bluuebunny/crossref_metadata_2025 huggingface dataset:
Sedimentary Features and Implications for the Precambrian Non‐stromatolitic Carbonate Succession: A Case Study of the Mesoproterozoic Gaoyuzhuang Formation at the Qiangou Section in Yanqing County of Beijing
Authors: Mingxiang MEI
Published: September 2010

Abstract: In the long Precambrian period, stromatolitic carbonate successions were very common. However, the non‐stromatolitic carbonate succession that is marked by subtidal deposits shows a sharp contrast to the stromatolitic carbonate succession. Both the non‐stromatolitic and the stromatolitic carbonate successions are important clues for the further understanding of the evolving carbonate world of the Precambrian. The Mesoproterozoic Gaoyuzhuang Formation at the Qiangou section in northwestern suburb of Beijing is a set of more than 1000 m‐thick carbonate strata that can be divided into four members (or subformations), in which a non‐stromatolitic carbonate succession marked by the scarcity of stromatolites makes up the third member of the formation. This non‐stromatolitic carbonate succession can further be subdivided into three third‐order sequences that are marked by the regular succession of sedimentary facies. In third‐order sequences, a lot of subtidal carbonate meter‐scale cycles made up of medium‐bedded leiolite limestones and thin‐bedded marls constitute their transgressive system tracts (TSTs) and the early high‐stand system tracts (EHSTs), a lot of meter‐scale cycles made up by thin‐bedded limestones and marls constitute their condensed sections (CSs), and thick‐bedded to massive dolomitic limestones or lime dolomites make up the late high‐stand system tracts (LHSTs). The particularly non‐stromatolitic carbonate succession making up the third member of the Mesoproterozoic Gaoyuzhuang Formation at the Qiangou section might be the representative of the non‐stromatolitic carbonate succession of the Precambrian because of its special lithological features and particular sedimentary structures, and its general sedimentary features are helpful and meaningful for the further understanding of the evolution rules of the sophisticate and evolving carbonate world of the Precambrian. The time scale of the Gaoyuzhuang Formation is deduced as that from 1600 Ma to 1400 Ma; thus, the non‐stromatolitic sedimentary succession making up the third member of the Gaoyuzhuang Formation may demonstrate a stromatolite decline event occurring at ca. 1450 Ma of the Proterozoic besides other three events that occurred respectively at ca. 2000 Ma, ca. 1000 Ma and ca. 675 Ma. The forming duration of this non‐stromatolitic sedimentary succession of the third member of the Gaoyuzhuang Formation can be generally correlated with a similar sedimentary succession in North America, i.e. a non‐stromatolitic sedimentary succession of the Helena Formation of the Belt Supergroup, which suggests that the stromatolite decline occurring at ca. 1450 Ma might be a global event. Therefore, the non‐stromatolitic sedimentary succession discussed in the paper provides an important example for further understanding of carbonate sedimentology in the Precambrian.
Basin‐ and Mountain‐Building Dynamic Model of “Ramping‐Detachment‐Compression” in the West Kunlun‐Southern Tarim Basin Margin
Authors: Junwen CUI , Pengwu LI , Xianpu GUO , Xiaozhong DING , Zhemin TANG
Published: September 2010

Abstract: Analysis of the deformation structures in the West Kunlun‐Tarim basin‐range junction belt indicates that sediments in the southwestern Tarim depression were mainly derived from the West Kunlun Mountains and that with time the region of sedimentation extended progressively toward the north. Three north‐underthrusting (subducting), steep‐dipping, high‐velocity zones (bodies) are recognized at depths, which correspond to the central West Kunlun junction belt (bounded by the Küda‐Kaxtax fault on the north and Bulungkol‐Kangxiwar fault on the south), Quanshuigou fault belt (whose eastward extension is the Jinshajiang fault belt) and Bangong Co‐Nujiang fault belt. The geodynamic process of the basin‐range junction belt generally proceeded as follows: centering around the magma source region (which largely corresponds with the Karatag terrane at the surface), the deep‐seated material flowed and extended from below upward and to all sides, resulting in strong deformation (mainly extension) in the overlying lithosphere and even the upper mantle, appearance of extensional stress perpendicular to the strike of the orogenic belt in the thermal uplift region or at the top of the mantle diapir and localized thickening of the sedimentary cover (thermal subsidence in the upper crust). Three stages of the basin‐ and mountain‐forming processes in the West Kunlun‐southern Tarim basin margin may be summarized: (1) the stage of Late Jurassic‐Early Cretaceous ramping‐rapid uplift and rapid subsidence, when north‐directed thrust propagation and south‐directed intracontinental subduction, was the dominant mechanism for basin‐ and mountain‐building processes; (2) the stage of Late Cretaceous‐Paleogene deep‐level detachment‐slow uplift and homogeneous subsidence, when the dominant mechanism for the basin‐ and mountain‐forming processes was detachment (subhorizontal north‐directed deep‐level ductile shear) and its resulting lateral propagation of deep material; and (3) the stage of Neogene‐present compression‐rapid uplift and strong subsidence, when the basin‐ and mountain‐forming processes were simultaneously controlled by north‐vergent thrust propagation and compression. The authors summarize the processes as the “ramping‐detachment‐compression basin‐ and mountain‐forming dynamic model”. The basin‐range tectonics was initiated in the Late Jurassic, the Miocene‐Pliocene were a major transition period for the basin‐ and mountain‐forming mechanism and the terminal early Pleistocene tectonic movement in the main laid a foundation for the basin‐and‐mountain tectonic framework in the West Kunlun‐southern Tarim basin margin.
Archean Mass‐independent Fractionation of Sulfur Isotope: New Evidence of Bedded Sulfide Deposits in the Yanlingguan‐Shihezhuang area of Xintai, Shandong Province
Authors: Yanhe LI , Kejun HOU , Defang WAN , Guoliang YUE
Published: September 2010

Abstract: Multiple sulfur isotope ratios (34S/33S/32S) of Archean bedded sulfides deposits were measured in the Yanlingguan Formation of the Taishan Group in Xintai, Shandong Province, East of China; δ33S = −0.7%Δ to 3.8%, δ34S = 0.1%δ‐8.8%, Δ33S = −2.3% to −0.7%. The sulfur isotope compositions show obvious mass‐independent fractionation (MIF) signatures. The presence of MIF of sulfur isotope in Archean sulfides indicates that the sulfur was from products of photochemical reactions of volcanic SO2 induced by solar UV radiation, implying that the ozone shield was not formed in atmosphere at that time, and the oxygen level was less than 10−5 PAL (the present atmosphere level). The sulfate produced by photolysis of SO2 with negative Δ33S precipitated near the volcanic activity center; and the product of element S with positive Δ33S precipitated far away from the volcanic activity center. The lower Δ33S values of sulfide (‐2.30%Δ to −0.25%Δ) show that Shihezhuang was near the volcanic center, and sulfur was mostly from sulfate produced by photolysis. The higher Δ33S values (‐0.5%Δ to −2%Δ) indicate that Yanlingguan was far away from the volcanic center and that some of sulfur were from sulfate, another from element S produced by photolysis. The data points of sulfur isotope from Yanlingguan are in a line parallel to MFL (mass dependent fractionation line) on the plot of δ34S‐δ33S, showing that the volcanic sulfur species went through the atmospheric cycle into the ocean, and then mass dependent fractionation occurred during deposition of sulfide. The data points of sulfur isotope from Shihezhuang represent a mix of different sulfur source.
Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin, NW China, and Its Geological Significance
Authors: Chunyan LIU , Changsong LIN , Yi WANG , Maobing WU
Published: September 2010

Abstract: With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oilfield of the Tarim Basin, two stages of burial dissolution were put forward as an in‐source dissolution and out‐source dissolution based on macro‐microcosmic petrology and geochemistry features. The main differences in the two stages are in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in‐source fluid came from organic matter in the granule limestone itself, but the out‐source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in‐source and the out‐source dissolutions. The granule limestone firstly formed unattached pinholes under in‐source dissolution in situ, and afterwards suffered wider dissolution with out‐source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.
Application of Spectral Decomposition to Detection of Fracture‐Cavity Carbonate Reservoir Beds in the Tahe Oilfield, Tarim Basin, NW China
Authors: Xiaoping LIU , Xiaolan YANG , Yazhong ZHANG , Long HAN
Published: September 2010

Abstract: Ordovician fracture‐cavity carbonate reservoir beds are the major type of producing formations in the Tahe oilfield, Tarim Basin. The seismic responses of these beds clearly changes depending on the different distance of the fracture‐cavity reservoir bed from the top of the section. The seismic reflection becomes weak or is absent when the fracture‐cavity reservoir beds are less than 20 ms below the top Ordovician. The effect on top Ordovician reflection became weaker with deeper burial of fracture‐cavity reservoir beds but the developed deep fracture‐cavity reservoir beds caused stronger reflection in the interior of the Ordovician. This interior reflection can be divided into strong long‐axis, irregular and bead string reflections, and was present 80 ms below the top Ordovician. Aimed at understanding reflection characteristics, the spectral decomposition technique, which uses frequency to “tune‐in” bed thickness, was used to predict Ordovician fracture‐cavity carbonate formations in the Tahe oilfield. Through finely adjusting the processing parameters of spectral decomposition, it was found that the slice at 30 Hz of the tuned data cube can best represent reservoir bed development. Two large N‐S‐trending strong reflection belts in the mid‐western part of the study area along wells TK440‐TK427‐TK417B and in the eastern part along wells TK404‐TK409 were observed distinctly on the 30 Hz slice and 4‐D time‐frequency data cube carving. A small N‐S trending reflection belt in the southern part along wells T403‐TK446B was also clearly identified. The predicted reservoir bed development area coincides with the fracture‐cavities connection area confirmed by drilling pressure testing results. Deep karst cavities occur basically in three reservoir bed‐development belts identified by the Ordovician interior strong reflection. Spectral decomposition proved to be a useful technique in identifying fracture‐cavity reservoir beds.
Calculation of the CO2Degassing during Contact Metamorphism and Its Geological Significance: The Model and Example from the Shuanshan Area of the South Tan‐Lu Fault Belt
Authors: Xiaoyong YANG , Deliang LIU , Yongjian CHEN , Jinxing DAI
Published: September 2010

Abstract:The paper studies CO2degassing and controlling factors under the condition of contact metamorphism in the Shuangshan area, southern Tan‐Lu fault belt and the method of calculating the amount of CO2degassing. The results show that the amount of CO2degassing is controlled by the characteristics of the country rocks, including the thermal conductivity, penetrability, porosity and connectivity. Compositions, size and depth of intrusive rock also have an important influence on CO2degassing, i.e., they generated numerous cracks in the country rocks, and thus allowed the easy flow and accumulation of fluids. The amount of CO2flux in contact metamorphism is calculated quantitatively based on the metamorphic reaction and time‐integrated fluid flux. The value (0.729‐2.446×104mol/cm2) of CO2flux suggests that CO2was provided mainly by the contact metamorphic reaction. The generation and releasing of CO2are positively correlated with the degree of metamorphism, and XCO2in fluids gradually increases from dolomite zone to calcite zone, but in the zone of grossular, fluid flux is the largest and XCO2sharply decreases due to involvement of magmatic water. This study presents evidence that a large amount of industrial‐scale CO2can be produced during contact metamorphism. On the basis of theoretical and practical studies, a cone model has been proposed to response CO2degassing for the contact metamorphism, and it can be used to explore CO2accumulations beyond the oil‐gas basins. This model can also be applied to the study of inorganic genesis of CO2accumulations.
Genesis of Marine Carbonate Natural Gas in the Northeastern Sichuan Basin, China
Authors: Qu ZHANG , TENGER  , Qingqiang MENG , Jianzhong QIN , Qigui JIANG , Lunju ZHENG
Published: September 2010

Abstract: Sichuan Basin is one of the structurally stable and gas‐rich basins, being regarded as one of China's important natural gas industry bases. Puguang and Jiannan gas fields, located in the eastern Sichuan Basin are two large fields with gas derived from Permian and Lower Triassic marine carbonate. The genesis of marine carbonate natural gas was examined using carbon isotope composition and hydrocarbon components of natural gas samples from the eastern and western Sichuan Basin, and compared with that of acidolysis gas derived from marine source rock in the eastern Sichuan Basin. It is concluded that the natural gas in the marine carbonate reservoir originated from pyrolysis of the earlier crude oil and light‐oil, and then mixed with kerogen pyrolysis gas of the Permian and Lower Silurian source rock.
A New Understanding of Channel Patterns and Facies Models of the Shallow Lake Delta Facies of Fuyu Oil Reservoir in Songliao Basin, China
Authors: Yanping LI , Shumin CHEN , Yongzhong SONG , Erhua ZHANG , Jiagang SHEN , Jianbin ZHENG
Published: September 2010

Abstract: In the Fuyu Reservoir of Songliao Basin, there occur a series of well‐developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns: proximal/ distal meandering type distributary channels, proximal/distal low‐sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan‐4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan‐4th member.
A Study of the Migration and Accumulation Efficiency and the Genesis of Hydrocarbon Natural Gas in the Xujiaweizi Fault Depression
Authors: Jijun LI , Shuangfang LU , Haitao XUE , Qiuli HUO , Qingxia XU
Published: September 2010

Abstract: In order to investigate the migration and accumulation efficiency of hydrocarbon natural gas in the Xujiaweizi fault depression, and to provide new evidence for the classification of its genesis, a source rock pyrolysis experiment in a closed system was designed and carried out. Based on this, kinetic models for describing gas generation from organic matter and carbon isotope fractionation during this process were established, calibrated and then extrapolated to geologic conditions by combining the thermal history data of the Xushen‐1 Well. The results indicate that the coal measures in the Xujiaweizi fault depression are typical “high‐efficiency gas sources”, the natural gas generated from them has a high migration and accumulation efficiency, and consequently a large‐scale natural gas accumulation occurred in the area. The highly/over matured coal measures in the Xujiaweizi fault depression generate coaliferous gas with a high δ13C1 value (> −20%) at the late stage, making the carbon isotope composition of organic alkane gases abnormally heavy. In addition, the mixing and dissipation through the caprock of natural gas can result in the negative carbon isotope sequence (δ13C1 >δ13C2 >δ13C3 >δ13C4) of organic alkane gases, and the dissipation can also lead to the abnormally heavy carbon isotope composition of organic alkane gases. As for the discovery of inorganic nonhydrocarbon gas reservoirs, it can only serve as an accessorial evidence rather than a direct evidence that the hydrocarbon gas is inorganic. As a result, it needs stronger evidence to classify the hydrocarbon natural gas in the Xujiaweizi fault depression as inorganic gas.
Three Episodes of Hydrocarbon Generation and Accumulation of Marine Carbonate Strata in Eastern Sichuan Basin, China
Authors: Jianzhong QIN , Qingqiang MENG , Xiaodong FU
Published: September 2010

Abstract: It is concluded that there are three hydrocarbon generation and accumulation processes in northeastern Sichuan on the basis of the characteristics of solid bitumen, gas‐light oils‐heavy oils, homogenization temperature of fluid inclusions and diagenesis for beach‐ and reef‐facies dolomite gas‐bearing reservoirs in the Puguang Gas Field, northeastern Sichuan Basin, southern China. The first hydrocarbon generation and accumulation episode occurred in the Indosinian movement (late Middle Triassic). The sapropelic source rocks of the O3w (Upper Ordovician Wufeng Formation)‐S1l (Lower Silurian Longmaxi Formation) were buried at depths of 2500 m to 3000 m with the paleogeothermal temperature ranging from 70°C to 95°C, which yielded heavy oil with lower maturity. At the same time, intercrystalline pores, framework pores and corrosion caused by organic acid were formed within the organic reef facies of P2ch (Upper Permian Changxing Formation). And the first stage of hydrocarbon reservoir occurred, the level of surface porosity of residual solid bitumen {solid bitumen/ (solid bitumen + residual porosity)} was higher than 60%. The second episode occurred during the Middle Yanshanian movement (late Middle Jurassic). During that period, the mixed organic source rocks were deposited in an intra‐platform sag during the Permian and sapropelic source rocks of O3w‐S1l experienced a peak stage of crude oil or light oil and gas generation because they were buried at depths of 3500 m to 6800 m with paleogeothermal temperatures of 96–168°C. At that time, the level of surface porosity of residual solid bitumen of the T1f shoal facies reservoirs was between 25% and 35%, and the homogenization temperatures of the first and second stages of fluid inclusions varied from 100°C to 150°C. The third episode occurred during the Late Yanshanian (Late Cretaceous) to the Himalayan movement. The hydrocarbon reservoirs formed during the T1f and P2ch had the deepest burial of 7700 m to 8700 m and paleogeotemperatures of 177°C to 220°C. They could be cracked into dry gas (methane), and the same with the source rocks of the Permian and O3w‐S1l because they all reached the pyrolysis stage under such conditions. Consequently, the present natural gas (methane) reservoirs were developed.
Geological Characteristics of Oil and Gas Reservoirs in the Songpan‐Aba Area, SW China
Authors: Liguo CAI , Deliao YE , Guangxiang LIU
Published: September 2010

Abstract: The Songpan‐Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling‐Qilian oceanic crust subduction and ocean closure, the Caledonides were formed and the foreland basin was superimposed upon. Being influenced by the Paleo‐Tethyan extension, intra‐continental rifting‐margin basins were formed in Late Paleozoic. Following the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. The Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai‐Tibet Plateau domes. Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source‐reservoircap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages, and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoigê and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.
Analysis on Structural Control of Coal Distribution in the Northern Qaidam Basin, NW China
Authors: Tianji LIU , Tong WANG , Wenfeng ZHAN
Published: September 2010

Abstract: The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal‐controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal‐controlling structural styles being mainly the thrust‐fold and thrust‐monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.
A Systematic Analysis of Coal Accumulation Process
Authors: Aiguo CHENG
Published: September 2010

Abstract: Formation of coal seam and coal‐rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels: the global coal accumulation super‐system, the coal accumulation domain mega‐system, the coal accumulation basin system, and the coal seam or coal seam set sub‐system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose‐orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal‐rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis.
Origin and Superposition Metallogenic Model of the Sandstone‐type Uranium Deposit in the Northeastern Ordos Basin, China
Authors: Ziying LI , Anping CHEN , Xiheng FANG , Guangxi OU , Yuliang XIA , Ye SUN
Published: September 2010

This paper deals with the metallogenic model of the sandstone type uranium deposit in the northeastern Ordos Basin from aspects of uranium source, migration and deposition. A superposition metallogenic model has been established due to complex uranium mineralization processes with superposition of oil‐gas reduction and thermal reformation.
Typomorpic Characteristics of the Major Minerals in the Puziwan Gold Deposit, Datong, Shanxi, China
Authors: Min QING , Cuiyi NIU , Shibin LEI
Published: September 2010

Utilizing theories of minerageny and prospecting mineralogy, the authors studied the attitude, morphotype and chemical composition of metallic minerals of pyrite, gold, chalcopyrite, galena and sphalerite, non‐metallic minerals of quartz, carbonate, dolomite and rutile in the Puziwan gold deposit. The study shows the following results. (1) The mineral assemblage is complex and the species of sulfide are abundant with occurrences of sulfosalt minerals. (2) The composition in the minerals is complex and there rich micro elements, including As, Sb, Bi, Se, Te, Au, Ag, Cu, Pb, Zn, and Cr, Ni, V. The typomorphic characteristics of the association of the elements and their specific value suggest that gold mineralization is associated with shallow magmatic hydrothermal activity, the ore‐forming fluid is the mixture of abundant rising alkali magmatic water originating from the mantle or the lower crust and the descending acid atmospheric water. (3) Ankerite, Fe‐rich sphalerite, granular Ti‐rich rutile are widely distributed, which indicate great denudation depths, high mineralization temperature. The deposit is found in the middle and shallow positions of the porphyry series. The deep layers are not favorable for gold mineralization. (4) Copper minerals are rich in the ores and sulfides have high content of copper, suggesting possible porphyry‐type Cu (Au) mineralization in deep positions and the surrounding areas.
Yangshan Gold Deposit: The Largest Carlin and Carlin‐Iike Type Gold Deposit in China
Authors: Fengzeng YAN , Qiangzhi LI
Published: September 2010

Gold Headquarter of the CAPF has discovered the Yangshan super large‐scale gold deposit in Gansu Province, which is a great breakthrough of gold exploration and prospecting in Western Qinling Mountains of China. The gold resources of this deposit achieved 308 tons with increasing potentials. Preliminary geological investigations indicate that the Yangshan gold deposit is located in the intra‐continental collision orogenic belt; and the deposit was formed during the continent‐continent collision orogenic processes. The geological characteristics of the deposit are similar to that of the typical Carlin‐type gold deposits, while differences still exist. The ore‐forming background is notably different from the Carlin gold deposit province in the United States; and the ore‐forming fluids are similar with that of the orogenic‐type gold deposit. Accordingly, the Yangshan gold deposit is a transitional type between the Carlin‐type and the orogenic type gold deposits. At present, the Yangshan gold deposit is the largest Carlin and Carlin‐like type gold deposit that is ever discovered in China. Researches on metallogeny, metallogenic model and ore‐enrichment regularities of the Yangshan gold deposit are crucial to meet the pressing needs of the current geological investigation and ore exploration of the deposit.
A Preliminary Study on Fluid Inclusions and Mineralization of Xitieshan Sedimentary‐Exhalative (SEDEX) Lead‐Zinc Deposit
Authors: Lijuan WANG , Xinyou ZHU , Jingbin WANG , Jiniu DENG , Yuwang WANG , Heping ZHU
Published: September 2010

The Xitieshan lead‐zinc deposit is located at the northern margin of the Qaidam Basin, Qinghai Province, China, and had developed a complete marine sedimentary‐exhalative system. Our preliminary study of ore‐forming fluids shows that fluid inclusions in quartz from altered stockwork rocks that represent the pipe facies have a wide range of temperature and salinity. The intense fluid activities are characteristics of the pipe facies of the exhalative system. Fluid inclusions in carbonates near the unstratified ore bodies hosted in the thick‐bedded marble which represents vent‐proximal facies are large in size and have moderate to high temperatures. They represent unerupted sub‐seafloor fluid activity. Fluids in altered stockwork rocks and carbonates have similar H2O‐NaCl‐CO2 system, both belonging to the sedimentary‐exhalative system. The fluids migrate from the pipe facies to the unstratified ore bodies. Boiling of the fluids causes the separation of CO2 vapor and liquid H2O. When the fluids migrate into the unconsolidated thick‐bedded marble, the escape of CO2, decreasing temperature and pressure as well as some involvement of seawater into the fluids result in the unmixing of fluids with high and low salinity and deposition of ore‐forming materials. The two unmixed fluids were trapped in unconsolidated carbonates and the ore‐forming materials were deposited in the unconsolidated carbonates to form the sedimentary‐exhalative type unstratified ore bodies. The ore‐forming temperature of unstratified ore bodies is up to high temperature indicating that there is a huge ore‐forming potential in its deep.
Diagenesis and Metamorphism of Triassic Flysch Along Profile Zoigê‐Lushan, Northwest Sichuan, China
Authors: Hejing WANG , RAHN M. , Xiaofeng TAO , Nan ZHENG , Tingjing XU
Published: September 2010

We used illite and chlorite crystallinities, index minerals, mineral assemblages, polytype and domain size of white mica, electron microprobe analysis (EMPA), b0 geobarometer and chlorite geothermometer to quantify the diagenetic and metamorphic overprint on the Triassic flysch formations in the Songpan‐Garzê orogen along profile Zoigê‐Lushan, northwest Sichuan. Two anchizones, two epizones, one diagenetic zone and a transition belt in‐between them are defined on the basis of the obtained data. Illite crystallinity correlates strongly with the best mean domain size of mica and moderately with chlorite crystallinity. 2M1 white mica polytype are observed within the epizone whilst 2M1 and 1M polytypes occur in the anchizone and diagenetic zone. Epizonal metamorphism reached maximum temperatures of 370°C±21°C at low‐to intermediate pressure conditions. Clay minerals underwent Ostwald ripening during metamorphism. Rocks from both sides of the Longmenshan fault reveal contrasting degrees of metamorphic overprint: on the northwest side of the Longmenshan fault, epimetamorphic conditions contrast with diagenetic rocks on the southeast side.
Geochemical Mapping—Evolution of Its Aims, Ideas and Technology
Authors: Xuejing XIE
Published: September 2010

The development of geochemical mapping progressed from local geochemical prospecting through regional geochemical exploration and regional geochemical mapping to national and global geochemical mapping. This paper discusses the evolution of aims, ideas and methodology of geochemical mapping in Western countries, Russia and China. The sophistication of geochemical mapping methodology will make great contributions to solving resources and environmental problems in the 21st century.
Weathering‐pedogenesis of Carbonate Rocks and Its Environmental Effects in Subtropical Region
Authors: Lijun ZHU , Shouyang HE , Jingyang LI
Published: September 2010

We investigated the weathering‐pedogenesis of carbonate rocks and its environmental effects in subtropical regions of China. The investigation demonstrated that the weathering‐pedogenesis of carbonate rocks is the process of a joint action of corrosion and illuviation and metasomatism in subtropical region. It is characterized by multi‐stage, multi‐path and multi‐style. With the persisting development of weathering‐pedogenesis of carbonate rocks, metasomatic pedogenesis progressively became the main process of the weathering‐pedogenesis and the dominant style of formation of minerals. And it proceeds through the whole process of evolution of the weathering‐pedogenesis of carbonate rocks. The stage evolution of weathering‐pedogenesis of carbonate rocks and the fractionation evolution of newly produced minerals are characterized by obvious vertically zoning structures and the rules of gradation of elements geochemical characteristics in the carbonate rocks weathering profiles. The geochemical process of weathering‐pedogenesis of carbonate rocks can be divided into three geochemical evolution stages, i.e., the Ca, Mg‐depletion and Si, Al‐enrichment stage; the Fe, Mn enrichment stage and the Si‐depletion and Al‐enrichment stage in the subtropical regions. Consistent with the three geochemical evolution stages, the sequence of formation and evolution of minerals can be divided into the clay mineral stage; the Fe, Mn oxide and the gibbsite stage. The influence of weathering‐pedogenesis of carbonate rocks on the chemical forms of heavy elements is mainly affected via newly produced components and minerals in the process of weathering‐pedogenesis, e.g., iron oxide minerals and organic matters. The important mechanism for the mobilization, transport and pollution of F and As is affected the selective adsorption and desorption of F and As on the surface of iron oxide minerals in the subtropical karst zones, i.e., the selective adsorption and desorption on mineral surfaces of newly produced minerals in the process of weathering‐pedogenesis control the geochemical behavior of elements on the Earth's surface and environmental quality in subtropical regions.
Heavy Metal Distributions and Source Tracing in the Lacustrine Sediments of Dongdao Island, South China Sea
Authors: Xiaodong LIU , Liguang SUN , Xuebin YIN , Yuhong WANG
Published: September 2010

The levels and depth distributions of As, Cd, Cu, Zn, Pb, Hg, Fe and Mn in two sediment cores DY2 and DY4 collected from the “Cattle Pond” of Dongdao Island, South China Sea, were determined and analyzed with the main objective to identify the sources of these elements and evaluate the corresponding sedimentological and geochemical processes. Lithological characters and sedimentary parameters such as LOI950°C, CaO, LOI550°c and TOC indicate that the depth of 96 cm and 87 cm are the critical points for DY2 and DY4 cores, respectively. As, Cd, Cu, Zn, Hg and P are remarkably enriched in the ornithogenic sediments above the critical depth points; their concentration‐versus‐depth profiles are similar to those of TOC and LOI5S0 c; the ratios of As, Cd, Cu, Zn, Hg over Ca are significantly correlated with P/Ca. Statistical and comparative analyses of these elements' levels in the ornithogenic sediments of DY2 and DY4 strongly suggest that seabird droppings are the main source of these elements. Additionally, for the upper sediment layers of DY2 and DY4 cores, Fe oxide sorption mechanism, like organic matter, may also play an important role in the abundances of heavy metals. Heavy metal Pb has geochemical characteristics distinctly different from those of As, Cd, Cu, Zn, Hg and P, and its isotope composition indicates an origin of anthropogenic emissions from the surrounding countries. These geochemical characteristics in the orinithogenic sediments of Xisha Islands are compared with the studies in the remote Antarctic and Arctic regions.
Environmental Investigation and Evaluation of Land Subsidence in the Datong Coalfield Based on InSAR Technology
Authors: Xiuming JIA , Chao MA , Anyuan ZHAO
Published: September 2010

Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak. Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo‐environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D‐InSAR (differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo‐environmental investigation to ascertain the geo‐environmental background of the Datong Jurassic and Carboniferous‐Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo‐environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog‐nominal ERS‐1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multi‐temporal SAR magnitude images were used to interpret the geological structure, vegetation, microgeomorphology and drainage system; (2) the multi‐temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi‐temporal cog‐nominal SAR images were used to complete D‐InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten‐year time series of differential interferograms were obtained using the multi‐temporal cog‐nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993–1996, 1996–1997, 1997–1998, 1998–2001, 1998–2002 and 2001–2003 respectively. Of the 84 areas, 44 are mining subsidence ones, 23 urban subsidence ones and 17 landslide subsidence ones. They cover a total area of 1824.4 km2, equivalent to the area of the whole Datong coalfield. Then an accurate evaluation was made on the geo‐environment of the Datong coalfield. The tests show that InSAR is now the only feasible technical means for making one all‐weather, real‐time measurement of a coal mining land subsidence area covering up to 10,000 km2 to subcentimeter resolution. This study is a successful application of InSAR in the investigation and evaluation of land subsidence, especially in coal mining areas.
Taxonomical and Biogeochemical Investigation of Elements in Holocene Mollusk Shells in the South and Southwestern Marmara Basin, Thrkey
Authors: ALIYEV Saday Azadoĝlu , SARI Ali , ÖKTEN Bahadir
Published: September 2010

Abstract: Concentrations of some heavy metals and trace elements such as Cr, Ga, Ni, Zn, Mo, Cu, Pb, Yb, Y, Nb, Ti, Sr, Ba, Mn, Sc, Co, V, Zr, Fe, Al, W, Se, Bi, Sb, As, Cd in recent mollusk shells and factors affecting their distribution and deposits collected from various depths in the southern and southwestern parts of the Marmara Sea are investigated. The distribution of the elements in the shells is categorized into four groups. Of these, concentrations of 12 elements (As, Bi, Cd, Co, Ga, Mo, Nb, Sb, Se, Sc, W and Yb) are below zero [(0.053‐0.79)x10−6]; concentrations of seven elements (Cr, Ni, Pb, V, Y, Zr and Cu) are (1.0–6.0)x 10−6; concentrations of four elements (Ti, Mn, Ba and Zn) are 10‐20times10−6; and concentrations of five elements (Si, Al, Fe, Mg and Sr) are (47.44–268.11)x 10−6. The taxonomic characteristics of the 29 elements were studied separately in mollusk shells such as Chamalea gallina (Linné), Pitar rudis (Poli), Nassarius reticulatis (Linné), Venerupis senescens (Coocconi), Mytilus galloprovincialis (Lamarck), Mytilaster lineatus (Gemelin in Linné) and Chlamys glabra. It was found that, in mollusk taxonomy, the elements have unique values. In other words, element concentrations in various mollusk shells depend mainly on the taxonomic characteristics of mollusks. In various bionomic environments different element distributions of the same species are attributed to the different geochemical characters of the each environment. Data obtained in this study indicate that the organisms are the most active and deterministic factors of the environment.
A Comprehensive Model for Evaluating Coalbed Methane Reservoirs in China
Authors: Yanbin YAO , Dameng LIU , Dazhen TANG , Wenhui HUANG , Shuheng TANG , Yao CHE
Published: September 2010

Abstract: Coalbed methane reservoir (CBMR) evaluation is important for choosing the prospective target area for coalbed methane exploration and production. This study aims at identifying the characteristic parameters and methods to evaluate CBMR. Based on the geological surveys, laboratory measurements and field works, a four‐level analytic hierarchy process (AHP) model for CBMR evaluation is proposed. In this model, different weights are prioritized and assigned on the basis of three main criteria (including reservoir physical property, storage capacity and geological characteristics), 15 sub‐criteria, and 18 technical alternatives; the later of which are discussed in detail. The model was applied to evaluate the CBMR of the Permo‐Carboniferous coals in the Qinshui Basin, North China. This GIS‐based fuzzy AHP comprehensive model can be used for the evaluation of CBMR of medium‐high rank (mean maximum vitrinite reflectance >0.5%) coal districts in China.
ORIGINAL ARTICLE: Diagnostic immunomarkers for HepPar‐1 negative areas of hepatocellular carcinoma
Authors: Lee Tae‐Hui , Yim Hyunee , Seok Jae Yeon , Kim Young‐Bae
Published: September 2010

Background and aim: HepPar‐1 is a sensitive and specific antibody. However, when used for the diagnosis of hepatocellular carcinoma (HCC), especially in needle biopsy specimens, this diagnostic approach is limited by potential multifocal expression and/or poorly differentiated HCCs, where it may not be expressed. The goal of this study was to determine the antibodies most sensitive to hepatocyte differentiation in HepPar‐1 negative areas including: CD13, CD10, polyclonal carcinoembryonic antigen (pCEA), alpha‐fetoprotein (AFP) and glypican‐3, for needle biopsy. Methods: Fifty cases of HCCs were obtained from surgically resected livers. Immunohistochemical staining for hepatocyte and biliary markers‐ HepPar‐1, CD13, glypican‐3, pCEA, CD10, AFP, cytokeratin (CK)7, CK19, and epithelial cell adhesion molecule (EpCAM) was performed from paraffin block samples. Results: HepPar‐1 was diffusely negative in 12 cases. Twenty two cases showed partial expression of the HepPar‐1 antibody. Among 34 HepPar‐1 negative areas, CD13 was the most consistent antibody (85.3%, 29/34) showing the characteristic bile canaliculi pattern. Immunoexpression of biliary differentiation with CK7, CK19, and EpCAM showed no significant differences in HepPar‐1 negative areas. Conclusions: CD13 could be used for the detection of hepatocyte differentiation in HCCs with HepPar‐1 negative expression, especially in needle biopsy specimens. In addition, negative immunoexpression for HepPar‐1 was not overtly related to biliary differentiation, from an immunohistochemical viewpoint.
Engineering Academic Programs for Hydrophilanthropy: Commonalities and Challenges
Authors: Silliman Stephen , Mohtar Rabi H. , Paterson Kurtis G. , Ball William P.
Published: September 2010

This paper presents four different program models for student participation in international development that are being used by universities throughout the United States with a focus on international water resource projects. These include a service‐oriented program (Engineers Without Borders at Johns Hopkins University), a senior design program (Global Design Teams at Purdue University), an extended research program (Long Term Research at the University of Notre Dame), and a graduate program affiliated with the Peace Corps (The Peace Corps Master's International Program in Civil and Environmental Engineering at Michigan Technological University). Differences and commonalities are identified across the four models, as are the critical components, resources, and challenges which must often be addressed for the success of these types of projects. A major conclusion is that, regardless of the program model used for the experience, international experiences continue to have strong, positive impact on the engineering student and, when properly designed, on the in‐country stakeholders.
A Call to Action: Proposing a University Network for Water, Sanitation, and Hygiene
Authors: Laituri Melinda , Sternlieb Faith , Waskom Reagan
Published: September 2010

Water is the critical concern of countries around the world due to increasing population and environmental change. The Paul Simon Water for the World Act, passed in early 2010, aims to provide support and funding for the provision of safe water and sanitation. Universities are uniquely poised to address solutions and assessments of efforts to address water, sanitation, and hygiene (WASH). This paper outlines a “call to action” for universities to collectively address WASH issues by establishing a network that identifies experts, links resources, and builds partnerships.
Is Japan Facing a Public Debt Crisis? Debt Financing and the Development of the JGB Market
Authors: Kang Myung‐koo
Published: September 2010

This article explores the idiosyncratic institutional features of public debt financing in Japan that have enabled the government to finance increasing public debt at low costs. It examines the three key aspects that contributed to the Japanese government bond (JGB) market development: (1) the surplus financial balance of the household sector; (2) the strong tradition of public financing; and (3) home bias, that is, little dependence on external financing. It argues that Japan's financial institutions' capacity to absorb JGBs is reaching the limit and that the Japanese government needs to take bolder measures to reverse the flow of financial intermediation, from the public to the private sector. It also suggests that restoring people's trust in the government's competence and leadership is an essential element for successful fiscal consolidation.
ASEAN in the Asia Pacific: Central or Peripheral?
Authors: Amador III Julio Santiago
Published: September 2010

The Association of Southeast Asian Nations (ASEAN) is an enduring regional organization in the Asia Pacific. However, its claim of being central to any talks on regional architecture is challenged by a multiplicity of external and internal factors. This article assesses ASEAN's centrality by looking into the possible challenges facing it, which inevitably affect its claim to be the central organization in managing the direction of the wider region. It then offers possible ways forward so that ASEAN can retain its leadership and prove to be a credible driver for regional cooperation.
How the New Government Utilizes Emerging Internet Media in Japan
Authors: Matsuura Masahiro
Published: September 2010

The newly elected Hatoyama administration has launched several projects on the Internet to facilitate interactions with the public. Politicians use Twitter to tweet their political activities and interact with other users. Government agencies have launched several new Web sites, such as hatomimi and jukugi kake‐ai, and integrated video‐steaming sites, such as ustream.com. Notwithstanding these efforts, however, the new administration has not yet been able to apply these forums to resolving hard political issues.