Showing papers in "Chinese Journal of Geochemistry in 2005"
TL;DR: The estimated annual loss amount of COD, BOD, NH3-N from manure in 2001 is 7.28 million ton, 4.99 million ton and 1.32 million ton as mentioned in this paper.
Abstract: With economic development and living standard improvement, livestock and poultry production has grown up rapidly, also has become the leading source of pollution in vast rural areas in China. The estimated annual loss amount of COD, BOD, NH3-N from manure in 2001 is 7. 28 million ton, 4.99 million ton and 1.32 million ton, respectively. The COD loss amount from manure is close to the sum of COD from industrial and domestic wastewater. Because animal waste and wastewater can enter water bodies from spills or breaks of waste storage structures (due to accidents or excessive rain), and non-agricultural application of manure to cropland, this contamination has resulted in quality degradation of surface and underground drinking water supplies. Areas with concentrated livestock operations are showing elevated nutrients and organic pollutant contents in surface waters. This widespread contamination of water has prompted governments at various levels to adopt regulations and measures to control the spreading of livestock pollution.
16 citations
TL;DR: In this article, eutrophication monitoring in the 135m backwater reach of the Daning River was conducted and the data were simply analyzed, and the assessment result is that water body in the segment from Shuanglong to Longmen was mesotrophic or eutrophic.
Abstract: The Daning River is a very important tributary in the Three Gorges Reservoir area. It is also a famous scenic spot. Anomalies appeared after water storage of the reservoir in June, 2003. In September, 2003, eutrophication monitoring in the 135-m backwater reach of the Daning River was conducted and the data were simply analyzed. The assessment result is that water body in the segment from Shuanglong to Longmen was mesotrophic or eutrophic. At the same time, the causes of its nutritional change were discussed, and counter-measures have been proposed.
14 citations
TL;DR: In terms of environmental mineralogy, the environmental properties of metallic minerals, including chemical activation, adsorption, pore effect and nanometer effect, have been analyzed in this article.
Abstract: In terms of environmental mineralogy, the environmental properties of metallic minerals, including chemical activation, adsorption, pore effect and nanometer effect, have been analyzed. On the basis of the analysis of environmental properties of metallic minerals, the applications of iron-bearing sulfides, iron and manganese oxides in the purification of wastewaters containing heavy metal ions (Cr6+, Hg2+, Pb2+, etc.) have been summarized. Moreover, research on the application of metallic minerals in environmental protection has been anticipated. It should be a piece of dominating work for environmental mineralogic researchers in the future to lucubrate systematically the physical and chemical characteristics of the metallic mineral surfaces, further reveal the reciprocity process between metallic minerals and water surface, perfect the theory and model of the metallic minerals to remove contaminants, intensify study on the facilities and techniques of metallic minerals to remove contaminants, and entail well the extension and propagation of achievements.
13 citations
TL;DR: In this paper, trap preconcentration and CVAFS and CVAAS detection methods were used to detect mercury species in water column, sediment and fish from the Hg-contaminated Baihua Reservoir.
Abstract: Mercury species in water column, sediment and fish from the Hg-contaminated Baihua Reservoir were measured by trap pre-concentration and CVAFS and CVAAS detection methods. The results showed that the highest average total Hg concentration is up to 73.36 ng/L in the water column, 186.7 ng/L in pore water of surface sediment in the Baihua Reservoir. The total mercury concentrations in the sediments range from 0.87 to 33.74 mg/kg. This suggests that sediment re-suspending and Hg input from the upstream organochemical plant are the main mercury sources of water body for this reservoir. In addition, the possible reason why mercury is low in fish is that the low DOC and high pH are infavarable to methylmercury formation or absorption by fish.
11 citations
TL;DR: In this paper, the authors studied the distribution of nutrients (N, P, Si, C) in the Wujiang River surface water during the high-flow and low-flow periods in 2002.
Abstract: The distribution of nutrients (N, P, Si, C) in the Wujiang River surface water was studied during the high-flow and low-flow periods in 2002. The results showed that nitrate nitrogen (NO3-N) is the main form of dissolved inorganic nitrogen (DIN) in the Wujiang River Basin. It accounts for about 90% of DIN. The average NO3-N concentrations in the mainstream are 147.5 µM in the high-flow period and 158.0 µM in the low-flow period, respectively. The average concentrations of total phosphorus (TP) are 6.43 µM in the high-flow period and 4.18 µM in the low-flow period, respectively. Of the various forms of phosphorus, particulate phosphorus (PP) has the highest percentage (62.9%) of TP in the high-flow period. In the low-flow period, however, phosphate is the main form of phosphorus, which accounts for 49% of TP. With the Wujiangdu Reservoir as the boundary, the concentrations of DIN and phosphorus in the upper reaches are different from those in the lower reaches of the Wujiang River. As a whole, the concentrations of DIN and phosphorus are both higher in the low-flow period than in the high-flow period. The spatial and temporal variations of DIN and phosphorus concentrations suggested that DIN and phosphorus come from agricultural and domestic wastewaters and groundwaters and that the Wujiangdu Reservoir has an important impact on the concentrations and distribution of DIN and phosphorus in the Wujiang River. The distribution patterns of dissolved silica (DSi) and dissolved organic carbon (DOC) are similar. Both of them maintain no change in the whole course of the river and their concentrations (with the exception of the reservoir itself) are higher in the high-flow period than in the low-flow period. The average DSi and DOC concentrations in the mainstream are 85.4, 84.6 µM in the high-flow period and 60.8, 53.9 µM in the low-flow period, respectively. The concentrations of nutrients in most of the major tributaries are lower than in the mainstream. This suggested that the contributions of most tributaries are relatively small but importance should be attached to the influence of some individual tributaries such as the Qingshuijiang River and the Weng’ an River on the mainstream.
10 citations
TL;DR: In this paper, the authors investigated the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations.
Abstract: The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations. The RICO products included n-alkanoic acids, α, ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid, regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bounded on the asphaltenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C28 sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tahe oilfields.
9 citations
TL;DR: In this paper, the distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed and differences between the East and the West basins were compared.
Abstract: The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Luliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.
9 citations
TL;DR: In this article, sequential core sediments from northwestern Taihu lake in China were analyzed for grain size, organic carbon and heavy metal content, showing heavy metal pollution history of the sediments has been recorded since the late 1970s, determined by the result of137Cs dating.
Abstract: Sequential core sediments from northwestern Taihu Lake in China were analyzed for grain size, organic carbon and heavy metal content. The sediments are composed of organic-poor clayey-fine silts. The chemical speciations of Cu, Fe, Mn, Ni, Pb, and Zn were also analyzed using the BCR sequential extraction procedure. Cu, Fe, Ni, and Zn are mainly associated with the residue fraction; Mn is concentrated mainly in exchangeable/carbonate fraction and residue fraction; and Pb mainly in Fe/Mn oxide fraction and organic/sulfide fraction. The exchangeable/carbonate fractions of Cu, Fe, Ni, Zn and Pb are lower. The fractions of Ni, Pb and Zn bound to the Fe/Mn oxide have significant correlations with reducible Mn; the organic/sulfide fractions of Cu, Mn, Ni, Pb, and Zn have significant correlations with TOC. The extractable fractions of Cu, Mn, Ni, Pb, and Zn are high at the top 4 cm of the core sediments as compared to those in the deeper layers, showing the anthropogenic input of heavy metals is due to rapid industrial development. The heavy metal pollution history of the sediments has been recorded since the late 1970s, determined by the result of137Cs dating.
9 citations
TL;DR: In this article, rare-earth element (REE) data from the Gezhongwu phosphorites of Zhijin was used to investigate the depositional conditions of the Meishucun Formation.
Abstract: The Cambrian Gezhongwu Formation in Southwest China is the lowest Cambrian phosphorite unit. The Formation belongs to the Meishucun stage with small shelly fossils. Rare-earth element (REE) data from the Gezhongwu phosphorites of Zhijin documented the depositional conditions. The total REE concentrations are high in the Gezhongwu phosphorites, which are especially rich in yttrium. The PAAS-normalized REE patterns of the Gezhongwu phosphorites are characterized by negative Ce anomalies and slight enrichment of MREE, as being hat-shaped. The hat-shaped patterns suggest that the REE originated from depositional environments rather than from subsequent diagenesis. The negative Ce anomalies indicate that the depositional environments are oxic. The positive Eu anomaly, the high total REE and the hat-shaped REE pattern revealed contributions from the normal marine environment mixed with hydrothermal water to the REE budget of the Gezhongwu phosphorites.
8 citations
TL;DR: In this article, seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow, and the total mercury in this river was mostly associated with suspended particles.
Abstract: Seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow. The total mercury in this river was mostly associated with suspended particles, particulate mercury accounting for 84% of the total mercury flux on average during the high flow period, and 52% of the total mercury flux on average in the low flow period. Significant losses of Hg from the water were observed in the downstreams of the reservoir. In addition, the concentrations of particulate mercury in the downstreams of reservoir appeared to have been enhanced by sediment re-suspension and shoreline erosion caused by flood discharge, while the filtered portion decreased. These observations suggested that reservoirs played an important role in controlling the transport and fate of mercury in the Wujiang River.
8 citations
TL;DR: In this article, the molecular and stable carbon isotopic compositions of methane, ethane and propane were used to identify the mixed gases of biogenic and mature thermogenic origins.
Abstract: Natural gases of shallow reservoirs with the carbon isotopic compositions of methane ranging from −50‰ to −60‰ (PDB) were considered as mixed gases of biogenic and thermogenic origins previously and some of them were considered as low-mature (or low temperature thermogenic) gases lately. In this paper natural gases with the carbon isotopic compositions of methane in the above range were identified using the molecular and stable carbon isotopic compositions of methane, ethane and propane. The mixed gases of biogenic and mature thermogenic origins display the characteristics of δ13C1 ranging from −50‰ to −60‰, δ13C2>−35‰, Δ values (δ13C3 - δ13C2)<5‰ and C1/ΣC
2
+
ratios 7‰, and C1/ΣC
2
+
ratios >60.
TL;DR: Taking low-concentration anthracene as internal standard, the absolute concentrations of fingerprints are calculated, some experiments directly on biodegradation of crude oils are made, and production allocation in the Gudong Oil field is calculated.
Abstract: Gas chromatography fingerprint technique has the advantages of fast performance and low cost. It can be used to conduct analysis without interruption either in the field or at laboratory. This technique has been used successfully in such cases that conventional production logging techniques are powerless. Taking low-concentration anthracene as internal standard, we calculated the absolute concentrations of fingerprints, initially made some experiments directly on biodegradation of crude oils, and calculated production allocation in the Gudong Oil field. Compared with the production logging, this method has made up for the deficiencies of the former GC fingerprint technique. It will find wide applications in monitoring the trend of production in various oil-fields.
TL;DR: In this article, a quantitative estimation of Ca, Mg, Fe and Ni in soil and plant ash has been carried out and the constituents of plant ash have been discussed in relation to soil chemistry, pH, climate, mobility, average abundance in plant ash and exclusion mechanism of the flora.
Abstract: Nannorrhops ritchiana (Mazari Palm) is a distinctive flora growing in the Saharo-Sindian region. It is well distributed on the ultramafic soil, derived from the Bela Ophiolite in the Khuzdar District, Balochistan, Pakistan. Quantitative estimation of Ca, Mg, Fe and Ni in soil and plant ash has been carried out. The constituents of plant ash have been discussed in relation to soil chemistry, pH, climate, mobility, average abundance in plant ash and exclusion mechanism of the flora. Relationship among Ca, Mg, Fe and Ni has been established using scattergrams to evaluate the biogeochemistry of the plant. High contents of Mg and high coefficient of biological absorption allow it to be classed as Mg-flora. Both Ca and Fe appeared to be antagonistic to Mg. The metal assemblage ofN. ritchiana nicely reflected the nature of the bed rock as being serpentinized ultramafic, and its corresponding soils. Good exclusion mechanism ofN. ritchiana did not allow it to absorb high Ni from the soil. Relatively high concentrations of Ni inN. ritchiana from the Baran Lak area can be used to localize Ni-mineralization in the study area.
TL;DR: The Huize large-sized Pb-Zn deposit in Yunnan Province, China, is characterized by favorable metallogenic background and particular geological settings as mentioned in this paper, which suggested that the ore-forming mechanism is relatively unique.
Abstract: 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 O 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.
TL;DR: The sedimentary-volcanic tuff (locally called green-bean rock) formed during the early Middle Triassic volcanic event in Guizhou Province is characterized as being thin, stable, widespread, short in forming time and predominantly green in color as mentioned in this paper.
Abstract: The sedimentary-volcanic tuff (locally called “green-bean rock”) formed during the early Middle Triassic volcanic event in Guizhou Province is characterized as being thin, stable, widespread, short in forming time and predominantly green in color. The green-bean rock is a perfect indicator for stratigraphic division. Its petrographic and geochemical features are unique, and it is composed mainly of glassy fragments and subordinately of crystal fragments and volcanic ash balls. Analysis of the major and trace elements and rare-earth elements (REE), as well as the related diagrams, permits us to believe that the green-bean rock is acidic volcanic material of the calc-alkaline series formed in the Indosinian orogenic belt on the Sino-Vietnam border, which was atmospherically transported to the tectonically stable areas and then deposited as sedimentary-volcanic rocks there. According to the age of green-bean rock, it is deduced that the boundary age of the Middle-Lower Triassic overlain by the sedimentary-volcanic tuff is about 247 Ma.
TL;DR: 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 as mentioned in this paper.
Abstract: 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.
TL;DR: The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-are-naceous rocks, with minor amphibolite.
Abstract: The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-are-naceous rocks, with minor amphibolite. These rocks underwent amphibolite-facies metamorphism. The meta-argillo-arenaceous rocks show large variations in major element composition, but have similar REE patterns and trace element composition, incompatible element and LIE enrichments [high Th/Sc (0.57−3.59), La/Sc (1.46−12.4), La/Yb (5.84−19.0)] and variable Th/U ratios, with ΣREE=129−296µg/g, δEu=0.51−0.86, and (La/Yb)N=3.95−12.9. The Nd isotopic model agest DM of these rocks vary from 1597 to 2124 Ma. Their143Nd/144Nd values are low [ɛNd(0)=−11.4 to −15.8]. Some conclusions have been drawn as follows: (1) The metamorphic rocks in central Jiangxi Province are likely formed in a tectonic environment at the passive continental margin of the Cathaysia massif. (2) The metamorphosed argillo-arenaceous rocks are composed dominantly of upper crustal-source rocks (Al- and K-rich granitic or/and sedimentary rocks of Early Proterozoic), which experienced good sorting, slow deposition and more intense chemical weathering. (3) According to the whole-rock Sm-Nd isochron ages (1113±49 to 1199±26 Ma) of plagioclase-amphibole (schist) and Nd isotopic model aget DM (1597−2124 Ma) of meta-argillo-arenaceous rocks, the metamorphic belt in central Jiangxi Province was formed during the Middle Proterozoic (1100−1600 Ma).
TL;DR: In this article, the authors shed light on the hydrogeochemical characteristics of karst underground waters at shallow depth in Guiyang City, Guizhou Province with an emphasis on the geochemistry of major elements.
Abstract: The aim of this study is to shed light on the hydrogeochemical characteristics of karst underground waters at shallow depth in Guiyang City, Guizhou Province with an emphasis on the geochemistry of major elements. Guiyang City bears abundant underground waters and it is also an important representative of the karst areas throughout the world. Ca2+ and Mg2+ are the dominant cations, accounting for 81% – 99.7% of the total, and HCO3- and SO42- are the dominant anions. Weathering of limestones and dolostones is the most important factor controlling the hydrogeochemistry of underground waters, and weathering of sulfate and evaporite rocks is less important. Moreover, the precipitation and human activities also have a definite influence on the hydrogeochemistry of underground waters in the region studied.
TL;DR: Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle (EM II) source as discussed by the authors, and the data available indicated they are alkali rich (K2O + Na2O > 8wt%) and shoshonitic.
Abstract: 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.
TL;DR: In this article, a range of rare-earth element (REE) abundances and distinctive patterns from highly fractionated patterns with negative Eu anomalies in granitic rocks to relatively low abundance and less REE fractionated flat patterns with little Eu anomaly in some paragneisses, schists, enderbites and dolentes.
Abstract: Rock samples representing various igneous and metamorphic rocks of southern Obudu Plateau were analyzed for rare-earth element (REE) behavior by ICP-MS. Results of the analyses indicate a range of REE abundances and distinctive patterns from highly fractionated patterns with negative Eu anomalies in granitic rocks to relatively low abundances and less REE fractionated flat patterns with little Eu anomaly in some paragneisses, schists, enderbites and dolentes to unfractionated patterns with positive Eu anomalies in some paragneisses and charnockites. Over all, there are low to high e REE contents with negative to positive Eu anomalies. The ratios of different parameters, especially La/Yb and Ce/Yb, show behaviors consistent with crustal to mantle derivation. The heterogeneity of REE abundances and REE patterns reflects mantle to crustal petrogenetic variations of different rock suites on the Plateau. The LREE content is higher than the HREE content in the highly differentiated rocks, as evidenced by their La/Yb, Ce/Yb and La/Sm ratios, which are normally higher in residual products than in primary melts. The dominantly intermediate nature of the source rock of the orthogneisses is suggested by the generally low e REE. The granites enriched in LREE and depleted in HREE and some of the charnockites with negative Eu anomalies were probably formed by partial melting and crystallization.
TL;DR: In this paper, micro-thermometric measurements of fluid inclusions in the PGE-polymetallic deposits hosted in the Lower Cambrian black rock series in southern China were performed.
Abstract: Systematic microthermometric measurements of fluid inclusions in the PGE-polymetallic deposits hosted in the Lower Cambrian black rock series in southern China were performed, and the results suggest: (1) there exist two types of fluid inclusions. Type I is of NaCl-H2O system with low-medium salinity, and its homogenization temperatures (T
h) and salinities are 106.9 – 286.4°C and (0.8 – 21.8) wt% NaCl eq. respectively; Type II is of CaCl2-NaCl-H2O system with medium-high salinities, and its homogenization temperatures and salinities range from 120.1°C to 269.6°C and (11.4 – 31.4) wt% NaCl eq., respectively. The type II fluid inclusions have been discovered for the first time in this kind of deposits; (2) two generations of ore-forming fluids were recognized. Characteristics of fluid inclusions in the PGE-polymetallic ores and carbonate-quartz stockworks in the underlying phosphorites are almost of no difference, they may represent ore-forming fluids at the main metallogenic stage. The peak value of homogenization temperature of those fluid inclusions is about 170°C, while their salinities possess a remarkable bimodal distribution pattern with two peak values of (27 – 31) wt% NaCl eq. and (4 – 6) wt% NaCl eq. On the contrary, fluid inclusions in the carbonate-quartz veins in the hanging wall may represent ore-forming fluids at the post-metallogenetic stage. The homogenization temperatures and the peak values of salinities are mostly 130 – 170°C and (12 – 14) wt% NaCl eq., respectively; (3) nobel gas isotopic composition analyses in combination with the microthermometric measurements of fluid inclusions suggest that the ore-forming fluids at the main metallogenetic stage were probably derived from mixing of basinal hot brines with the CaCl2-NaCl-H2O system and seawater with the NaCl-H2O system; (4) in the Early Cambrian, the basinal hot brines were trapped in the Caledonian basins, which were distributed along the southern margin of the Yangtze Craton, and where giant thick sediments were accumulated, and expelled and migrated laterally along the strata because of the pressure caused by overlying sediments. The basinal hot brines absorbed Ni, Mo, V, PGE from the surrounding rocks and were transformed into ore-bearing hydrothermal fluids with the CaCl2-NaCl-H2O system and medium-high salinities, then ascended along faults and mixed with seawater of the NaCl-H2O system, and finally PGE-polymetallic deposits or occurrences were formed in the black rock series.
TL;DR: The geochemistry data show that the total organic carbon (TOC) contents are high in the surface sediments in the eastern part of the Moknine's Sebkha as discussed by the authors.
Abstract: The geochemistry data show that the total organic carbon (TOC) contents are high in the surface sediments in the eastern part of the Moknine’s Sebkha. Low decreasing of organic matter (OM) with increasing depth indicates the good preservation of OM in modern sediments. “Lignite levels” inserted in the sand sequence and deposited at the edge and in the intermediate zone are considered as lithologic and organic markers. It is characterized by high TOC and poor hydrogen index (HI), indicating a higher plant origin and good preservation of OM in thin beds under anoxic condition.
TL;DR: In this paper, the authors found that hydrogen donation for thermochemical sulfate reduction (TSR) occurred in alkylated phenanthrenes and naphthalenes, leading to the decrease of 12 biomarker parameters during the Kupferschiefer mineralization.
Abstract: Molecular biomarkers are the important maturity parameters for sedimentary organic matter. They have also been widely used for determining the maturity of organic matter in ore deposits. However, during the study of organic matter in the Kupferschiefer from the Lubin mine, it had been found that the biomarkers were influenced by sulfide formation. In order to probe into the degree of influence on biomarkers, seven samples collected from a Kupferschiefer section from the Lubin mine were analyzed by various geochemical methods. The results indicated that in the samples with higher copper contents, the values of biomarkers are lower than in the samples with lower copper contents. In highly mineralized samples, hydrogen donation for thermochemical sulfate reduction (TSR) occurred in alkylated phenanthrenes and naphthalenes, leading to the decrease of 12 biomarker parameters during the Kupferschiefer mineralization.
TL;DR: In this article, the carbon isotopic values tend to increase with burial depth, the oils become from immature-low mature to mature, and the rules of evolution of oils show a three-stage evolution pattern, i.e., light→heavy→light→heavy oils.
Abstract: The Jiyang Sag and the Liaohe Basin are the two important areas where immature oil resources are distributed in China. From these two areas immature-low mature to mature oil samples were collected for carbon isotopic analysis. The extracts of source rocks are dominant in the Jiyang Sag while crude oils are dominant in the Liaohe Basin. The maturity index, Ro, for source rocks varies from 0.25% (immature) to 0.65% (mature). Studies have shown that within this range of Ro values the extracts of source rocks and crude oils, as well as their fraction components, have experienced observable carbon isotope fractionation. The carbon isotopic values tend to increase with burial depth, the oils become from immature-low mature to mature, and the rules of evolution of oils show a three-stage evolution pattern, i. e., light→heavy→light→heavy oils. Such variation trend seems to be related to the occurrence of two hydrocarbon-generating processes and the main hydrocarbon-forming materials being correspondingly non-hydrocarbons and possessing MAB characteristics, lower thermodynamic effects and other factors. In the process towards the mature stage, with increasing thermodynamic effects, the thermal degradation of kerogens into oil has become the leading factor, and correspondingly the bond-breaking ratio of12C-13C also increases, making the relatively12C-rich materials at the low mature stage evolve again towards13C enrichment.
TL;DR: In this paper, the authors concluded that the early-stage ore-forming fluid from the Jinchangqing gold (copper) ore deposit is a kind of sulfate type hot brine characterized by medium temperature and salinity, genetically related to the late-stage mine fluid derived from an acidic and more reductive environment.
Abstract: On the basis of results of the studies of primary fluid inclusions, and the hydrogen and oxygen isotope data, the authors concluded that the early-stage ore-forming fluid from the Jinchangqing gold (copper) ore deposit is a kind of sulfate type hot brine characterized by medium temperature and salinity, genetically related to the late-stage ore-forming fluid derived from an acidic and more reductive environment. However, the late-stage ore-forming fluid is a sort of low temperature and low salinity chloride-type hot brine which originated from a lower pressure, acidic and more oxidative environment. In general, the ore fluids were derived from the late-stage, or largely from the early-stage groundwater-derived meteoric water, which has a 12% – 17% heavier oxygen isotopic composition than the original rain water (δ18O = — 15. 3%), and were formed during gold mineralization as a product of oxygen isotope exchange during the reaction between ore-forming fluid and wall rocks under a lower water/rock ratio condition.
TL;DR: In this paper, the K1 values of C7 isoalkanes, cyclopentane, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically.
Abstract: Light hydrocarbons, especially C7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K1 values [(2-MH+2,3-DMP)/(3-MH+2,4-DMP)] of crude oils vary from a lowest value of 0.78, to a highest value of 1.54, but the K1 values of the majority of oil samples (80%) range from 0.90 to 1.20. However, the absolute contents of (2-methylhexane+2,3-dimethylpentane) and (3-methylhexane+2,4-dimethylpentane) in the total light hydrocarbons (C4–C7) show a similar variation trend. The variation of K1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C7 light hydrocarbons in light of the steady-state catalytic hypothesis, nonmarine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.
TL;DR: In this paper, the authors classified heavy oil of the Erlian Basin into two genetic types: the primary and the secondary heavy oil, which can be divided into two types: primary heavy oil is generated directly by Cretaceous immature or low-mature hydrocarbon sources, or is derived from differentiation of crude oil during migration.
Abstract: Heavy oil is commonly distributed in the Erlian Basin, North China. It can be divided into two genetic types: the primary and the secondary. Primary heavy oil is generated directly by Cretaceous immature or low-mature hydrocarbon sources, or is derived from differentiation of crude oil during migration. Oil of this type has viscosity varying in the range of 100–5000 mPa · s. By contrast, secondary heavy oil, which has been thickened to various degrees, is resultant from a combination of biodegradation, water-leaching and oxidation of primary heavy oil. Based upon a large number of determinations on the physical properties of crude oil, GC analyses of saturated and aromatic hydrocarbons, and GC-MS analyses of steranes and terpanes, the characteristics of heavy oil of various types have been described. Differences in inspissation degree have made it possible the grouping of heavy oil of the Erlian Basin into an inspissation series, i. e., low maturity and immature heavy oil with viscosity of 100–2000 mPa · s, weakly biodegradated heavy oil with viscosity of 500–5000 mPa · s, moderately biodegradated heavy oil with viscosity of 1000–50000 mPa · s and highly biodegradated heavy oil with viscosity over 50000 mPa · s. With the progress of inspissation, the products vary from common heavy to over-heavy oil. Slope and uplifted areas inside a reservoir basin are most favorable to the inspissation and formation of heavy oil. Interaction of several mechanisms of inspissation has resulted in a widespread distribution of heavy oil within the Erlian Basin.
TL;DR: The early Early Cambrian strata within the bounds of Guizhou Province are almost predominated by black shale deposition as mentioned in this paper, which provides favorable conditions for the study of marine geochemical characteristics of the early early Cambrian.
Abstract: The early Early Cambrian strata within the bounds of Guizhou Province are almost predominated by black shale deposition. Recently, however, the authors have found a section consisting of a set of mudstones interbedded with limestones at the basement of the Cambrian at Yingping, Fuquan County, Guizhou Province, which provides favorable conditions for the study of marine geochemical characteristics of the early Early Cambrian. The characteristics of intense negative carbon isotopic anomalies near the Precambrian/Cambrian boundary at Yingping, Fuquan County, Guizhou Province, can be correlated with those of global carbon isotopic anomalies at the same time on a global scale, corresponding to the intense negative carbon isotopic anomalies near the Neoproterozoic/Cambrian boundaries at the bottom of the Xiaowaitoushan Member, Huize, Yunnan Province, at the top of the Tsagaan Oloom Formation of Mongolia and at the top of the Salarmy Gol Formation of Siberia, as well as those observed in southwestern United States, Iran, Amman, Poland, Newfoundland, the Great Britain, Canada, etc. Negative carbon isotopic anomalies can be used as the important basis for the division of the Precambrian/Cambrian boundaries. There have been found 8 m-thick black shales and cherts below the intense negative carbon isotopic anomalies in this profile. In the black shales there have been found large amounts of fossils such asBradorida, gernusArchotuba, indicating that during the period of sedimentation of black shales under anaerobic conditions there would be large quantities of organic species living in the sea. But in the section of grayish-green mudstones interbedded with limestones with intense negative carbon isotopic anomalies almost no organic fossil has been found. This may imply that the anaerobic event seems to have little bearing on the mass extinction near the Precambrian/Cambrian boundary, whereas the intense negative carbon isotopic anomaly event appears to be more closely related to the mass extinction occurring near the Precambrian/Cambrian boundary.
TL;DR: In this article, the authors reviewed the main laboratory experiments, which depend on simulate samples, lunar soil samples, telescope observations and spacecraft data, performed by all kinds of work on the lunar opposition effect.
Abstract: Photometry is one of the main methods of planetary remote sensing. The opposition effect is a sharp surge in brightness around zero phase angles. Research on opposition effect is an important branch of photometry and also is an important tool in remote sensing of the Moon. In this paper, we reviewed the main laboratory experiments, which depend on simulate samples, lunar soil samples, telescope observations and spacecraft data, performed by all kinds of work on the lunar opposition effect. And we also reviewed the theoretical development of the lunar opposition effect (i.e., the major causes of the lunar opposition effect): the shadow hiding mechanism causes the lunar opposition effect, which includes the famous models (Hapke model and Lumme & Bowell model); then, the coherent backscatter mechanism; and now, the model combining the shadow hiding and coherent backscatter. China has sponsored the Chang’ e plan of lunar exploration, and the plan along with the SMART-1 gives a good chance to lunar opposition effect research when the data on the opposition surge at very small phase angles are obtained by the spacecrafts.
TL;DR: In this paper, 19 trace metals in PM10 were measured by X-ray fluorescence spectroscopy (XRF) at three sites in Chongqing, and the source identification indicated that particulate materials were contributed mainly by two sources.
Abstract: Nineteen trace metals in PM10 were measured by X-ray fluorescence spectroscopy (XRF) at three sites in Chongqing. The special and seasonal variations of trace metals in PM10 samples collected in the downtown were different from those in the background area of Jinyunshan. The source identification indicated that particulate materials were contributed mainly by two sources.