the pyroxenes are Mn-enriched in the stratiform ore body away from the contact zones or ore bodies containing no Mn. MnO content (0.02%～0.05%) in Huanggang granites is significantly lower than the average content of MnO (0.07%) in A-type granite, and there exist no Mn-enriched accessory minerals such as ilmenite, indicating that there might have been the participation of some Mn composition of granitic magma in the skarn due to contact metasomatism. Therefore, the Mn-enriched pyroxenes probably resulted from the evolution of Mesozoic magmatic fluid, and Mn-enriched pyroxene skarns were formed by infiltration metasomatism of magmatic fluid along fracture zones between layers. These phenomena are similar to things of the skarn Pb-Zn deposits in central Fujian Province. Mn-rich pyroxene might serve as the indications for Sn, Cu, Zn and many other metallic ores in this area, and the outer contact zone of skarn and its periphral marble seem to be favorable positions for polymetallic mineralization.

Abstract:The cementation of quartz is one of the very common and important diagenetic actions in sandstone reservoirs. A thorough study of the characteristics and formation mechanism of autogenetic quartz is therefore an indispensable means in revealing the reservoir characteristics, analyzing the evolution of diagenesis, and forecasting and evaluating the reservoir. According to the formation mechanism of serrated edges and the microscopic features of quartz in Lower Shihezi Formation and underlying Shanxi Formation, the authors found two corrosions and one overgrowth, with the corrosions taking place respectively before and after the overgrowth. The dissolution of feldspar is considered to be one of the main siliceous sources on the basis of the dissolution theory of feldspar and the residual structural analysis. The distribution of authigenic minerals is characterized obviously by the gradual upward decrease of quartz, the positive correlation with authigenic calcite and kaolinite, and the negative correlation with illite. Therefore, the transformation of clay minerals is considered to be another main siliceous source. The Shanxi Formation microscopically has features of pressure dissolution. In combination with the cathodoluminescence features of the quartz, it is held that there exists the siliceous source of pressure dissolution, which, however, is not the main source. On the basis of the microscopic pressure solution in underlying Shanxi Formation and the cathodoluminescence features of quartz, the pressure solution is thought to serve as a minor siliceous source. The advection flow and the diffusion migration in the reservoir made up the main migration pattern for the silicon derived from the dissolution of feldspar and the transformation of clay minerals, whereas the silicon derived from the pressure solution migrated to pores by chemical potential between particles and pores and precipitated at the grain surface or moved in the mixed source. The change of pH resulting from the invasion of acid fluids was the main factor controlling silicon deposition, while the temperature, pressure and oil-gas filling had little effects and the wrapping action of clay minerals on the grain surface had no effects on quartz deposition.

Abstract:The impact of microbes on lithosphere starts with the change of minerals comprising rocks, whereas the impact of microbes on minerals starts with the change of the composition of minerals. Based on previous researches on the interaction between microbes and minerals, this paper studied the interaction between silicate bacteria Bacillus mucilaginosus and bentonite, which is mainly composed of layer silicate montmorillonite and a small amount of other silicate minerals such as quartz and feldspar, and analyzed the impact of microbes on betonite in such aspects as composition and microstructure. The concentrations of elements Si, Al and Mg in solution were tested by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), after being treated by hydrogen peroxide. The minerals after bacteria dissolution were analyzed by X-ray Diffraction (XRD) and Micro-Fourier Transform Infrared Spectroscopy (Micro-FTIR).The pH values of the reaction solution rapidly decreased from 7.5 to 4.3 in the first 2 days. Then the pH values became gradually stabilizing. The dissolution quantities of Si, Al and Mg from the mineral crystal lattice were unbalanced. The X-ray diffraction patterns (XRD) showed that the phase of calcite (Ca) disappeared in bacteria dissolution products (BM), which was probably caused by acid metabolic products of bacteria, and there was a new faint diffraction peak that appeared between 9° to 10° in the samples treated by bacteria. According to the Micro-FTIR spectra, the absorption peaks at 3620 and 3400 cm-1 shifted to higher wavenumber and the intensity decreased, and the intensity of weak absorption peak at 1635 cm-1 decreased too, suggesting that the content of ions in montmorillonite was changed. The disappearance of CO2-3 band absorption peak at 1434 and 880 cm-1 was consistent with the XRD result of the disappearance of calcite phase.Through analyzing pH changes in solution, variations of major elements in solution and minerals, and structural, infrared spectroscopic and specific surface area changes, the authors inferred that the bacteria dissolution process is like this: first, acidic metabolites produced during the growth of bacteria and contact interaction between minerals and bacteria dissolve the vulnerable parts of mineral surface, and some cations in mineral structure are dissolved. With the dissolution, the uneven exsolution of cations may cause the change of mineral grains surface and even the collapse of the silicate layer, and the mineral structure is changed at last.

Abstract:Scanning electron microscopy equipped with energy dispersive X-ray detector (SEM-EDX) was used to study the atmospheric dust fall aerosols collected in Lhasa under the regular meteorological conditions in summer. The results offer the particles size, mineral composition and mineral morphology of the atmospheric dust fall in Lhasa. Morphologic observation of SEM reveals that the dust falls are mainly composed of clay silicate particles in the irregular flaky shape and a certain amount of such anthropologic and biological particles as soot and pollens. On the basis of EDX analyses of 149 particles and by using the developed elemental weight method, the authors classified the particles into six different categories, i.e., atmospheric particles mainly composed of “Si-rich" particles, “Ca-rich" particles, “Fe-rich" particles, “C-rich" particles (fly ash particles from coal and oil combustion), “K-rich" particles and “Zr-rich" particles. Statistics of the particle quantity show that silicates possess 52.4% of total particles. The silicate particles in the sample include much more felsic components than mafic (Fe-Mg-rich ) particles, and the felsic particles are mainly distributed in four subgroups, namely, “quartz group", “orthoclase group", “pyrophyllite and montmorillonite group" and “muscovite and illite group"， with the mafic particles mainly distributed in the “biotite and vermiculite group". “Ca-rich" particles were detected in 28.2% of the particles, and most of Ca components are “high-Ca" particles and exist as calcite (CaCO3). A study of the mixture state of Ca in atmospheric particles shows that particles with weight ratio of Ca, P(Ca), greater than 0.1 and 0.02possess 47.3% and 86.8%, respectively, and 26.5% of the particles are Ca-dominant particles with P (Ca) ≥0.65. Particles with Ca are concentrated in the radius range of <5 μm，and most of the Ca is internal mixture in silicate particles. Sufficient attention should be paid to fuel carbonaceous particles from vehicle exhaust in emission reduction and control. The mineral composition and morphology of atmospheric dust fall act as important criteria in identifying pollution sources.

Abstract:A set of organic bentonite preparation means different from traditional technology was proposed, and the COD (chemical oxygen demand) and XRD (X-ray diffraction) double indicators were used for the first time to measure the synthetic effect of organic bentonite. COD tests showed that the selection of the appropriate type and the amount of modifier made up two prerequisites for preparing organic bentonite used in organic wastewater treatment. As two kinds of modifiers, both solid di-octadecyl dimethyl ammonium chloride from Shanxi and solid esterquat from Henan were suitable for preparing organic bentonite used in organic wastewater treatment. XRD analysis demonstrated that the d001 value of montmorillonite mineral was increased from 1.251 nm to 3.373 nm after the modification of bentonite by di-octadecyl dimethyl ammonium chloride, whereas the d001 value of montmorillonite mineral was increased from 1.251 nm to 5.103 nm through the modification by esterquat. The d001 value of montmorillonite in the new preparation process of organic bentonite increased significantly, and long-chain molecules of organic modifier had been inserted between layers of montmorillonite minerals, which indicated that the synthetic effect was good. The new synthesis process of organic bentonite can eliminate the need for filtering, washing, drying, grinding and other steps, thus significantly reducing energy consumption and production cost, and can also effectively promote the larg-scale application of organic bentonite in the field of wastewater treatment.

Abstract:This paper deals with a weathering profile of carbonate-type tailings (sulfide-bearing carbonate-rich tailings) in Bali tailings storage of the Dahang tin-polymetallic orefield in Guangxi. The storage was closed about 20 years ago. Based on studying the profile using composite geological-geochemical methods such as investigation of fabrics and contents, XRD analysis, Sobek-ABA and NAG test, the authors have reached the following conclusions: ① oxidation of tailings increased from bottom to top of the profile, associated with gradually increasing acidity of tailings, resulting in a layering (zoning) structure: C layer at the bottom was a reduction and primary zone (incoherent tailings without alteration); B layer in middle profile was a suboxidation and base-buffer zone (incoherent tailings with partial alteration); A layer at the top was a oxidization and acidification zone (coherent hardpan, 1～1.5 m in thickness). An acidic-base buffer interface was located between A layer and B layer, higher than the oxidation-reduction interface at the bottom of B layer. ② Acidic-base buffering occurred in B layer, and the base materials were mainly derived from calcite. ③ Neutral efficiency (or real-consumption rate) of carbonate (CaCO3) was about 80%. These phenomena might be attributed to the following reasons: the armor formed by secondary minerals such as lepidocrocite and gypsum during the acidification of tailings caused the development of the rest of carbonate particles and then blocked the neutral reaction of carbonate in tailings. Therefore, it is inferred that the metal-sulfide tailings, even if containing excessive carbonate (base materials), still possess a potential of acidifying and generating acid mine drainage.

Abstract:Macroscopic and microcosmic observations of the plagioclases from plagioclasite of southern Finland indicate that the plagioclases with parallel needle-like inclusions has iridescence, while the plagioclases without inclusions do not have iridescence. The inclusions can be divided into two types based on their degrees of development. Dense-type inclusions are 35～50 stripes/mm with 0.01～0.03 mm in length and 0.004 mm in width, while sparse-type inclusions are 25～35 stripes/mm with 0.005～0.015 mm in length and also 0.004 mm in width. The plagioclases with dense-type inclusions are mainly blue while the sparse-type inclusions are orange and red in color. A compositional analysis by means of scanning electron microscope, electron microprobe and laser Raman spectrometry shows that the inclusions are magnetite in composition, and the plagioclases with or without inclusions have the same composition. It is suggested that the composition of the plagioclase and inclusions and the twin of the plagioclases are not the causes for the iridescence of the plagioclases, and the parallel distribution of the needle-like opaque inclusions in the plagioclase seems to be the factor responsible for the iridescent plagioclase. The needle-like parallel inclusions in plagioclases resemble the grating in physics. The iridescence of the plagioclase is probably generated by the diffraction and interference of the light.