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The Longbohe Cu deposit, which is located in the southern part of the Honghe ore-forming zone, Yunnan Province, China, belongs to a typical ore field where volcanic rocks are of wide distribution and are associated with Cu mineralization in time and space. The volcanic rocks in the ore field, which have experienced varying degree of alteration or regional metamorphism, can be divided into three types, i.e., meta-andesite, meta-subvolcanic rock and meta-basic volcanic rock in accordance with their mineral asemblages. These three types of volcanic rocks in the ore field are relatively rich in Na and the main samples plot in the area of alkali basalts in the geochemical classification diagram. With the exception of very few elements, these three types of volcanic rocks are similar in the content of trace elements. In comparison to the basalts of different tectonic settings, the meta-volcanic rocks in the ore field are rich in high field strength elements (HFSE) such as Th, Nb, etc. and depleted in large ion lithophile elements (LILE) such as Sr, Ba, etc. and their primary mantle-normalized trace element patterns show remarkable negative Th and Nb anomalies and negative Sr and Ba anomalies. These three types of volcanic rocks are similar in REE content range and chondrite-normalized REE patterns with the exception of Eu anomaly. Various lines of evidence show that these three types of volcanic rocks in the ore field have the same source but are the products of different stages of magmatic evolution, their original magma is a product of partial melting of the metasomatically enriched mantle in the tensional tectonic setting within the continent plate, and the crystallization differentiation plays an important role in the process of magmatic evolution. [ABSTRACT FROM AUTHOR]

Soluble organic matter had been separated from several palygorskite and bentonite samples in the Jiangsu-Anhui border area (across Jiangsu Province and Anhui Province) and Linze County in Gansu Province of China and was analyzed with the techniques and methods of organic geochemistry. The composition and distribution of hydrocarbons were analyzed by gas chromatography (GC). Organic stable carbon isotopic ratios (δC) in typical samples were determined. The abundance of soluble organic matter in all clay samples analyzed was low. In Jiangsu-Anhui samples, the preservation states of organic matter are different; hydrocarbons in organic matter have some features of aquatic plankton but are short of the input of terrigenous higher plants; organic δC in a palygorskite of Yongxiaoshan in Xuyi County, Jiangsu Province, is −6.72‰. These features may be typical of a sedimentary environment of closed or semi-closed and relatively isolated different waters near coast or seashore. On the contrary, in samples from Gansu, the preservation states of organic matter are good; the GC graphs of hydrocarbons show that the precursors of the organic matter are from a mixed source of aquatic organisms and land-sourced higher plants; organic δC of a palygorskite from Yangtai of Gansu is −15.62‰. It indicated that the sedimentary environment may be an inland salty lake. Preliminary results suggest that palygorskite minerals in the Jiangsu-Anhui area may be evolved from rapidly accumulated fine material or volcanic ash, but clays in Gansu Province may be transformed from terrigenous inorganic clastic components carried to the lake through river and then deposited. The generation process of the samples studied in the paper seems to be related to salty water. [ABSTRACT FROM AUTHOR]

The Huangshui River, an important tributary in the upper reaches of the Yellow River, has been regarded as a mother river which gestates Qinghai civilization in China. This paper presents the results of hydrogen and oxygen isotopic and water chemical analyses for the summer and winter Huangshui River water to study its seasonal recharge and major dissolved solutes. Characteristics of hydrogen and oxygen isotopes suggest that precipitation in the Qilian Mountains is the original recharge of the Huangshui River. However, in winter, the basic flow of the Huangshui River only depends on spring recharge and spring water originates from melt and infiltration of bottom layer glaciers. In summer, besides spring water, much rainfall directly recharges the Huangshui River, thus making its flux increase greatly. Water chemistry shows that the processes affecting dissolved solutes in the Huangshui River are also different between summer and winter. In summer, major ions in the river water are dominantly derived from carbonate and evaporate dissolution and anthropogenic inputs. In winter, carbonate dissolution decreases greatly while anthropogenic inputs play a much more important role for dissolved solutes in the river. Hence, further measures should be taken to lay stress on the winter Huangshui River water in order to protect the environment of the Huangshui River and reduce effects of dissolved solutes on, or prevent their pollution toward the upper Yellow River. Moreover, some measures also need to be introduced to prevent the possibility of water eutrophication caused by agricultural activities or stock raising in summer. [ABSTRACT FROM AUTHOR]

Geochemical studies on REE, trace elements and oxygen isotopes from metamorphic veins and their host metasedimentary rocks in the Zhoutan Group at two localities, Xiangshan and Yihuang, in central Jiangxi Province have been conducted in this paper. The results show that the metamorphic quartz veins inherited the REE and oxygen isotope geochemical characteristics from their host rocks, suggesting that the vein-forming fluids were derived from the host rocks. Additionally, fractionation degrees of the trace element pairs Zr-Hf, Nb-Ta, Y-Ho and U-Th in the veins are different from those of their host rocks. It is also indicated that the veins are the products of the fluids. The metamorphic veins within the Zhoutan Group metasedimentary rocks were formed principally as a result of lateral diffusion of the metamorphic fluids. [ABSTRACT FROM AUTHOR]

Marine strata are widely exposed in the Hushan and Chaohu areas, Lower Yangtze region. As biomarker geochemistry of the strata has not been well documented, this paper deals with the biomarker composition of representative samples collected from the Silurian, Carboniferous and Triassic systems and their geological implications, thus providing clues to marine organic matter. On the basis of experimental results, it is shown that abundant biomarkers (e.g. n-alkanes, isoprenoids, terpanes and steranes) were detected. As organic matter in the strata is highly to over mature in general based on petrologic microobservation, some biomarkers (mainly n-alkanes) except terpanes and steranes cannot reflect the source, depositional environment and maturity of organic matter. Thus, primarily based on analyses of the terpanes and steranes, it is suggested that organic matter in the Silurian and Carboniferous strata is derived mainly from lower organisms, while higher plants are predominant in the Triassic organic matter. This further indicates that the depositional environment may have transformed from the marine to continental facies in the Late Triassic. These results provide new evidence for the study of regional depositional evolution, and have enriched the study of biological composition of organic matter. In addition, the biomarker geochemistry of organic matter at high to over maturation stage is addressed. [ABSTRACT FROM AUTHOR]

The Baimazhai nickel deposit, Yunnan Province, China, is located in the southern part of the Sanjiang (Tri-river) alkali-rich intrusive rock belt (Sanjiang ARIR). In this paper was conducted 40Ar-39Ar dating of two phlogopites in lamprophyres which are, as dikes, widely distributed in the orefield, and two plateau ages were acquired, i.e., 32.46±0.62 Ma and 32.01±0.60 Ma, respectively (averaging 32.23±0.60 Ma). The ages are obviously younger than those of the ore-hosted complex and mineralization of the Baimazhai nickel deposit. In combination with the characteristics, it is indicated that lamprophyres in the orefield and those in the Sanjiang ARIR are similar in tectonic setting, mineral assemblage and geochemistry. It is considered that lamprophyres in the orefield are the important component of the Sanjiang ARIR, and the lamprophyres and ore-hosted complex in the orefield represent the products of two times of different magmatic activity from different mantle sources. On the other hand, the age of lamprophyres in the orefield is older than that of the strike-slip shearing of the Ailaoshan-Honghe fault belt, suggesting that the strike-slip shearing of the Ailaoshan-Honghe fault belt is not the factor leading to magmatic activity of lamprophyres in the orefield, while it is more possible that magmatic activity of the Sanjiang ARIR promoted strike-slip shearing of the fault belt. [ABSTRACT FROM AUTHOR]

In the future time the exploration of marine oil and gas will be one of the significant domains in China. In this paper the biomarker assemblage characteristics of oilshow in the Nanlinghu Formation of the Majiashan profile, which is located in Chaoxian County, south of Anhui Province, are described in the light of gas chromatography/mass spectrometric (GCMS) analysis on the qualitative and quantitative basis. Based on the investigation of the biomarker assemblage characteristics of possible source rocks developed in the area studied, a conclusion is drawn that the oilshow was generated from the Nanlinghu Formation source rocks (abbreviated as T1 n), instead of the Qixia Formation source rocks (abbreviated as P1 q). It is pointed out that the T1 n is of strong potential for future oil exploration, and therefore much attention should be paid to it. [ABSTRACT FROM AUTHOR]

This paper describes the environmentally geochemical characteristics of heavy metal pollutants such as Cu and Zn in the surficial soil of Guiyang, the capital city of Guizhou Province. The baseline concentrations of heavy metals in soil and the geochemical norms have been established to distinguish natural or artificial influence on the environment. Using the statistically analytical methods, we have established the baseline of Cu in Guiyang (18.8 mg/kg) and the soil (over 68.4 mg/kg) may suffer Cu contamination. The data of Zn are 46.3 mg/kg and 112.0 mg/kg. Geoaccumulation index analysis indicated that the surficial soil that has suffered non-pollution to mid-pollution of Cu accounts for 38%, 38%, and 22% for mid-pollution, arid only 2% between mid-pollution to severe pollution. Surficial soil that has suffered non-pollution Io mid-pollution of Zn at counts for 41%, 50%, and 7% for mid-pollution, and only 2% between mid pollution to severe pollution. The maximal degree of Cu contamination is 5.09 in the surficial soil of Guiyang. Surficial soil that has not suffered Cu pollution accounts for 53.2%. The total pollution degree of Cu is slightly over zero. So the surficial soil of Guiyang has suffered slight Cu pollution. The maximum value of Zn contamination degree is 2.85 in the surficial soil of Guiyang. 77.8% of the surficial soil has not yet suffered any Zn pollution. The total pollution degree of Zn is less than zero. So the surficial soil in Guiyang is free from pollution of Zn. [ABSTRACT FROM AUTHOR]

The Huize large-sized Pb-Zn deposit in Yunnan Province, China, is characterized by favorable metallogenic background and particular geological settings. This suggested that the ore-forming mechanism is relatively unique. On the basis of geological features such as the contents of mineralization elements, the REE concentrations of gangue calcites, the REE concentrations of calcite veins in the NE-trending tectonic zone and the Pb, Sr, C, H and 0 isotopic compositions of different minerals, this paper presents that the ore-forming materials and ore-forming fluids of the deposit were derived from various types of strata or rocks. This is a very significant conclusion for us to further discuss the mineralization mechanism of the deposit at depth and establish an available genetic model. [ABSTRACT FROM AUTHOR]

More and more evidence indicates that organic matter (OM) in immature organic-rich sediments and sedimentary rocks is chemically adsorbed onto the outer surfaces of minerals and into interlayer (inner) surfaces of smectitic clay minerals in the form of amorphous molecular-scale carbon. But there have been few reports about the occurrence of highly mature OM in marine black shales (petroleum source rocks). The occurrence of highly mature OM in the black shales of basal Cambrian from northern Tarim Basin is studied in this paper. Based on the comprehensive analyses of total organic carbon contents (TOC) , maximum thermoplastics temperatures (Tmax) of OM, mineral surface areas ( MSA ) , and scanning electronic microscopic (SEM) and transmission electronic microscopic (TEM) observations of the black shales, it is concluded that the highly mature OM in the marine black shales of the basal Cambrian from northern Tarim Basin occurs in particulates ranging In size from 1 to 5µm in diameter. Through the contrast of the occurrence of the highly mature OM in the black shales with that of the immature ones in modem marine continental margin sediments, some scientific problems are proposed, which are worth to study further in detail. [ABSTRACT FROM AUTHOR]

Well Zheng-1 is located in the combined area of the central uplift and the north Tianshan piedmont depression in the Junggar Basin. Two oil-bearing beds are recognized at 4788–4797 m of the Lower Cretaceous Tugulu Formation (K1tg) and 4808.5–4812.5 m of the Lower Jurassic Sangonghe Formation (J1s). The geochemical characteristics of family composition, carbon isotopic composition, saturated hydrocarbons, sterane and terpane biomarkers and carotane of two crude oils are described in this paper. The results show that the geochemical characteristics of the two crude oils are basically similar to each other, indicating they were all derived mainly from the high mature, brine, algae-rich lake facies sediments. Oil-source correlation revealed that crude oils of the two beds were derived mainly from the source rocks of Permian and mixed by the oil derived from the source rocks of Jurassic and Triassic. This is consistent with the geological background with several sets of source rocks in the area studied. [ABSTRACT FROM AUTHOR]

The Yangtze Valley was one of the most important metallogenic regions during the Jurassic-Cretaceous period in East China, where more than 200 polymetallic Cu-Fe-Au, Mo, Zn, Pb, Ag deposits have been found. Trace elements were chemically analyzed and the relevant data were collected from literature for the Yanshanian (Mesozoic) igneous rocks which have close relationship with Cu-Au mineralization. Copper mineralization in the lower Yangtze Valley can be divided into three major types: skarn type, porphyry type and volcanic type. The porphyry type is of rare occurrence, such as the Shaxi porphyry copper deposit in the northern part of the lower Yangtze metallogenic valley. This paper focuses on the REE and trace element geochemistry of several Cu-Au deposits along the lower part of Yangtze metallogenic valley in Anhui. The results showed that there are differences in REE distribution for these four types of Cu-Au mineralization, which confine the sources of REE and trace elements as well as other mantle and transitional compatible elements. The results of both REE and trace element geochemical studies showed that these elements with different characteristics have different origins, probably representing different sources of Cu-Au deposits in the deep crust and upper mantle environments. The 40Ar/39Ar dating of one biotite sample gave an age of 131 Ma with a high level of confidence, which represents the age of formation of the Shaxi porphyrite intrusive with porphrytic Cu-Au mineralization, which is consistent with that of the majority of the adjacent acid intrusives with mass Cu-Au mineralization along the Yangtze metallogenic belt in the Yanshanian period (Mesozoic). This is the first attempt to use the high precision method to date the Shaxi porphyrite intrusive. [ABSTRACT FROM AUTHOR]

Due to the rapid development of modern science and technology, many advanced sensors have been put into use to explore our solar system, including the Moon. With the help of those detectors, we can retrieve more information to about the Moon's composition and evolution. The Clementine (January, 1994), Lunar Prospector (January, 1998) and especially Smart-1 (September, 2003) launched successively have demonstrated the next-generation planet exploration techniques. Now China has decided to send a probe to the Moon. So it is necessary to overview the development of detectors used for the scientific observation of the Moon. In this paper, some main instruments used to acquire geochemistry information are described, which include UV-VIS-NIR CCD imaging spectroscope, neutronray, gamma-ray, and X-ray spectrometers. Moreover, the payloads of China's first lunar satellite are introduced briefly. [ABSTRACT FROM AUTHOR]

This paper deals with the meta-mafic volcanic rocks of the Gongyiming iron deposit at Baotou, Inner Mongolia. The major and trace elements and REE data indicate that the meta-mafic volcanic rocks occurred in the environment similar to a modern continental rift. Sm-Nd and Rb-Sr isotopic studies indicated that the meta-basic rocks were formed during the Early Neoarchean from 2800 Ma to 2900 Ma and reworked during the Late Neoarchean (2500 Ma) by metamorphism. Because of the separation of the North China Craton from the Siberia Craton during the Middle Proterozoic (1600 Ma), the Rb-Sr systematics of the rocks has been changed. The Se' ertengshan greenstone seems to occur during the Middle Archean. A stable continental crust may have existed during the Paleoarchean. [ABSTRACT FROM AUTHOR]

This paper deals with the high-K, potassic dike rocks in two types of gold ore fields at Linglong and Dayigezhuang, Northwest Jiaodong. The rocks can be divided into three types, i.e., (1) lamprophyre, (2) andesite porphyrite, and (3) dacite porphyrite, based on their geological occurrence and space-time relationship with gold mineralization. These rocks were the products of early, synchronous and late mineralization, respectively. Element geochemistry shows that variations in chemical composition of major oxides follow the general rules of magmatic fractional crystallization. The fractional crystallization of mineral phases of augite in the early state (namely in the lamprophyre stage) and hornblende and plagioclase in the late stage (namely from the andesite-porphyrite to dacite porphyrite stage) controlled the magma evolution. The rocks are enriched in alkali and have higher K[sub 2]O and lower TiO[sub 2] contents, as well as strongly enriched in large ion lithophile elements such as Ba, Sr and Rb, and LREE but strongly depleted in transition elements such as Cr and Ni. Rb is depleted relative to Sr and Ba, and RB/Sr ratios are low. Volatile constituents are abundant. These characteristics indicate thin the initial magma originated from the metamorphic subduction ocean-crust that had been intensively contaminated by crustal materials, and retrogressive metamorphism is characterized by low-degree partial melting during back-arc spreading. Varying degrees of partial melting and different emplacement environments may be the main causes for the evolution of the rocks and mineralization in different degrees in the two gold ore fields at Linglong and Dayigezhuang, Shandong. [ABSTRACT FROM AUTHOR]

Fluid inclusion studies of 5 gold deposits connected with alkaline rocks show that quartz separated from auriferous quartz veins contains abundant three-phase CO[sub 2]-NaCl-H[sub 2]O inclusions and two-phase CO[sub 2]-dominated ones, measuring 5 - 20μm in diameter. Homogenization temperatures of the fluid inclusions are mostly within the range of 150 - 300°C, and the salinities, mainly 0.2wt& - 12 wt% (NaCl). Gold mineralizations occurred at depths of 1.4 - 2.8 km. The most striking character of fluid composition is that among the cations, Na[sup +] is dominant, followed by K[sup +], Ca[sup 2+]; among the anions, Cl[sup -] is slightly higher than SO[sup 2][sub 4]. In the evaporate, H[sub 2]O is dominant, followed by CO[sub 2]. The pH values are mainly within the range of 6.5 - 8.5, indicating that the ore-forming solutions are alkaline in nature. The hydrogen and oxygen isotopic ratios indicate that the ore fluid is composed mainly of magmatic water. With the dropping of temperature in the ore fluid, the contents of CO[sub 2] decreased while the salinity increased. The relations between Au and other components of the ore fluid are discussed in the paper, and it is concluded that in these deposits, chlorides, H[sub 2]S, SiO[sub 2], CO[sub 2], etc. in the fluid all are involved in the migration and concentration of Au. [ABSTRACT FROM AUTHOR]

Based on the analysis and study of mineral composition, structure, and major and trace elements, this paper deals with element geochemical characteristics and transformation from primary ore into oxidized ore in the Erzhe gold deposit, Sichuan. Some grounds are provided to constrain the transformation of primary ore to oxidized ore. [ABSTRACT FROM AUTHOR]

Discriminations in a local chemical, fluidal, mechanical and thermal processes in a shear zone will lead to metallogenic differentiation in a local section. This paper, based on the general geological setting of the Shibangou gold deposit in Xixia, Henan, deals with petrological and petrohemical samples of altered rocks in the metallogenic section and of mylonites in the non-metallogenic section of a selected shear zone. The discriminations in fluid-rock interaction and petrological mass balance between altered rocks near the orebody and mylonites in the shear zone are discussed as well. The results show that the petrological volume of altered rocks in the metallogenic section of the shear zone is almost always dilatant and the mylonite volume in the non-metallogenic section is almost always lost. Major elements in altered rocks from the metallogenic section and in mylonites from the non-metallogenic section always show a tendency of being enriched and depleted, respectively. Fluid-rock ratios in the mylonites (Nu = 93.68-468.40) are larger than those of the altered rocks (Nc³[sub (IV)] = 36.11-216. 67). The gain and loss of major and trace elements from the altered rocks and mylonites in the shear zone are a composite process to be imported and exported by percolating fluids as well as of the loss and dilatancy of rock vo1ume. [ABSTRACT FROM AUTHOR]

Tar mats were firstly discovered and determined accurately in terrestrial oil and gas reservoirs associated with Lower Tertiary sandstone reservoirs in the Yaha field of the Tarim Basin, China, by thin-layer chromatography-flame ionization detector (TLC-FID) and Rock-Eval analysis. The relative content of asphaltene in gross composition of tar mat extracts accounts for more than 30%, that in the corresponding oil leg less than 20%. In the geochemical description profile of oil and gas reservoirs, drastic changes in asphaltene contents between tar mats and oil legs could be discovered. This is an important marker to determine tar mats. Distribution characteristics of saturated and aromatic hydrocarbons from reservoir core extracts and crude oils in the Yaha oil and gas reservoirs in the Tarim Basin are described systematically in this paper, and the results show there are similarities among n-alkane distribution characteristics, biomarker distribution characteristics and their combined characteristics of saturated hydrocarbons, and the geochemical characteristics of aromatic hydrocarbons for tar mats, oil leg, asphaltic sand and crude oil. These characteristics suggest the hydrocarbons in these samples were originated from the common source rocks. However, the geochemical characteristics of tar mats revealed that the mechanism of formation of tar mats is the precipitation of asphaltene from crude oils in petroleum reservoirs caused by increased dissolved gas in oil legs (gas injection). [ABSTRACT FROM AUTHOR]

Many studies have been conducted on heavy metal concentrations in urban outdoor dust in China, showing that differences exist in the metal concentrations of different cities. However, no report has studied the distribution of heavy metals across Chinese cities. This work presents the spatial distribution of heavy metals in urban outdoor dust in Chinese cities and discusses the causes for the differences in heavy metal levels across cities by analyzing and summarizing data for 20 provincial capitals from the published scientific literature. The results show that the geometric mean values of Ni and Cr in urban dust of China are lower than or comparable to crustal levels, whereas levels of Cd, Cu, Pb, and Zn are significantly greater than crustal levels. The spatial distributions of Cu, Pb, and Zn in urban dust all exhibit a pattern in which heavy metal levels are greater in cities located in the south of China than in the north. Commercial areas and residential-education areas accumulate more Cd in their dust than industrial areas and traffic areas, and industrial areas and residential-education areas accumulate more Pb than commercial areas and traffic areas. The Zn level in dust from industrial areas is significantly greater than in other areas, and Cu exhibits no significant difference between different functional areas. A positive correlation exists between Cd and Zn in urban dust and population density. Urban dust Pb in Chinese cities is lower than the world average as calculated using data for thirteen cities in different countries. Cd, Cu, and Zn levels in China are close to world averages. [ABSTRACT FROM AUTHOR]

Trace elements of the No. 9 coal seam from Aanjialing mine were measured by ICP-MS. The results indicated that Li, Ga, Cr, Sr, Zr and Pb are significantly enriched in the No. 9 coal seam. The Li and Ga contents in most of the coal seam samples reached an economically valuable level. Most trace elements were enriched near the roof and floor. The data from the Sr/Ba, V/Zn, Th/U, V/Zr and V/Ni ratios reveal that during this period, the peat swamp from this area was formed in swamp water, which was influenced by sea-water or, in an sea-land transition environment, where the ancient water salinity was slightly high. The Eu negative anomaly obviously shows that the rare earth elements are consistent with the terrigenous rocks, so we deduced that the rare earth elements contained in the mineral may mainly come from terrestrial detritus. [ABSTRACT FROM AUTHOR]

Ten representative limestone samples [six from Wangshan Formation (WL) and the other four from Gouhou Formation (GL)] were collected from outcrops of the northern Anhui Province, and REE concentrations in limestone were measured by ICP-MS. The depositional environment and source of the REE were analyzed, and the results implys that the total REE of samples are low compared with the recent marine sediments, which range from 9.61 to 54.18 mg/kg and an average of 22.93 mg/kg. The PAAS-normalized REE+Y patterns of limestone are characterized by (1) light REE depletion in WL and enrichment in GL with the values of (Nd/Yb) ranging form 0.65 to 0.91 and 1.12 to 1.46, respectively; (2) light negative Ce anomaly (0.85-1.02) and positive La anomaly (0.92-1.27); and (3) both Eu (0.91-1.23) and Y (1.42-2.38) expressing light positive anomaly. The character indicated that the depositional environment was oxygenated, with infection by the hydrothermal activity and contamination of detritus. [ABSTRACT FROM AUTHOR]

Terrestrial faulted lacustrine basin is considered as a favorable place for the development of source rocks, especially the fault basins in eastern China. Based on molecular composition study of saturated and aromatic hydrocarbons in the extracts of source rocks of the Yingcheng and Shahezi formations in the Lishu Fault Depression, it is revealed that the extracts of source rocks are provided with low ratio of Pr/Ph, low content of C tetracyclic terpanes, high content of tricyclic terpanes and gammacerane, relatively high content of C steranes in the sag belt and its periphery; relatively high ratio of Pr/Ph, relatively high content of tetracyclic terpanes and gammacerane, low content of C steranes and obvious advantages of C steranes in its gentle slope belt; with high ratio of Pr/Ph, high content of C, C tricyclic and C tetracyclic terpanes, very low content of gammacerane and C steranes, and high content of C steranes in the edge of fault depression. According to the organic matter input and sedimentary environment, three types of source rocks have been established, which, respectively, are the mode of mixing organic matter input in deep and semi-deep lake, the advantage of terrigenous input in shallow lake and terrigenous input in shore-shallow lacustrine. The first mode is supposed to generate oil and gas, while the second one tends to generate oil. The distribution characteristics of oil and gas in the Lishu Fault Depression are very likely to be controlled by hydrocarbon generating characteristic of different source rock types. [ABSTRACT FROM AUTHOR]

Inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectroscopy, hydride generation-atomic fluorescence spectrometry, emission spectrometry, X fluorescence spectrometry, and X-ray diffraction were employed to study the geochemistry and mineralogy of coal gangues from Nos. 2, 3, and 8 coal seams of the Du'erping coal mine, Xishan coalfield, Taiyuan, Shanxi Province. The study revealed that compared with the sedimentary cover, upper continent crust, Carboniferous-Permian coal from North China, as well as most coal in China, coal gangues from Nos. 2 and 3 coal seams are rich in Li, Be, Sc, Cr, Cu, Ga, Ba, Th, Nb, Cd, Pb, Ta and rare-earth elements, and coal gangues from No. 8 coal seam are rich in Li, Sc, V, Cr, Ga, U, and rare-earth elements. Compared with the Carboniferous-Permian coal from North China and most coal in China, coal gangues from Nos. 2, 3 and 8 seams are rich in Rb, V, Cs and Sr. Therefore, The Du'erping coal gangues in the Xishan coalfield are rich in most hazardous trace elements and rare-earth elements, wherein the contents of Ga and Li reach the industrial grade and have significance for industrial utilization. On the whole, coal gangues of the Shanxi Formation from the Permian are rich in more trace elements than those of the Carboniferous Taiyuan Formation. The distributions of REE show obviously dipping rightwards with negative Eu anomalies. The contents of rare-earth elements in the three seams are quite different. All of the above indicate that the source of the rare-earth elements is terrigenous debris. Minerals in No. 2 seam identified by X-ray diffraction mainly include quartz, kaolinite, in addition to calcite, pyrite, apatite, epidote, and epsomite. No. 3 seam mainly contains quartz, kaolinite, in addition to a small amount of sodium feldspar, calcium nitrate, iron ore, gypsum, and vivianite. No. 8 seam mainly contains kaolinite, dickite, quartz, illite, and a small amount of hematite and U. The correlations between major elements and trace elements in coal gangues of the Du'erping coal mine analyzed by using SPSS (Statistical Product and Service Solutions) indicate that the trace alkali elements and rare-earth elements occur mainly in such clay minerals as kaolinite. [ABSTRACT FROM AUTHOR]

Recently discovered intermediate-basic volcanic rocks in the Devonian strata at Dachang, Guangxi Zhuang Autonomous Region are dominated by basalts and andesites. Most of them belong to the calc-alkali and alkali series. Petrology and geochemistry data indicate that the volcanic rocks may be formed in a continental rift environment. The volcanic rocks are in conformable contact with the overlying and underlying wall rocks, with such typical sedimentary structures as laminated and striped ones, and the host rocks of the volcanic rocks contain lots of marine fossils such as tentaculite. Many pieces of evidence indicate that the eruption environment of the volcanic rocks is a sea-facies one. The volcanic rocks are of the LREE-enrichment type, with high ratios of light rare-earth elements to heavy rare-earth elements. In addition, they display moderately negative δEu anomalies and moderately negative δCe anomalies with a higher degree of LREE and HREE fractionation. Through the Q-cluster analysis of the REE samples, it is indicated that the ores have a closer relation with the layered volcanic rocks, and also possess a certain inheritance-consistency relationship with the layered volcanic rocks. The source of ore-forming materials may be related with volcanism. It is proposed that the ore deposit in the study area should be genetically explained as the result of marine volcano-sedimentary exhalation of hot water and late superposition-reworking. [ABSTRACT FROM AUTHOR]

South China is one of the regions severely suffering from acid rain in the world. However, few systematic studies of rural precipitation chemistry have been performed in comparison with the extensive studies on their urban counterparts of this region. In order to characterize the current acid rain status and identify its possible sources in the rural area of South China, we analyzed precipitation collected event by event from a rural forested watershed in southern Anhui Province between March 2007 and February 2010. The results showed that the concentrations of major ions within precipitation in the studied rural area were significantly lower than those reported for the urban areas of the same latitude in China. Nevertheless, the precipitation acidity (with an average pH value of 4.49) and the frequency of acid rain (95%) were considerably high. The relatively high ratio of (SO+ NO)/(Ca+NH) was the main cause of acid rain in this rural area, as SO and NO were the main precursors of acid rain, while Ca and NH acted as the dominant neutralizers to the acidity. Source identification indicated that Ca and Mg mainly were derived from alkaline dust, SO, NO and NH originated mainly from anthropogenic sources such as industrial and agricultural activities, most Na, Cl, K and some of Mg were derived from the sea. The results suggested that the major ions within precipitation in the rural area of South China were related to the meso-scale and long-range transport of particles and aerosols in the air. [ABSTRACT FROM AUTHOR]

To study the geochemical anomaly structure of multi-element associations in the South Mining District of the Fenghuangshan Copper Mine, samples were collected and analyzed for their trace element contents. Multi-element anomaly associations were divided according to the correlations between Cu and each of the other elements, and the distribution characteristics of multi-element anomaly associations were also described. Among them, the anomaly distribution of metallogenic element Cu indicates the environment of mineralization. This study provided the basis for research on the metallogenic prediction and geochemistry of the Fenghuangshan Copper Mine. [ABSTRACT FROM AUTHOR]

The Lower Yangtze region is one of the important marine sedimentation areas of oil and gas distribution in southern China, for its favorable source rocks, reservoirs and covers. However, the intense tectonic movements and complex hydrocarbon generation process made it highly impossible to form large-sized oil and gas reservoirs. So it was divided to different hydrocarbon-bearing preservation units in oil-gas exploration. Recent study shows that the Permian and Lower Triassic source rocks in the Lower Yangtze region are complicated in lithology. The hydrocarbon generation potential of limestone there is low while argillaceous source rocks are overall of high abundance with excellent organic types, now in the process of hydrocarbon generation, so differences in high maturity influence the evaluation of organic matter abundance and type. Biomarker characteristics indicate a reductive environment. n-alkanes are marked by a single peak, with no odd-even predominance. The composition and distribution of the carbon numbers of n-alkanes, and the high abundance of long-chain tricyclic terpanes are indicative of marine sedimentation. The high contents of pregnane, homopregnane, rearranged hopane suggest that the source rocks are of high maturity. There is a good linear correlation between methylphenanthrene index and vitrinite reflectance. The correlation of oil-source rocks indicated that the oil of Well HT-3 may come from the Permian Longtan Formation in the Huangqiao area, the oil of Wells Rong-2 and Juping-1 came from the Lower Triassic Qinglong Formation in the Jurong area. The exploration here is promising in those different source rocks which all have great potential in hydrocarbon generating, and oil and gas were produced in the late stage of hydrocarbon generation. [ABSTRACT FROM AUTHOR]

The Aha Lake is a seasonal anoxic water system in the southwest of Guiyang City, Guizhou Province, China. Seasonal variations in SO concentrations and their isotopic compositions in lake water as well as in the tributaries were investigated in this study. The results showed that sulfate concentrations in river water range from 0.94 to 6.52 mmol/L and their δS values range from t14.9‰ and 0.9‰, while lake water has sulfate concentrations ranging from 1.91 to 2.79 mmol/L, and δS values from −9.8‰ to −5.9‰. It is suggested that coal mining drainage is the major source of SO in the Aha Lake. Rainfall, sewage discharge, sulfide oxidation and gypsum dissolution have made only limited contributions. Different depth-dependent distributions of dissolved SO and δS were developed for both DB and LJK in summer and winter. Due to water overturn, δS values display homogenous vertical distributions in winter and spring. While in summer and autumn, significant positive shifts of δS were clearly observed in epilimnion and bottom strata as a result of water stratification. High δS values in epilimnion may result from the retention of rainwater during water stratification. Dissimilatory sulfate reduction by bacteria was thought to be responsible for the increase of δS value in hypolimnion. [ABSTRACT FROM AUTHOR]

Tectono-geochemical samples were systematically collected from 5 drillcores along the No. 304 exploration line and at the −310 m level under the pit in the mining area, totalling 705 samples from the metamorphic rocks, granites, altered rocks and orebodies, and were determined for their contents of 20 kinds of elements including Au, Ag, As, Sb, Hg, Cu,-Pb, Zn, Sn, Bi, Mo, Co, Ni, Mn, Cr, V, Ti, Ba, Rb, Sr, etc. By using the Surfer software the geochemical exploration line profile maps for the 20 kinds of elements and the curves for the element geochemical contents of individual ore vein groups were established. In conbination with the geochemical map analytical method and Gregorian's zoning index calculation method, the vertical, longitudinal and lateral zonation sequences of the elements were ascertained and the geochemical three-dimentional zonation model of the primary halos was established on the basis of the analysis of metallogenic structures and alteration zonation. Coupled with the results of analysis of the geology and geochemistry data, it may be concluded that the process of alteration of granites in the mining area is also accompanied with the process of gold enrichment and mineralization. With the intensification of alteration of granites from granite →potash feldspathization granite →sericite-quartz alteration granite, sericite-quartz rocks →beresitized granite, pyrite sericite-quartz rock, silicified granite →gold ore, the contents of thiophile ore-forming elements such as Au, Ag, As, Cu, Bi, Mo, Pb, Sb, Hg, and Sn tended to increase. Factor analysis of trace elements indicated: factor F2 (Au, Ag, Cu, Sn, As) represents the element association brought in at the main stage of hydrothermal metallogenesis; factor F4 (Bi, Sb) and factor F5 (Pb, Zn) represent the ore-forming element association supperposed during the late stage of Au-bearing sulfides. By using the Gregorian's zoning index and map analysis method we have ascertained the primary halo axial zonation sequence (form frontal halo →tail halo): Pb, Zn, Mn, Ba, Sr, Rb, As, Sb, Ag, Cu, Sn, Mo, Au, Bi, Hg, Ti, Cr, V, Ni, and Co. The geochemical anomalies in the mining area display a tendency of lateral plunging to WS, which is consistent with the lateral plunging of orebodies and mineralization alteration zone. Comprehensive analysis of the results of investigations on ore-controlling structures, mineralization-alteration zonation and geochemical zonation of the primary halos indicates that the gold orebodies in this area are still of greater extension. [ABSTRACT FROM AUTHOR]

The karst area accounts for 61.9% of the total area in Guizhou Province, which gives rise to a fragile environment and backward economy. Comparative studies on the element contents of rock and soil and agriculture production in both carbonate area and non-carbonate area have been made to establish factors leading to low output and poor quality of agricultural products in the karst area. The result shows that there is an apparent lack of nutrient elements in carbonate rocks. The trace element contents of carbonate rocks are only 3532.27×10, but those of non-carbonate rocks are 10894.21×10. The available element contents in cultivated soil delivered from carbonate rocks are merely 101.4×10, but those from non-carbonate rocks are 326.05×10. The available element contents and total element contents in cultivated soil delivered from non-carbonate rocks are 3 times higher than those from carbonate rocks. Besides, high-quality agricultural products such as rice, potato and tea are mainly produced in the non-carbonate area. It is indicated that the low output and quality of agricultural products are caused by the above-mentioned low trace element contents and poor agricultural environment. Therefore, a new method of mineral nutrients compensation has been put forward, which is very effective to raise the load-bearing capacity of agricultural environment, agricultural output and quality of agricultural products. [ABSTRACT FROM AUTHOR]

Deep-seated cracked gas exploration was achieved great breakthrough in Es of the Minfeng area on the northern slope of the Dongying Sag. Carbon isotopic and molecular compositions studies revealed the characteristics of wet gas and a normal trend of carbon isotopic composition. Empirical cutoff points of δC and δC and light hydrocarbon compositions distinguished the cracking gas as sapropelic gas. Variations in i/ nC, i/ nC and δC further confirmed that the gas was cracked from residual kerogen. Source characteristics indicated that the gas was derived from mature-highly mature source rocks of Es with kerogen type II being dominant mixed with some oil-cracking gas. Burial history modeling indicated that there were two hydrocarbon charging periods in Es reservoirs. The first period refers to the Guantao-Minghuazhen stage dominated by oil charging, while the second period refers to the Minghuazhen stage and has been dominated by cracked gas charging till now. [ABSTRACT FROM AUTHOR]

Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the southwest of the Tarim Basin were investigated. The results showed that crude oils from the Markit Slope are divided into two oil family Classification. Oils collected from the Bashituo oilfield in the western part of the Markit Slope are characterized by high contents of tricyclic terpanes, pregnane, and homopregnane, low contents of garmmacerane (G/H<0.20), dibenzofuran, and methyl cyclohexane, and light stable carbon isotopic values (the δC values of saturated hydrocarbons and aromatic components are less than −34‰ and −32‰, respectively), with the distribution type of steranes being C≫C −32‰ and −30.6‰, respectively), with the distribution type of steranes being C>C≪C. In addition, oils from Well Qu 1 have some characteristics similar to those of the above oils, with some special characteristics including high contents of β-carotenes and special distribution of steranes (C

The Xishimen gold deposit is located in the tectonic zone southeast to the Shihu gold deposit, both of which belong to the same orefield. Then, how is the prospecting potential for the Xishimen gold deposit? A comparison was made between the Xishimen gold deposit and the Shihu gold deposit on the basis of their geological background of metallogenesis, geological characteristics of the ore deposits, the sources of ore-forming materials, etc. The results showed that both the deposits possess many similarities in the respects mentioned above. And their metallogeneses can be compared. Therefore, there is great potential for ore prospection in the periphery or at the deep levels of the Xishimen gold deposit. Ore exploration should be well programmed on the basis of a better dissection of the tectonic setting of the orefield. A breakthrough in ore prospection of the Xishimen gold deposit will be of great instructive significance in regionally geological prospecting. [ABSTRACT FROM AUTHOR]

The source of marine crude oils from Tarim Basin is still disputed. However, research on the reservoir bitumens may provide a piece of new evidence to elucidate oil source. Geochemical characteristics of reservoir bitumens from different strata from Well Zhong 1 in the Katake Uplift were discussed here in detail. Pr/Ph ratios of reservoir bitumen from Well Zhong 1 range from 1. 14 to 1. 39, CPI ratios from 1.01 to 1.08, which indicates no odd-even predominance of normal alkanes, with OEP ratios ranging from 0.98 to 1.05. The contents of gammacerane and C28 sterane of reservoir bitumen from Well Zhong 1 are low, while dibenzothiophene series are abundant. Sterane isomerization maturity parameter and Ts/(Ts+Tm) ratio indicate that the reservoir bitumen from Well Zhong1 is mature to highly mature. Based on the differences in biomarker distribution, it is concluded that reservoir bitumen from Well Zhong 1, of which molecular parameters are contrary to those in Cambrian oil from Well Tadong 2, originated from the Upper Ordovician source rocks. [ABSTRACT FROM AUTHOR]

Petrographical and geochemical studies were carried out of the Neoproterozoic carbonates from northern Anhui Province, China. These carbonates can be subdivided into two types, including purified limestone (PL) and mixed limestone and siliclastic rocks (MLS). PLs are low in Si, Al, Zr and total REE but high in CaO compared with MLSs. Correlations between Zr, FeO, PO and total REE are also less remarkable, indicating that they were not obviously contaminated by continental materials but directly precipitated from seawater. So they can be used for the inversion of paleo-seawater REE patterns. The inversed results indicated that the REE pattern of Neoproterozoic seawater was similar to that of the modern seawater except for the lack of Ce depletion, which was probably affected by the reduced hydrothermal solution. In combination with previous studies, the geochemical trending of these carbonatic samples towards the continental arc in the La-Th-Sc and Th-Sc-Zr/10 diagrams is interpreted as the contamination of arc volcanism. The tectonic background of the southern margin of the North China Craton in the Neoproterozoic was probably related to the Grenville orogeny during the convergence of the Rodinia supercontinent, rather than an intra-plate environment. [ABSTRACT FROM AUTHOR]

The age-accumulation effect of Ar in hydrocarbon source rocks was discussed in accordance with the decay law of radioactive elements. In terms of the mean values of Ar/Ar, the old Sinian gas reservoirs (mean values of Ar/Ar: 7009) were definitely distinguished from the Permian gas reservoirs (mean values of Ar/Ar: 1017) in Weiyuan, Sichuan Province, and the gas source of the Permian gas reservoir (mean values of Ar/Ar: 5222) in well Wei-7 with the Weiyuan structure is defined as the Sinian system. Based on the values of Ar/Ar, the coal-type gases (The source rocks are of the C-P system; mean values of Ar/Ar: 1125) are definitely distinguished from the oil-type gases (The source rocks are of the Tertiary system; mean values of Ar/Ar: 590) in the Tertiary reservoirs of the Zhongyuan Oilfield. Besides, Ar/Ar values also have a positive effect on the oil-source correlation of oil reservoirs in ancient hidden mountains. According to the crust-mantle interchange information reflected by He/He values, petroliferous provinces in China can be divided into three major tectonic regions. (1) The eastern active region: The crust-mantle volatile matter exchanges actively, and the He/He values are mainly around 10, partly around 10. (2) The central stable region: The He/He values are all around 10. (3) The western sub-stable region: The He/He values are mainly around 10, and around 10 on the edges of the basins. Helium contents of some gas wells in China's eastern petroliferous region reach the industrial abundance (He≈0.05%-0.1%), the He/He values reach 10, and the equivalent values for the mantle-source components in helium gas can reach 30%-50%. As viewed from this, a new type of crust-mantle composite helium resources has been proposed. Geneses of some CO gas reservoirs in the east of China and some issues concerning mantle-source methane were discussed in the light of the helium and carbon isotopes of CO and CH in natural gases. In the discussion on helium isotopic characteristics of inclusions in the reservoirs, it was discovered that the He/He values are close to those in natural gases. That is to say, this phenomenon is related to regional tectonism. The He/He, CO/He and CH/He data were used to discuss the tectonic activities of fault zones in a certain number of regions in China. [ABSTRACT FROM AUTHOR]

The origin of natural gases in central Tarim Basin is very complicated and there has been no definite conclusion in this aspect. Based on the results of systematic research on their composition and carbon isotopic characteristics, natural gases in central Tarim Basin are composed mainly of hydrocarbon gas, Ordovician natural gas with the characteristics of crude oil-cracking gas, and Carboniferous natural gas not only originating from kerogen cracking, but also from oil cracking. There are significant differences in composition and carbon isotope of natural gases between the eastern and western areas. The causes for the differences in geochemical characteristics of natural gases are presented as follows: different thermal evolution degrees of organic matter. Natural gases in the western region may have generated from the Middle-Upper Ordovician source rocks, and natural gases in the eatern region may be derived from the Cambrian source rocks, which entered into high to over mature stages; the gases migrated from west to east and caused the different compositional and carbon isotopic characteristics of natural gases; difference in the strength of thermal sulfate reduction between the eastern and western parts, with the reduction in the eastern part being stronger than that in the western part. [ABSTRACT FROM AUTHOR]

The protection system of products of geographical origin has become one hot subject with which various countries throughout the world are concerned. Results of element-Pb isotope geochemical mapping indicate that there emerge a number of famous-brand high-quality product groups of geographical origin in China. The environment of production of China's famous-brand white spirits of geographical origin at the Sichuan-Guizhou border is still a mystery to be solved. China has two main communities of white spirits of geographical origin, i.e., the most famous are Moutai and Wuliangye spirits. By element-Pb isotope geochemical tracing, we can establish the natural background geological, geographical and geochemical scientific data markers in close relation with source areas. Research on the product of geographical origin, named Kaempferia galangal L. in the Shuangjiao district, Yangchun, Guangdong Province, showed that the trace elements have an excellent heritance between Kaempferia galangal L. and soil in this area, and the trace elements are highly effective for tracing the origin. [ABSTRACT FROM AUTHOR]

292 chemical composition data and 82 isotopic composition data of gas samples collected from the Taibei Depression of the Turpan-Hami Basin, West China, were used in the study of their origin. Non-hydrocarbon gas is poor in most samples whereas abundant nitrogen in some samples is positively correlated with δ13C1. Although methane is the main constituent, higher molecular gaseous hydrocarbons, from ethane to pentane, are detected in most samples, in accordance with the distribution of oil reservoirs. The stable carbon isotope ratios of methane, ethane and propane are defined as δ13C1: −45.5‰ to −33.5‰, δ13C2: −30.2‰ to −10.5‰, and δ13C3: 27.6‰ to −11 respectively. According to the distribution of carbon isotope ratios, 2 families of gas can be grouped, most showing normal distribution of carbon isotopes, and others having obvious heavier carbon isotopes and being of abnormal distribution. Based on the isotopic composition, the disagreement between the relationship of Δ(δ13C1-δ13C2) and δ13C2 and that of δ(δ13C1-δ13C2) and δ13C2, and the calculated Ro, there are oil-associated gas, coal-derived gas and mixture of them. Other samples with obviously heavier isotopic compositions from the Yanmuxi oilfield of the Taibei Depression have been degraded by organisms. [ABSTRACT FROM AUTHOR]

Geochemical composition characteristics of light oils from the Tertiary in the west of the Chepaizi uplift in the Junggar basin, northwest China, are distinct from those of biodegraded oils derived from the Permian in the study area and crude oils from some adjacent oil fields such as the Chepaizi and Xiaoguai oilfields. Oil source correlation shows that light oils in the study area have similar n-alkane and isoprenoid distribution patterns and carbon isotope compositions with the coal-derived oils from the Jurassic, and display obvious discrepancy on biomarker composition characteristics with the Cretaceous source rock extracts, inferring that they are probably the mixed oils from the Jurassic coal measures and Cretaceous source rocks. In this study, combined with the geochemical data of coal-derived oils from the Jurassic and Cretaceous source rocks or crude oils from the Cretaceous, the source and commingling features of the Tertiary crude oils of Well Pai 2 and Well Pai 8 were investigated. The proportion of the two sources in the mixed crude oils was estimated, and the hydrocarbon accumulation pattern of reservoirs in the study area was established. [ABSTRACT FROM AUTHOR]

The zircon SHRIMP dating of the Zhangtiantang granite gave an age of 159±7 Ma., which shows that the granite was produced at the early Late Jurassic. The Ar-Ar plateau ages of biotite and K-feldspar from the Zhangtiantang pluton are 153.2±1.1 Ma and 135.8±1.2 Ma, respectively. The Ar-Ar anti-isochrone ages of biotite and K-feldspar are 152.5±1.7Ma and 135.4±2.7Ma, respectively. The ages represent the isotopic closure ages of minerals in the pluton. The Zhangtiantang granites are regarded as peraluminous crust-derived type granites to possess the typical geochemical characteristics of calc-alkaline rocks on continental margin, with enriched Si, K, Al (average value of A/CNK as 1.18), HREE, Rb, U, and Th, heavily depleted V, Cr, Co, Ni, Ti, Nb-Ta, Zr, Sr, P, and Ba, strongly negative Eu and common corundum normative (average value of C as 1.84). The εNd( t) values of the Zhangtiantang granite are −5.84 to −7.79, and t2DM values are 1.69 to 1.83 Ga, which indicates partial melting of continental-crust metamorphic sedimentary rocks during the Middle Proterozoic. The cooling history of the Zhangtiantang granitic pluton indicates that the cooling velocity of pluton was faster (about 67°C/Ma) from zircon (158 Ma) to biotite (152 Ma), and was slower (about12°C/Ma) from biotite (152.5 Ma) to K-feldspar (135.8 Ma). It can be deduced that the temporal gap (about 10 Ma) between the granite formmation and W-Sn mineralization in South China may be related to ordinary magma-hydrothermal processes by the variational cooling curve of the pluton. The Zhangtiantang pluton was formed in a compressive setting, with differentiation evolution and mineralization occurring in a relative relaxation setting. [ABSTRACT FROM AUTHOR]

The Wulong pluton was emplaced in the metamorphic complex of the Mesoproterozoic Foping Group, South Qinling. A few mafic enclaves which are rounded in shape with sharp boundaries with the host granites in the southern part of the pluton. Based on petrography, geochemistry and chronology data, it is indicated that the Wulong pluton shows some adakitic affinities with depletion in HREE (Yb=0.33–0.96 µg/g, Y=4.77–11.2 µg/g); enrichment in Sr (643–1115 µg/g) and Ba (775–1386 µg/g), high Sr/Y ratios (57.3–160) and Y/Yb ratios (11.0–14.3), and slightly negative Eu anomaly (δEu=0.70–0.83). These patterns suggest a feldspar-poor and garnet±amohibole-rich fractionation mineral assemblage. The mafic enclaves have high concentrations of Mg (MgO=4.15%–8.13%), Cr (14.8–371 µg/g), and Ni (20.0–224 µg/g), and high Nb/Ta ratios (15.42–21.9). It seems that the underplating mantle magma was responsible for the generation of the mafic magma. Companied with the results of investigations for the Qinling Orogenic Belt, it was found that partial melting of the thickened lower crust, which was triggered by the underplated mantle-derived magmas, had generated the felsic magma. The Wulong pluton provided evidence for a mixing and mingling process of two kinds of mamma. Its formation probably represents the oceanic slab breakoff during the late orogenic stage in the Qinling area. [ABSTRACT FROM AUTHOR]

The Jinding Pb-Zn deposit in Yunnan Province is the representative of a Cd-enriched area and mining activities lead to the release of Cd into the hypergenic ecosystem, resulting in Cd pollution. The concentrations of Cd vary greatly from one type to another type of rocks in the mining district. In the host rock, Cd concentrations range from 50×10−6 to 650×10−6 with an average of 310×10−6. In primary ores, Cd concentrations range from 14×10−6 to 2800×10−6 with an average of 767×10−6. However, in oxidized ores, Cd concentrations are highest, varying within the range of 110×10−6 to 8200×10−6, averaging 1661×10−6. It is shown that the oxidized ores are the main carrier and environmental source of Cd. Leaching test showed that Pb/Zn ores are easy to oxidize and thereafter release Cd and other harmful elements. These leached elements in the leachate may be precipitated rapidly in the order of Zn>Pb>Cd. As for the concentration distribution of Cd in the Bijiang River, it is estimated to be 15.7 μg/L Cd in water, 49.3 mg/L in suspended substances, and 203.7 mg/L in sediments. The average value of Cd in soil from the polluted area is 83.0 mg/kg. Natural weathering of Cd-rich rocks and minerals imposes a potential environmental risk on the aquatic ecosystem of the Bijiang catchment. [ABSTRACT FROM AUTHOR]

Zircon U-Pb dating by the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite complex, among which the East Guposhan unit is 160.8±1.6 Ma, the West Guposhan unit is 165.0±1.9 Ma, and the Lisong unit is 163.0±1.3 Ma in age. Much similarity in ages of the three units has thus proved that the whole Guposhan granite complex was formed in the same period of time. They were the products of large-scale granitic magmatism through crust-remelting in the first stage of the Middle Yanshanian in South China. However, the three units have differences both in petrology and in geochemistry. Besides the differences in major, trace and rare-earth elements, they are distinct in their Rb-Sr and Sm-Nd isotopic compositions. The East Guposhan unit and Lisong unit and its enclaves have a similar (87Sr/86Sr)i value of 0.7064 with an average of ɛNd( t)=−3.03, indicating that more mantle material was evolved in the magma derivation; whereas the West Guposhan unit has a higher (87Sr/86Sr)i value of 0.7173 but a lower ɛNd( t) value of −5.00, and is characterized by strong negative Eu anomalies and higher Rb/Sr ratios, suggesting that its source materials were composed of relatively old crust components and new mantle-derived components. In addition, an inherited zircon grain in the East Guposhan unit (GP-1) yielded a 206Pb/238U age of 806.4 Ma, which is similar to the ages of the Jiulin cordierite granite in northern Jiangxi and of the Yinqiao migmatic granite in Guangxi in the HZH granite zone. All this may provide new evidence for Late Proterozoic magmatism in the HZH granite zone. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

A systematic analysis of the inorganic and organic geochemistry of Middle Permian source rocks comprising carbonate rocks and mudstones was carried out, with samples collected from the outcrop and bore of the Junggar, Turpan and Ili basins in northern Xinjiang. This study confirmed that sedimentary parameters for an ancient water body, such as inorganic geochemistry and paleosalinity, have a close relation to the organic matter of source rocks. It is also disclosed that phytane predominance in the source rocks is mainly due to a reducing environment. Biomarkers, such as gammacerane and β-carotene, in the samples reflect a specific salinity in the sedimentary environments. Sedimentary zones with a strong reducing environment are more likely to produce deposits of primary organic matter, which will be buried and preserved contemporarily. Consequently, the source rocks are generally high in organic content and better in organic type than ordinary ones, and vice versa. [ABSTRACT FROM AUTHOR]

Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle (EM II) source. The data available indicated they are alkali-rich (K2O + Na2O > 8wt%) and shoshonitic. Although formed in a within-plate environment they exhibit signatures of arc magmatic rocks, such as high amounts of LILE and LREE relative to the HFSE and HREE, and thus high Ba/Nb, Ba/Zr, Sr/Y, La/Yb ratios as well as mimic chondrite-normalized REE and primitive mantle-normalized trace element patterns of subducted sediments, and they fall in the collision- or arc-related tectonic setting field on all discrimination diagrams. This might suggest the enrichment be related to the substantial extent of sediment contamination by the Mesozoic Tethyan subduction processes. [ABSTRACT FROM AUTHOR]

Based on the REE geochemistry data from the Baimazhai nickel deposit, Yunnan Province, the authors modeled the composition of the mantle source region by way of petrological mixing calculation, and further discussed the genesis of this type of rocks. Both element geochemistry data and mixing calculation showed that lamprophyres in the Baimazhai nickel deposit were derived from a metasomatism-enrichment mantle and the fluids resulted from dehydration of a subducted slab which is comprised of ALK-, LREE- and incompatible element-rich sediments. [ABSTRACT FROM AUTHOR]

The Duolanasayi gold deposit, 60 km NW of Habahe County, Xinjiang Uygur Autonomous Region, is a mid-large-scale gold deposit controlled by brittle-ductile shearing, and superimposed by albitite veins and late-stage magma hydrothermal solutions. There are four types of pyrite, which are contained in the light metamorphosed rocks (limestone, siltstone) , altered-mineralized rocks (chlorite-schist, altered albite-granite, mineralized phyllite) , quartz veins and carbonatite veinlets. The pyrite is the most common ore mineral. The Au-barren pyrite is present mainly in a simple form and gold-bearing pyrite is present mainly in a composite form. From the top downwards, the pyrite varies in crystal form from |100| and |210| + l100l to |210l + |100| + |111| to |100| + |111|. Geochemical studies indicate that the molecular contents of pyrite range from Fe1.057 S2 to Fe0.941S2. Gold positively correlates with Mn, Sr, Zn, Te, Ph, Ba and Ag. There are four groups of trace elements: Fe-Cu-Sr-Ag, Au-Te-Co, As-Ph-Zn and Mn-V-Ti-Ba-Ni-Cr in pyrite. The REE characteristics show that the total amount of REE ranges from 32.35 x 10-6 to 132.18 x 10-6; LREE/HREE, 4.466 - 9.142; (La/Yb)N, 3.719 - 11.133; (Eu/Sm)N,, 0.553 - 1.656; (Sm/Nd)N, 0.602 - 0.717; La/Yb, 6.26 - 18.75; δEu, 0.628 - 2.309; δCe, 0.308 - 0.816. Sulfur isotopic compositions (δ 38S = -2.46% - -7.02%) suggest that the sulfur associated with gold mineralization was derived from the upper mantle or lower crust. [ABSTRACT FROM AUTHOR]