bluuebunny/crossref_metadata_2025 huggingface dataset:
Petrology, Mineralogy and Geochemistry of the Emeishan Continental Flood Basalts, SW China: Evidence for Activity of Mantle Plumes
Authors: Zhaochong ZHANG , Yanli HAO , Fusheng WANG , MAHONEY John J.
Published: September 2010

Abstract Electronic microprobe analyses for olivine, clinopyroxene and Cr‐spinel in picrites, which we have discovered recently in the Emeishan continental flood basalt province (ECFBP), show that the olivine is rich in Mg, and that Cr‐spinel is rich in Cr. Based on the olivine‐melt equilibrium, the primary parental melt compositions are calculated. The high‐Mg olivine‐hosted picrite can be regarded as parental melt. Thus, the melting temperature and pressure are estimated: T=1600°C and P=4.5 GPa. It suggests that the picrites are connected with the activity of mantle plumes. Their major element composition is comparable to many other CFBs by their high Fe8, (CaO/Al2O3)8 and low Na8, indicating a high pressure. All rocks display a similar chondrite‐normalized REE patterns, i.e., enrichment of LREE, relative depletion of HFSE and absence of negative Nb and Ta but depletion in P and K. Some incompatible element ratios, such as La/Ta, La/ Sm, (La/Nb)pM, (Th/Ta)pM, are in a limited range, show that they were derived from the mantle plume, and there was no or little crustal contamination during magma ascent en route to the surface. They were generated by 7% partial melting of garnet peridotite. The axis of the plume might be located beneath Lijiang Town, Yunnan province.
Association of Late Paleozoic Adakitic Rocks and Shoshonitic Volcanic Rocks in the Western Tianshan, China
Authors: Zhenhua ZHAO , Xiaolin XIONG , Qiang WANG , Zhenghua BAI , Jifeng XU , Yulou QIAO
Published: September 2010

Abstract The late Paleozoic adakitic rocks are closely associated with the shoshonitic volcanic rocks in the western Tianshan Mountains, China, both spatially and temporally. The magmatic rocks were formed during the period from the middle to the late Permian with isotopic ages of 248–268 Ma. The 87Sr/86Sr initial ratios of the rocks are low in a narrow variation range (˜0.7050). The 143Nd/144Nd initial ratios are high (˜0.51240) with positive εNd(t) values (+1.28–***+4.92). In the εNd(t)–(87Sr/86Sr)i diagram they fall in the first quadrant. The association of the shoshonitic and adakitic rocks can be interpreted by a two‐stage model: the shoshonitic volcanic rocks were formed through long‐term fractional crystallization of underplated basaltic magma, while the following partial melting of the residual phases formed the adakitic rocks.
Seismic Velocity Structure and Composition of the Continental Crust of Eastern China
Authors: Yang WANG , Jiamin CAO , Jieshou ZHU
Published: September 2010

Abstract On the basis of a one‐by‐one latitude‐longitude grid three‐dimensional seismic velocity model, the crustal P‐wave velocity structure in eastern China (105–125°E and 18–41°N) is obtained, and a set of geotherms for each grid is established for P‐T correction on P‐wave velocities. The average depths of sub‐crustal layers and their average P‐wave velocities of 18 tectonic units in eastern China are exhibited. Our result presents a 32–34 km thick crust beneath eastern China, which is thinner than previous studies, with an average velocity of 6.54 km/s, corresponding to a 5 kg/m3 variation in crustal mean density. The thicker upper but thinner middle and lower crust results in a lower average seismic velocity of eastern China. An intermediate crustal composition with a SiO2 content of 59.7 wt% has been estimated. However, there exists a significant lateral variation in the crustal structures among the tectonic units of eastern China. The structure and composition features of some regions in eastern China indicate that extension has played an important role in the continental crust evolution of eastern China.
On the Origin of One Basin‐Multiple Mountain Couplings in the Mesozoic‐Cenozoic Basin‐Range Area in Eastern North China
Authors: Shuyin NIU , Ji'an SHAO , Quanlin HOU , Baode WANG , Chuanshi XU
Published: September 2010

Abstract The basin‐range coupling relation is a leading subject of the modern geology. In geometry, relations of this type include couplings between stretched orogenic belt and down‐faulted basin, compressional orogenic belt and foreland basin, strike‐slip orogenic belt and strike‐slip basin and so on. Fault chains are the key for these couplings and there are typical examples for all these cases. The North China down‐faulted basin is coupled west with the Taihang uplift, east with the Jiao‐Liao Mountains, north with the Yanshan orogenic belt and south with the Dabie orogenic belt, that is to say, the central down‐faulted basin and the surrounding orogenic belts bear a coupling relation within a uniform dynamistic system. Study shows that the central down‐faulted basin and the North China mantle sub‐plume structure have a close relation during their formation. Owing to intensive mantle sub‐plume uplifting, the bottom of the lithosphere suffered from resistance, which caused the lithosphere of the eastern North China to be heated, thinned and fault‐depressed. Meanwhile, mantle rocks that were detached outwards in the shape of mushroom was dissected by surrounding ductile shearing zones, which lead to decompression and unloading to generate hypomagmas, and a series of mantle‐branch structures were formed around the down‐faulted basin. There is an obvious comparability among these mantle branch structures (orogenic belts), and they have basin‐range coupling relations with the central down‐faulted basins.
Two‐dimensional Numerical Modeling Research on Continent Subduction Dynamics
Authors: Zhimin WANG , Bei XU , Yaoqi ZHOU , Hehua XU , Shaoying HUANG
Published: September 2010

Abstract Continent subduction is one of the hot research problems in geoscience. New models presented here have been set up and two‐dimensional numerical modeling research on the possibility of continental subduction has been made with the finite element software, ANSYS, based on documentary evidence and reasonable assumptions that the subduction of oceanic crust has occurred, the subduction of continental crust can take place and the process can be simplified to a discontinuous plane strain theory model. The modeling results show that it is completely possible for continental crust to be subducted to a depth of 120 km under certain circumstances and conditions. At the same time, the simulations of continental subduction under a single dynamical factor have also been made, including the pull force of the subducted oceanic lithosphere, the drag force connected with mantle convection and the push force of the mid‐ocean ridge. These experiments show that the drag force connected with mantle convection is critical for continent subduction.
Identification of Five Stages of Dike Swarms in the Shanxi‐Hebei‐Inner Mongolia Border Area and Its Tectonic Implications
Authors: Ji'an SHAO , Mingguo ZHAI , Lüqiao ZHANG , Daming LI
Published: September 2010

Abstract Dike swarms are generally ascribed to intrusion of mantle‐source magma result from extension. Basic dike swarms around the Shanxi‐Hebei‐Inner Mogolia borders in the northern peripheral area of the North China Craton can be divided into five age groups according to isotopic dating: 1800–1700 Ma, 800–700 Ma, 230 Ma, 140–120 Ma, and 50–40 Ma. Geological, petrological and isotope geochemical features of the five groups is investigated in order to explore the variation of the mantle material composition in the concerned area with time. And the various extensional activities reflected by the five groups of dike swarms are compared with some important tectonic events within the North China Craton as well as around the world during the same period.
Octoradiate Spiral Organisms in the Ediacaran of South China
Authors: Feng TANG , Chongyu YIN , BENGTSON Stefan , Pengju LIU , Ziqiang WANG , Linzhi GAO
Published: September 2010

Abstract: Shales of the Ediacaran Doushantuo Formation of South China contain a new disc‐shaped macrofossil, Eoandromeda octobrachiata, characterized by eight spiral arms that were probably housed within an outer membrane. Although the presence of eight radiating structures entails a resemblance to cnidarian octocorals as well as to ctenophores, direct homologies with these extant groups are unlikely. Instead we bring attention to the helicospiral morphology of newly reported embryos from the Doushantuo Formation, suggesting that the long‐sought adults of the Ediacaran embryonic metazoans have finally been found.
New Jurassic Fossil True Bugs of the Pachymeridiidae (Hemiptera: Pentatomomorpha) from Northeast China
Authors: Yunzhi YAO , Wanzhi CAI , Dong REN
Published: September 2010

Abstract: Four new fossil genera and species of true bugs from the family Pachymeridiidae, Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regillus, and Viriosinervis stolidus, are described. New specimens were collected from the Middle and Upper Jurassic non‐marine sedimentary strata from the Jiulongshan and Yixian Formations of northeast China. The species Karatavocoris asiatica Becker‐Migdisova, 1963, which was considered to be a member of the family Coreidae is transferred to the Pachymeridiidae. A new map of all known and newly discovered fossil pachymeridiid localities is given. The diagnosis of the family is modified.
Permian/Triassic Boundary and Its Correlation in the Daxian‐Xuanhan Area, Northeastern Sichuan Province, China
Authors: Yongsheng MA , Chuanlong MOU , Qinyin TAN , Qian YU , Ruihua WANG
Published: September 2010

Abstract: There are different opinions about the Permian/Triassic boundary and its correlation in the Daxian‐Xuanhan area because of lacking typical lithological symbols and fossil criterions. Especially, it is very hard to determine the Permian/Triassic boundary in the Daxian‐Xuanhan buried areas. This brings many difficulties to geological research and oil and gas exploration. Based on field investigation and studies of well cores, newly found fossils, lithological characteristics and well log analyses, the authors discussed the Permian/Triassic boundary in the Daxian‐Xuanhan area and brought forward a specific scheme for its determination and regional correlation.
Landslide Hazard and Risk Assessment on the Northern Slope of Mt. Changbai, China
Authors: Zhenghua LIU , Yanbin ZHANG , Ishikawa Yoshiharu , Nakamura Hiroyuki
Published: September 2010

Abstract: Landslide hazard and risk assessment on the northern slope of Mt. Changbai, a well‐known tourist attraction near the North Korean‐Chinese border, are assessed. This study is divided into two parts, namely, landslide hazard zonation and risk assessment. The 1992 Anbalagan and Singh method of landslide hazard zonation (LHZ) was modified and used in this area. In this way, an Associative Analysis Method was used in representative areas to get a measure for controlling factors (slope gradient, relative relief, vegetation, geology, discontinuity development, weak layer thickness and ground water). For the membership degree of factor to slope failure, the middle range of limited values was used to calculate LHZ. Based on an estimation of the potential damage from slope failure, a reasonable risk assessment map was obtained using the relationship of potential damage and probable hazard to aid future planning and prediction and to avert loss of life.
Jurassic Tectonics of North China: A Synthetic View
Authors: Yueqiao ZHANG , Shuwen DONG , Yue ZHAO , Tian ZHANG
Published: September 2010

Abstract: This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in North China have been divided into three stages. The earliest Jurassic is marked by a period of magmatism quiescence (in 205–190 Ma) and regional uplift, which are considered to be the continuation of the “Indosinian movement” characterized by continent‐continent collision between the North and South China blocks. The Early to Middle Jurassic (in 190–170 Ma) was predominated by weak lithospheric extension expressed by mantle‐derived plutonism and volcanism along the Yanshan belt and alongside the Tan‐Lu fault zone, normal faulting and graben formation along the Yinshan‐Yanshan tectonic belt, depression and resuming of coal‐bearing sedimentation in vast regions of the North China block (NCB). The Middle to Late Jurassic stage started at 165±5 Ma and ended up before 136 Ma; it was dominated by intensive intraplate deformation resulting from multi‐directional compressions. Two major deformation events have been identified. One is marked by stratigraphic unconformity beneath the thick Upper Jurassic molasic series in the foreland zones of the western Ordos thrust‐fold belt and along the Yinshan‐Yanshan belt; it was predated 160 Ma. The other one is indicated by stratigraphic unconformity at the base of the Lower Cretaceous and predated 135 Ma. During this last stage, two latitudinal tectonic belts, the Yinshan‐Yanshan belt in the north and the Qinling‐Dabie belt in the south, and the western margin of the Ordos basin were all activated by thrusting; the NCB itself was deformed by the NE to NNE‐trending structural system involving thrusting, associated folding and sinistral strike‐slip faulting, which were spatially partitioned. Foliated S‐type granitic plutons aged 160–150 Ma were massively emplaced in the Jiao‐Liao massif east of the Tan‐Lu fault zone and indicate important crustal thickening in this part of the NCB. The Jurassic deformation patterns, different tectonic systems and multi‐directional contractions in North China recorded far‐field effects of synchronous convergences, toward the East Asian continent, of three different plates, the Siberian plate in the north, the paleo‐Pacific oceanic plate in the east and the Lhasa block in the southwest. This Middle to Late Jurassic intraplate orogenesis and pervasive shortening deformation preceded lithospheric attenuation and thinning in East China, which most possibly started by the Early Cretaceous around 135 Ma.
Geochemistry and SHRIMP Zircon U‐Pb Age of Post‐Collisional Granites in the Southwest Tianshan Orogenic Belt of China: Examples from the Heiyingshan and Laohutai Plutons
Authors: Lingli LONG , Jun GAO , Jingbin WANG , Qing QIAN , Xianming XIONG , Yuwang WANG , Lijuan WANG , Liming GAO
Published: September 2010

Abstract:The Heiyingshan granite and the Laohutai granite plutons exposed in the Southwest Tianshan resemble A‐type granites geochemically. Analysis shows that the both are ferron calc‐alkalic peraluminous or ferron alkali‐calcic peraluminous with a relatively high concentration of SiO2(>70%), high alkali contents (Na2O + K2O = 7.14%‐8.56%; K2O>N2O; A/CNK = 0.99‐1.20), and pronounced negative anomales in Eu, Ba, Sr, P and Ti. A SHRIMP zircon U‐Pb age of 285±4 Ma was obtained for the Heiyingshan hornblende biotite granite intrusion. The geochemical and age dating data reported in this paper indicate that these granites were formed during the post‐collisional crustal extension of the Southwest Tianshan orogenic belt, in agreement with the published data for the granites in the South Tianshan.
Zircon LA‐ICPMS U‐Pb Age, Sr‐Nd‐Pb Isotopic Compositions and Geochemistry of the Triassic Post‐collisional Wulong Adakitic Granodiorite in the South Qinling, Central China, and Its Petrogenesis
Authors: Jiangfeng QIN , Shaocong LAI , Juan WANG , Yongfei LI
Published: September 2010

Abstract: The Indosinian post‐collisional Wulong pluton intruded into the Mesoproterozoic Fuping Group, South Qinling, central China. In the southern part of the pluton, some mafic enclaves have sharp or gradational contact relationships with the host biotite granodiorite. Geochemistry, zircon LA‐ICP MS (laser ablation inductively‐coupled plasma mass spectrometry) U‐Pb chronology and Sr‐Nd‐Pb isotope geochemistry of the pluton are reported in this paper. The biotite granodiorite shows close compositional similarities to high‐silica adakite. Its chondrite‐normalized REE patterns are characterized by strong HREE depletion (Yb = 0.33‐0.96 10−6 and Y = 4.77‐11.19 times 10−6), enrichment of Ba (775–1386 times10−6) and Sr (643–1115 × 10−6) and high Sr/Y (57.83–159.99) and Y/Yb (10.99‐14.32) ratios, as well as insignificant Eu anomalies (δEu = 0.70‐0.83), suggesting a feldspar‐poor, garnet±amphibole‐rich residual mineral assemblage. The mafic enclaves have higher MgO (4.15‐8.13%), Cr (14.79–371.31 times 10−6), Ni (20.00–224.24 times 10−6) and Nb/Ta (15.42‐21.91) than the host granodiorite, implying that they are mantle‐derived and might represent underplated mafic magma. Zircon LA‐ICP MS dating of the granodiorite yields a 206Pb/238U weighted mean age of 208±2 Ma (MSWD=0.50, 1s̀), which is the age of emplacement of the host biotite granodiorite. This age indicates that the Wulong pluton formed during the late‐orogenic or post‐collisional stage (≤242±21 Ma) of the South Qinling belt. The host biotite granodiorite displays 87Sr/86Sr = 0.7059‐0.7062, ISr = 0.7044‐0.7050, 143Nd/144Nd = 0.51236‐0.51238, εNd(t) = −2.26 to −2.66, 206Pb/204Pb = 18.099‐18.209, 207Pb/204Pb = 15.873‐15.979 and 208Pb/204Pb = 38.973‐39.430. Those ratios are similar to those of the Mesoproterozoic Yaolinghe Group in the South Qinling. Furthermore, its Nd isotopic model age (˜1.02 Ga) is consistent with the age (˜1.1 Ga) of the Yaolinghe Group. Based on the integrated geological and geochemical studies, coupled with previous studies, the authors suggest that the Wulong adakitic biotite granodiorite was probably generated by dehydration melting of the Yaolinghe Group‐like thickened mafic crust, triggered by underplating of mafic magma at the boundary of the thickened mafic crust and hot lithospheric mantle, and that the Wulong adakitic biotite granodiorite may have resulted from thinning and delamination of the lower crust or breakoff of the subducting slab of the Mianlue ocean during the Indosinian post‐collisional orogenic stage of the Qinling orogenic belt.
Geochemical Mapping: With Special Emphasis on Analytical Requirements
Authors: Xuejing XIE , Hangxin CHENG , Dawen LIU
Published: September 2010

Abstract: More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 to 1992, the International Geochemical Mapping project (Project 259 of UNESCO's IGCP Program) prepared recommendations designed to standardize geochemical mapping methods. The analytical requirements are an essential component of the overall recommendations. They included the following: 71 elements should be analyzed in future mapping projects; the detection limits of trace and ultratrace elements must be lower than the corresponding crustal abundances; and the Chinese GSD and Canadian STSD standard sample series should be used for the correlation of global data. A proposal was also made to collect 5000 composite samples, at very low sampling densities to cover the whole Earth's land surface. In 1997 an IUGS Working Group on Global Geochemical Baselines was formed to continue the work which began with IGCP 259. From 1997 up to now, new progress has been made especially in China and FOREGS countries under the aegis of this working group, including the study of suitable sampling media, development of a multi‐element analytical system, new proficiency test for selection of competent laboratories and role of wide‐spaced mapping in mineral exploration. One of the major problems awaiting solution has been the inability of many laboratories to meet the IGCP recommendations to generate high quality geochemical maps. Fortunately several laboratories in China and Europe have demonstrated an ability to meet the requirements and they will be well placed to render technical assistance to other countries.
Main Structural Styles and Deformation Mechanisms in the Northern Sichuan Basin, Southern China
Authors: Liangjie TANG , Tonglou GUO , Wenzheng JIN , Yixin YU , Rufeng LI
Published: September 2010

Abstract: The Triassic Jialingjiang Formation and Leikoupo Formation are characterized by thick salt layers. Three tectono‐stratigraphic sequences can be identified according to detachment layers of Lower‐Middle Triassic salt beds in the northern Sichuan Basin, i.e. the sub‐salt sequence composed of Sinian to the Lower Triassic Feixianguan Formation, the salt sequence of the Lower Triassic Jialingjiang Formation and Mid‐Triassic Leikoupou Formation, and the supra‐salt sequence composed of continental clastics of the Upper‐Triassic Xujiahe Formation, Jurassic and Cretaceous. A series of specific structural styles, such as intensively deformed belt of basement‐involved imbricated thrust belt, basement‐involved and salt‐detached superimposed deformed belt, buried salt‐related detached belt, duplex, piling triangle zone and pop‐up, developed in the northern Sichuan Basin. The relatively thin salt beds, associated with the structural deformation of the northern Sichuan Basin, might act as a large decollement layer. The deformation mechanisms in the northern Sichuan Basin included regional compression and shortening, plastic flow and detachment, tectonic upwelling and erosion, gravitational sliding and spreading. The source rocks in the northern Sichuan Basin are strata underlying the salt layer, such as the Cambrian, Silurian and Permian. The structural deformation related to the Triassic salt controlled the styles of traps for hydrocarbon. The formation and development of hydrocarbon traps in the northern Sichuan Basin might have a bearing upon the Lower‐Middle Triassic salt sequences which were favorable to the hydrocarbon accumulation and preservation. The salt layers in the Lower‐Middle Triassic formed the main cap rocks and are favorable for the accumulation and preservation of hydrocarbon.
Characteristics of Triassic Petroleum Systems in the Longmenshan Foreland Basin, Sichuan Province, China
Authors: Shixiang WU , Zhijun JIN , Liangjie TANG , Zhenrui BAI
Published: September 2010

Abstract: The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low‐porosity, low‐permeability, small pore throat, high water saturation, and strong heterogeneity. The existence of abnormally high pressure and various reservoir‐cap combinations developed at different times provide favorable conditions for trapping oil and gas. Taking the theory of petroleum systems as a guide, and beginning with research on tectonics, sedimentary history, distribution and evolution of source rocks, reservoir evolution, hydraulic force distribution, and hydrocarbon migration, analysis and study of static factors like source rocks, reservoirs and cap rocks, and dynamic factors such as hydrocarbon generation, migration, and accumulation revealed the characteristics of the Upper Triassic petroleum system in western Sichuan province. The deep‐basin gas in the central hydrocarbon kitchen of the Upper Triassic, structural‐lithological combination traps on the surrounding slopes, and the structural traps of the Indo‐Chinese‐Yangshan paleohighs, are potential plays. The relatively well‐ developed fault zones in the southern segment of the Longmengshan foothill belt are favorable Jurassic gas plays. Pengshan‐Xinjin, Qiongxi, and Dayi are recent exploration targets for Jurassic oil/gas reservoirs.
Successor Characteristics of the Mesozoic and Cenozoic Songliao Basins
Authors: Zhongquan LI , KUSKY Timothy , Danlin YING , Xiaoyu GUO , Hongkui LI
Published: September 2010

Abstract: The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous‐Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic‐Mid Jurassic Paleo‐foreland basin, the Late Jurassic‐Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin (since the Denglouku Group). This paper presents a systematic study of the basin‐mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic‐early Middle Jurassic paleo‐foreland basin fills a Triassic‐early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo‐foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic‐Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic‐early Middle Jurassic paleo‐foreland basin plays an important role both for deep natural gas exploration and the study of basin‐mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.
Geologic Features of the Petroleum ‐ rich Sags in the Bohai Bay Basin
Authors: Jiayu NIU , Wenzhi ZHAO , Caineng ZOU , Lingzhi JIANG
Published: September 2010

Abstract: More than 40 years have been passed since exploration and development of oil‐gas began in the Bohai Bay Basin. Though we have faced with many difficulties during our exploration, exciting discoveries in petroleum‐rich sags have been made in recent years. Studies show that the petroleum‐rich sags are characterized by multiple sets of oil‐gas accumulation in the pre‐Eogene to Neogene strata in profile and large‐area connection or superimposition of oil‐gas reservoirs in different strata. Therefore, petroleum‐rich sags continue to be a focus of future oil‐gas exploration in the Bohai Bay Basin. There is still a great potential of petroleum resources. Inshore and offshore areas, onshore stratigraphic reservoirs, high‐precision exploration in old oilfields, reservoirs inside buried hills, and volcanic reservoirs will contribute a lot in increasing the annual oil‐gas production and reserves in the basin.
Using Geochemical Method to Distinguish Lateral Migration and Vertical Migration in Rifted Basin: A Case Study from Eastern Lujiapu Depression in the Kailu Basin, NE China
Authors: Shuqing ZHOU , Haiping HUANG , Yuming LIU
Published: September 2010

Abstract: Migration fractionation diagnosis is complicated in rifted basins where migration distance is generally short and lateral migration in sandy beds and vertical migration along faults are co‐existed. Quantitative data from GC‐MS analysis makes it possible to distinguish lateral and vertical migration effects. Oils discovered from the Jiaolige oilfield, eastern Lujiapu Depression are derived from single source rock with similar maturity, which is an ideal case to study the migration fractionation effects. Compositional differences among oils are largely caused by the migration fractionation either laterally in sand beds or vertically along the faults. Subtle maturity differences are assessed by the classic saturated hydrocarbon parameters which have certain influence on nitrogen compounds. In a certain maturity range, the ratios of shield and semi‐shield isomers to the exposed isomers of alkylcarbazoles change with maturity in an opposite direction with migration fractionation, which may conceal the migration influence. However, migration and maturation have the same effects on absolute concentrations of alkylated carbazoles and benzocarbazole [a]/([a]+[c]) ratios, which provides an ideal tool for migration direction assessment. Continuous variations among different samples reflect increased migration distance in sandy beds, while abrupt changes may indicate the change of migration conduit systems. Integrated both geochemical interpretation and geological constrains, not only migration direction can be determined, but also the conduit systems through the sandy beds or the faults can be recognized.
Uranium Potential and Regional Metallogeny in China
Authors: Jindai ZHANG , Ziying LI
Published: September 2010

This paper is briefly involved in distributions of China's uranium metallogenic types, provinces, regions and belts. Eight target regions have been pointed out to be worthy of prospecting for uranium resources. The regional uranium metallogeny is discussed and great uranium potential pointed out from many aspects. Generally speaking, there are favorable conditions for uranium mineralization and good perspective to explore for uranium resources.
Geology and Genesis of the Superlarge Jinchang Gold Deposit, NE China
Authors: Guozhi JIA , Jinrong CHEN , Zhaoguang YANG , Hongye BIAN , Yangzhong WANG , Haijun LIANG , Tonghe JIN , Zhenhui LI
Published: September 2010

The superlarge Jinchang gold deposit is located in the joint area between the Taipingling uplift and the Laoheishan depression of the Xingkai Block in both eastern Jilin and eastern Heilongjiang Province. Wall rocks of the gold deposits are the Neoproterozoic Huangsong Group of metamorphic rocks. Yanshanian magmatism in this region can be divided into 5 phases, the diorite, the graphic granite, the granite, the granite porphyry and the diorite porphyrite, which resulted in the magmatic domes and cryptoexplosive breecia chimney followed by large‐scale hydrothermal alteration. Gold mineralization is closely related to the fourth and fifth phase of magmatism. According to the occurrences, gold ores can be subdivided into auriferous pyritized quartz vein, auriferous quartz‐pyrite vein, auriferous polymetallic sulfide quartz vein and auriferous pyritized calcite vein. The ages of the gold deposit are ranging from 122.53 to 119.40 Ma. The ore bodies were controlled by a uniform tectono‐magmatic hydrothermal alteration system that the ore‐forming materials were deep derived from and the ore‐forming fluids were dominated by magmatic waters with addition of some atmospheric water in the later phase of mineralization. Gold mineralization took place in an environment of medium to high temperatures and medium pressures. Ore‐forming fluids were the K+‐Na+‐Ca2+‐Cl−‐SO42‐ type and characterized by medium salinity or a slightly higher, weak alkaline and weak reductive. Au in the ore‐forming fluids was transported as complexes of [Au (HS)2]−, [AuCl2]−, [Au(CO2)]− and [Au(HCO3)2]−. Along with the decline of temperatures and pressures, the ore‐forming fluids varied from acidic to weak acidic and then to weak alkaline, which resulted in the dissociation of the complex and finally the precipitation of the gold.
The Structure of Ore‐controlling Strain and Stress Fields in the Shangzhuang Gold Deposit in Shandong Province, China
Authors: Jun DENG , Qingfei WANG , Liqiang YANG , Lei ZHOU , Qingjie GONG , Wanming YUAN , Hao XU , Chunying GUO , Xiangwei LIU , Xiling Edited By Zhu
Published: September 2010

The Shangzhuang altered‐rock type gold ore deposit is located in the middle segment of and controlled by the Wang'ershan fault zone in the northwestern part of the Jiaodong gold province, China. The deformation evolution, the structure of strain and stress fields and its ore‐controlling effect in the Shangzhuang deposit are discussed in this paper. It is revealed that the deformation evolution has mainly undergone four phases: the early ductile deformation, the second NE‐striking horizontal simple shear, the third NE‐striking compression‐shear and the final NW‐striking compression. The mineralization happened during the third stage in which the maximum principal stress gradually transited from NE to NW. The 3‐D numerical simulations of the stress field show that, on the condition that the maximum principal stress is NE‐striking, the fracture development in the fault zone is favored, while when the maximum principal stress is NW‐striking, the fault zone is relatively extensional and it is suitable for the influx and emplacement of ore‐forming fluids. The compression‐shear strain field during the mineralization is characterized by the Λ‐type structure, the positive flower structure, etc. Orebodies are mostly equidistantly located in the dilatational spaces, which are distributed in the integral compressional circumstances. And the dilatational spaces are developed where the fault attitude changes or shear joint systems develop. In the overall compression‐shear stress field, the strain field bears self‐similarity at multiple scales, including the orebody, ore deposit and orefield. The self‐similarity of the structure comprises the subequidistant distribution of fractures at the same scale and the similar shape of the fractures at various scales. Yet, due to the special geological structure, the orebodies are mostly located in the hanging wall in the Shangzhuang deposit, which is different from most deposits in the Jiaodong gold province. Analyses of the ore‐controlling stress and strain fields in the deposit provide an important basis for deposit seeking.
Isotopes and Geochronology of the Meixian‐type Pb‐Zn‐(Ag) Deposits, Central Fujian Rift, South China: Implications for Geological Events
Authors: Chengyou FENG , Dequan ZHANG , Daxin LI , Hongquan SHE , Yingjun DONG
Published: September 2010

Central Fujian Rift is another new and important volcanogenic massive sulfide Pb‐Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian‐type Pb‐Zn‐Ag deposits, S and Pb isotope analysis and isotope geochronology of ores and wall rocks for five major deposits are discussed. It is concluded that the composition of sulfur isotope from sulfide ore vary slightly in different deposits and the mean value is close to zero with the δ34S ranging from −3.5%‰ to +5.6%‰ averaging at +2.0‰, which indicates that the sulfur might originate from magma or possibly erupted directly from volcano or was leached from ore‐hosted volcanic rock. The lead from ores in most deposits displays radioactive genesis character (206Pb/204Pb>18.140, 207Pb/204Pb>15.584, 208Pb/204Pb>38.569) and lead isotope values of ores are higher than those of wall rocks, which indicates that the lead was likely leached from the ore‐hosted volcanic rocks. Based on isotope data, two significant Pb‐Zn metallogenesis are delineated, which are Mid‐ and Late‐Proterozoic sedimentary exhalative metallogenesis (The single zircon U‐Pb, Sm‐Nd isochronal and Ar‐Ar dating ages of ore‐hosted wall rocks are calculated to be among 933–1788 Ma.) and Yanshanian magmatic hydrothermal superimposed and alternated metallogenesis (intrusive SHRIMP zircon U‐Pb and Rb‐Sr isochronal ages between 127–154 Ma).
Selenium and Sulfur Systematics of Mafic Dykes in Western Fujian Province, Southern China
Authors: Haifeng FAN , Hanjie WEN , Guishan ZHANG , Ruizhong HU
Published: September 2010

Fifteen samples from three study areas (the Bancun diabase dykes, the Bali hornblende gabbro dykes, the Linzifen gabbro‐diabase dykes) were collected and analyzed for selenium (Se), sulfur (S), copper (Cu), major and trace elements. In general, Se, S and Cu do positively correlate to each other. The concentration of S and Se and the S/Se ratio are higher than the corresponding value of primitive mantle (PM), and the Cu/S ratio falls in a narrow range (0.04–0.29), which is consistent with that of primitive mantle (0.05–0.20). The Bancun diabase dykes and the Bali hornblende gabbro dykes were located in an intraplate environment during the Late Mesozoic. Oceanic subduction was closely related to magmatic activities. The magmatic activities play an important role in the transportation mechanism of Se and S. Because those two groups were closer to fault zones, which may affect the distribution of S and Se and other elements. In the two groups, no crustal contamination was observed, indicating that all analyzed elements may come from enriched mantle metasomtism associated with slab subduction. However, the Linzifen gabbro‐diabase dykes were located in an intraplate rift environment, and its invading age is older than the other two groups, the primitive magma comes from mantle, and there is an anomalous relation between S, Se and Al2O3, (La/Sm)N, and all these factors could result in higher S and Se concentration.
Surface Rupture and Co‐seismic Displacement Produced by the Ms 8.0 Wenchuan Earthquake of May 12th, 2008, Sichuan, China: Eastwards Growth of the Qinghai‐Tibet Plateau
Authors: Shuwen DONG , Yueqiao ZHANG , Zhenhan WU , Nong YANG , Yinsheng MA , Wei SHI , Zhengle CHEN , Changxing LONG , Meijian AN
Published: September 2010

An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China, on May 12th, 2008 and resulted in long surface ruptures (>300 km). The first‐hand observations about the surface ruptures produced by the earthquake in the worst‐hit areas of Yingxiu, Beichuan and Qingchuan, ascertained that the causative structure of the earthquake was in the central fault zones of the Longmenshan tectonic belt. Average co‐seismic vertical displacements along the individual fault of the Yingxiu‐Beichuan rupture zone reach 2.5‐4 m and the cumulative vertical displacements across the central and frontal Longmenshan fault belt is about 5–6 m. The surface rupture strength was reduced from north of Beichuan to Qingchuan County and shows 2–3 m dextral strike‐slip component. The Wenchuan thrust‐faulting earthquake is a manifestation of eastward growth of the Tibetan Plateau under the action of continuous convergence of the Indian and Eurasian continents.
Late Cenozoic Geology and Paleo‐environment Change in the Eastern Edge of Qinghai‐Xizang Plateau
Authors: Zhizhong ZHAO , Yansong QIAO , Shubing WANG , Haitao YAO , Yan WANG , Chaozhu LI , Jianli FU , Zongxiu LIU , Mingze LI , Qi MIAO , Fuchu JIANG
Published: September 2010

There are late Cenozoic lacustrine deposits and loess and red clay and moraines in eastern edge of the Qinghai‐Xizang Plateau. Various genetic sediments recorded rich information on late Cenozoic paleo‐environment changes. Xigeda lacustrine formed during 4.2 Ma B.P.‐2.6 Ma B.P. There were 9 periodic warm‐cold alternations. Eolian deposition in western Sichuan began at 1.15 Ma B.P. The loess‐soil sequences recorded successively 14 paleo‐monsoon climate cycles. Laterite in Chengdu plain recorded 5 stages of paleoclimatic stages since 1.13 Ma B.P. There was an old glacial period of 4.3 Ma B.P. in eastern Qinghai‐Xizang Plateau. During Quaternary, there are 5 extreme paleoclimatic events corresponding with 5 glaciations.
δ13 C‐δ18 O Covariance: An Effective Indicator of Hydrological Closure for Lakes?
Authors: Jing'an CHEN , Fushun WANG , Guojiang WAN , Degui TANG , ZHANG David Dian , Ronggui HUNAG , Jian LI , Tangfu XIAO
Published: September 2010

The correlation between the δ13 C and δ18 0 in primary carbonates is affected by several factors such as hydrological balance, total CO2 concentrations, climatic condition and lake productivity. The influence of these factors on the δ13 C‐δ18 0 correlation may be different on different time scales. In this paper, two different‐type lakes in southwestern China, Lake Erhai and Lake Chenghai, are selected to investigate the influence of climatic pattern on the δ13 C‐δ18 0 correlation and to evaluate the reliability of the δ13 C‐δ18 0 covariance as an indicator of hydrological closure. The results show that there exists good correlation between the δ13 C and δ18 0 in Lake Erhai (overflowing open lake) and in Lake Chenghai (closed lake). This suggests that the δ13 C‐δ18 0 covariance may be not an effective indicator of hydrological closure for lakes, especially on short time scales. On the one hand, a hydrologically open lake may display covariant δ13 C and δ18 0 as a result of climatic influence. The particular alternate warm‐dry and cold‐wet climatic pattern in southwestern China may be the principal cause of the δ13 C‐δ18 0 covariance in Lake Erhai and Lake Chenghai. On the other hand, a hydrologically closed lake unnecessarily displays covariant trends between δ13 C and δ18 O because of the buffering effect of high CO2 concentration on the δ13 C shift in hyper‐alkaline lakes. We should be prudent when we use the covariance between δ13 C and δ18 O to judge the hydrological closure of lake.
The Role of Fracture Structure in Leachate Pollution at Landfills: A Case Study of a Landfill in Chongqing City
Authors: Yunju LUO , Dongyan LIU , Xiulan LI , Zhengwei ZHU
Published: September 2010

This paper studies a landfill where there are three faults running through. As serious pollution has occurred to the geological environment, the landfill is to be closed up and renovated. The paper aims to explore the role of fracture structure in leachate pollution at the landfill. The research was carried out in several stages. First, mathematical models of the pre‐renovation landfill with three faults running through and the landfill after renovation were established. And then, the boundary conditions and parameters of the two mathematical models were determined. The groundwater level of the landfills was simulated in order to modify the two mathematical models. As a result, a feasible mathematical model was achieved. Based on this model, a comparison was made of the COD concentration variations in the inside leachate and outside leachate between the two landfills. Accordingly, the impacts of the fracture structure on the pollution of leachate at the landfills could be identified. The study results show that while faults contribute to the migration of leachate, they also serve as a confluence of leachate, thus further deteriorating the environment. The COD concentrations of the inside leachate and the outside leachate of the pre‐renovation landfill are respectively 800 mg/L and 220 mg/L higher than those of the post‐renovation landfill. Therefore, measures must be taken to handle the leachate seepage in areas where there are faults as well as the neighboring areas so as to get the environmental pollution under control.
Numerical Modelling of Dissolving and Driving Exploitation of Potash Salt in the Qarhan Play a—A Coupled Model of Reactive Solute Transport and Chemical Equilibrium in a Multi‐component: Underground Brine System
Authors: Wenpeng LI , Zhenying LIU
Published: September 2010

Firstly, the macroscopic chemical equilibrium state of a series of chemical reactions between intercrystal brine and its media salt layer (salt deposit) in Qarhan Salt Lake was studied by using the Pitzer theory. The concept of macroscopic solubility product and its relation with accumulated ore dissolving ratio were presented, which are used in the numerical model of dissolving and driving exploitation of potassium salt in Qarhan Salt Lake. And secondly, with a model forming idea of transport model for reacting solutes in the multi‐component fresh groundwater system in porous media being a reference, a two‐dimensional transport model coupled with a series of chemical reactions in a multi‐component brine porous system (salt deposits) was developed by using the Pitzer theory. Meanwhile, the model was applied to model potassium/magnesium transport in Qarhan Salt Lake in order to study the transfer law of solid and liquid phases in the dissolving and driving process and to design the optimal injection/abstraction strategy for dissolving and capturing maximum Potassium/Magnesium in the mining of salt deposits in Qarhan Salt Lake.
New Isophlebioid Dragonflies from the Middle Jurassic of Inner Mongolia, China (Insecta: Odonata: Isophlebioptera: Campterophlebiidae)
Authors: Binglan ZHANG , Dong REN , Hong PANG
Published: September 2010

Abstract: Three new species of fossil dragonflies assigned to Sinokaratawia Nel, Huang and Lin in family Campterophlebiidae, i.e. S. daohugouica sp. nov., S. magica sp. nov. and S. gloriosa sp. nov., and new materials of male S. prokopi Nel, Huang and Lin, 2007 are described from the Middle Jurassic of Daohugou, Inner Mongolia, China. An emended diagnosis of genus Sinokaratawia was proposed.
A New Report of Serpentinites from Northern Central Indian Ridge (at 6°S)—An Implication for Hydrothermal Activity
Authors: RAY Dwijesh , BANERJEE Ranadip , IYER Sridhar D. , MUKHOPADHYAY Subir
Published: September 2010

Abstract:Serpentinites from the inside corner high (6°38.5′S/68°19.34′E) from the Northern Central Indian Ridge (NCIR) are comprised mainly of high Mg‐rich lizardite and chrysotile pseudomorphs with varying morphologies. ‘Mesh rim’, ‘window’, ‘hourglass’ and ‘bastite’ are the most common textures displayed by both chrysotile and lizardite. Numerous chrysotile veins in association with cross cutting magnetite veins indicate an advanced stage of serpentinisation. The relatively high abundance of chrysotile and lizardite suggest their close association and formation at a temperature below 250°C. Abundant ‘mesh rim’ and ‘bastite’ texture and variegated matrix reveal that the present serpentinites might have formed due to the interaction of harzburgite and seawater. Positive Eu anomaly (Eu/Eu*up to +3.38), higher La/Sm (up to 4.40) and Nb/La (up to 6.34) ratios suggest substantial hydrothermal influence during the formation of the serpentinites.
ORIGINAL ARTICLE: Expression pattern of glypican‐3, HSP70, and glutamine synthetase in chronic hepatitis B and hepatocellular carcinoma
Authors: Kim Soo Hee , Lee Kyoung Bun , Kwon Hyeong‐Ju , Jang Ja‐June
Published: September 2010

Background and aim: The three‐panel marker, glypican‐3, HSP70 and glutamine synthetase, is helpful for making a diagnosis of early hepatocellular carcinoma. To further characterize the diagnostic values of these three markers, we performed immunostaining studies in non‐neoplastic hepatocytes (chronic hepatitis B) and hepatocellular carcinoma. Methods: Immunostaining was performed for all three markers. The cases were 60 needle biopsies of chronic hepatitis B (30 with low‐grade activity and 30 with high‐grade activity) and 40 hepatocellular carcinomas (HCCs). Results: Glypican‐3 staining was detected in only one of the 60 chronic hepatitis B cases, and this case expressed moderate immunoreactivity for glypican‐3 and showed high‐grade inflammatory activity. HSP70 expression was not observed in any cases. Glutamine synthetase was strongly immunoreactive at peri‐venular hepatocytes with cytoplasmic staining in all cases. These findings reflected a normal expression pattern. On the other hand, all three markers were positive in 15 (37.5%) HCCs. At least two of three markers were positive in 26 (65.0%). Moreover, all three markers were negative in 2 (5.0%) HCCs. Conclusions: The combination of these three markers is highly specific for detecting hepatocellular carcinoma. However, caution should be exercised because non‐neoplastic hepatocytes in chronic hepatitis B with high necro‐inflammatory activity tend to show focal positivity for glypican‐3. Also we emphasize that all three markers can show negative immunoreactivity in HCC.
Student Volunteer Opportunities in Hydrophilanthropy: The Steps to Organizing a Successful Project
Authors: Fitzgerald Cathleen M.
Published: September 2010

University students who travel internationally become de facto ambassadors not only of their country but also of their universities and colleges. Therefore, it is important that all hydrophilantropy projects include awareness of cross‐cultural differences and include community participation and involvement during the early planning stages. Schedules should not be so ambitious that the project cannot be completed in the allotted time period and multiple trips to the same community are essential to assess the effectiveness and sustainability of completed projects. Low‐tech water supply technologies that are affordable, easily replicable, and require minimal or no outside monetary assistance are the keys to completion of a successful project.