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Study on lithogeochemistry of Middle Jurassic basalts from southern china represented by the Fankeng basalts from Yongding of Fujian Province

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Science china Earth Sciences 2006年第10期49卷 1020-1031页

作者： ZHOU Jincheng1.2. JIANG Shaoyong1.2. {2. Xiaolei1.2. YANG Jinghong 1.2.& ZHANG Mengqun 3.1. State Key Laboratory of Mineral Deposit Research, {1. university, nanjing 2.0093. china 2. Department of Earth Sciences, {1. university, nanjing 2.0093. china 3. Modern Analysis Center, {1. university, nanjing 2.0093. china State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing China Department of Earth Sciences Nanjing University Nanjing China Modern Analysis Center Nanjing University Nanjing China

There exists an E-W trending Middle Jurassic volcanic zone in southern china. The Fankeng basalts in the Yongding basin of Fujian Province are considered to be a typical example. The Fankeng basalts have TiO2.contents in the range of 1.92.-3.2.1}. They are classified as high-Ti basalts. They also have higher total Fe (averaging FeO* = 1..09%). The Middle Jurassic Fankeng basalts from southwestern Fujian have obvious distinctive lithogeochemical features from early Cre- taceous basalts from southeastern coast of china. They have higher HFSE, such as Th, Nb, Ta, Zr and Ti. Their element ratios related with HFSE, such as Zr/Ba, La/Nb, La/Ta ,Zr/Y, Ti/Y, Ba/Nb, K/Ti and Rb/Zr are similar to those of OIB. The most samples have ε Nd(T) of-0.70-0.2., which are near chondrite. Some samples have higher ε Nd(T) of ***, these basaltic magmas might be derived from depleted asthenospheric mantle. The lithogeochemical characteristics of the Fankeng basalts may be caused by interaction between asthenosphere and lithosphere at the time. The (Early-) Middle Jurassic basalts and gabbros from southeastern Hunan, southern Jiangxi and northern Guangdong provinces show similar geochemical features to those of the Fankeng basalts from the Yongding of Fujian. Occurrence of these OIB-type basalts in the area may be regarded as the petrological mark of upwelling of asthenosphere at the time. Upwelling of asthenosphere has led to tectonic extension and the formation of rifted basin in the area.

关键词： interaction between asthenosphere and lithosphere, lithogeochemistry, basalts, Middle Jurassic, southern china.

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Nitrogen isotopic geochemical characteristics of crude oils in several basins of china

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Science china Earth Sciences 2005年第8期48卷 1211-1219页

作者： CHEN Chuanping1.2. MEI Bowen1.& CAO Yacheng3.1. Jianghan Petroleum university, Jingzhou 43.1.0, {1. 2. Huazhong university of Science and Technology, Wuhan 43.047, {1. 3. nanjing Institute of Soil Science, Chinese Academy of Sciences, nanjing 2.0}008, {1. Jianghan Petroleum university Jingzhou China Huazhong university of Science and Technology Wuhan China nanjing Institute of Soil Science Chinese Academy of Sciences Nanjing China

Nitrogen isotopic ratios of crude oils with different physical and chemical properties in several basins of china have been measured and their geochemistry has been studied ele-mentally combined with molecular organic geochemistry methods. The data indicate that δ 1.N is in the range of ?6‰-2.‰. They vary with the oils in different sedimentary types of basins. The oils forming in the limnic environment have lower δ 1.N with the value of about 1.-5‰ whereas the oils in saline or semi-saline environment have higher δ 1.N, with most samples being above 1.‰ and some exceeding 1.‰. The average nitrogen isotopic ratio of oils from the Ordovician formation in the Tarim Basin is the lowest, with most samples having δ 1.N below zero, which reflects possibly the characteristic of the oils originating mainly from the organic matter formed in marine carbonate sedimentary environment. The δ 1.N distribution can be altered by fractionation. It increases obviously because of biodegradation and decreases during hydrocarbon migration. However, the effect of nitrogen isotopic fractionation in the short distance migration is uncon-spicuous.

关键词： nitrogen isotope, crude oil, sedimentary environment, isotopic fractionation, china.

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Effect of climatic change on snowmelt runoffs in mountainous regions of inland rivers in Northwestern china

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Science china Earth Sciences 2006年第8期49卷 881-888页

作者： wang Jian1.& LI Shuo2.1. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 73.000, {1. 2. College of Geography, nanjing Normal university, nanjing 2.1}097, {1. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences College of Geography Nanjing Normal University

Climatic change has significant impacts on snow cover in mid-latitude mountainous re- gions, in the meantime, spatial and temporal changes of snow cover and snowmelt runoffs are con- sidered as sensitive indicators for climatic change. In this study, the upper Heihe Watershed in the Qilian Mountains was selected as a typical area affected by snow cover and snowmelt runoffs in northwestern china. The changes in air temperatures, precipitation, snowfall and spring snowmelt runoffs were analyzed for the period from 1.56 to 2.01. The results indicate that climatic warming was apparent, particularly in January and February, but precipitation just fluctuated without a clear trend. The possible changes of snowmelt runoffs in the upper Heihe watershed in response to a warming of 4℃ were simulated using Snowmelt Runoff Model (SRM) based on the degree-day factor algorithm. The results of the simulation indicate that a forward shifting of snow melting season, an increase in water flows in earlier melting season, and a decline in flows in later melting season would occur under a 4℃ warming scenario.

关键词： climatic changes, snowmelt runoff, SRM model, upper Heihe Watershed, simulating.

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Application of ERS-1.scatterometer data to studying land surfaces ──Distributive characteristic of backscattering coefficient over china land surfaces

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Chinese Science Bulletin 1998年第23期43卷 1950-1955页

作者： wang Xiangyun 1. wang Chao {3. GUO Huadong {3.and SHI Yangshen 1.1. Department of Earth Sciences, nanjing university, nanjing 2.0093. china {3. Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 1.01.1. china Department of Earth Sciences Nanjing University Nanjing 210093 China Inst. of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China

ERS 1.WSC data were obtained by international cooperation. The distributive characteristics of radar backscattering coefficient image of china land surface are analyzed and the research results are presented. The capability of ERS 1.WSC data for monitoring land surfaces is investigated. The results show that the radar backscattering coefficient images can reveal the natural landform features of china land. Using the WSC data can discriminate six types of major land coverage, including evergreen vegetation and snow covered region, vegetation and crops, mountains, grassland, desert and grassland, desert. On the whole, the radar backscattering coefficient image of china land is the synthesis of the vegetation map and terrain map. Statistical study of the typical terrain shows that the radar backscatter coefficients of china land range from -2. dB to -5 dB. The lowest value corresponds to the deserts of Badain Jaran, Takla Makan, and Tengger. The highest value corresponds to snow covered regions of Himalaya Mountains and Tianshan Mountains.

关键词： ERS 1 WSC radar backscattering coefficient land surfaces coverage.

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Sorption behavior of U(VI), ^(2.4)U(VI) and ^(2.8)U(VI) onto fracture-filling clays in Beishan granite, Gansu: Application to selecting the site of high-level radwaste repository in china

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Science china Earth Sciences 2005年第10期48卷 1649-1655页

作者： MIN Maozhong1,2. LUO Xingzhang3. wang Ju4, JIN Yuanxin4 & wang Rucheng1 1. Department of Earth Sciences, State Key Laboratory of Mineral Deposit Research, {2. university, nanjing 2.0093. china 2. Center of Materials Analysis, {2. university, nanjing 2.0093. china 3. Department of Environmental Science and Engineering, {2. university, nanjing 2.0093. china 4. Beijing Geology Institute, Nuclear Industry, Beijing 10002., china nanjing {1. Nuclear Industry

The first results of sorption experiments of U(VI), 2.4U(VI) and 2.8U(VI) onto original (unpurified) fracture-filling clays from No.1.monzonitic granite intrusion, Beishan area, Gansu Province, {3. are reported. The monzonitic granite intrusion is a potential location for a high-level radwaste (HLW) repository in {3.. The present experimental results show that the maximum U(VI) sorption reached 92. at near-neutral pH and the distribution coefficient (Kd) was 1.2. mL/g. A high sorption capacity of the fracture-filling clays in host rock on radioactive ele-ments is necessary for HLW deep geological disposal repository. No preferential sorption of 2.4U onto the clays was found. Finally, the sorption of U(VI) onto the clays was also modeled using a surface complexation model.

关键词： HLW geological disposal repository, granite, uranium, radionuclide, clay, sorption.

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Distribution characteristics of terrestrial heat flow density in Jiyang depression of Shengli Oilfield, East china

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Science china Earth Sciences 2004年第9期47卷 804-812页

作者： GONG Yuling1.2. wang Liangshu1. LIU Shaowen1. LI Cheng1. HAN Yongbing1. LI Hua1. LIU Bo1.& CAI Jingong3.1. Department of Earth Sciences, {1. university, nanjing 2.0093. china 2. Department of Exploration and Information Technology of East {12. Institute of Technology, Fuzhou 3.4000, {12. 3. Earth Science Institution of Shengli Oilfield, Dongying 2.701., {12. Department of Earth Sciences Nanjing University Nanjing China Department of Exploration and Information Technology of East china Institute of Technology Fuzhou China Earth Science Institution of Shengli Oilfield Dongying China

Based on the geo-temperature data of 1. systematically continuous temperature log curves and 700 testing oil boreholes in Jiyang depression, Shengli Oilfield, and the measured thermal conductivities of 47 rock samples, the terrestrial heat flow densities of 1.4 boreholes of Jiyang depression and its surrounding areas are determined, including 1. of those data derived from systemically continuous temperature logging. The results show that Jiyang depression has a relatively high background heat flow with an average value (65.8 5.4) mW/m{3. The lateral variation of heat flow in basin has negative correlation with basement depth. Moreover, heat flow of uplift areas with shallower basement is high, so are those of regions with volcanic rocks, and those of depression areas with deep basement are relatively low. The heat flow densities of different structural units of Jiyang depression can be summarized as follows: The average heat flow value of Zhanhua sag is (67.4 5.3. mW/m{3. higher than that of the whole basin, that of Dongying sag is (66.0 6.1. mW/m{3. and that of Chezhen sag is (65.1.3.7) mW/m{3. It is apparent that these latter two values are approximate to the average value of the whole Jiyang depression, while the average value of Huimin sag is (63.65.0) mW/m{3. lower than that of the whole basin. In fact, the basement depth and the distribution framework of uplift and depression areas are all controlled by the process of lithosphere extension. In addition, the distribution of volcanic rocks in basin is also relatively close to this extension geodynamic process. In summary, the distribution characteristics of terrestrial heat flow of Jiyang depression is determined by the Cenozoic tectono-thermal events of this region.

关键词： Jiyang depression, terrestrial heat flow, thermal conductivity.

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Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan,Northwest china:Evidence from sandstone detrital and geochemical records

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Science china Earth Sciences 2005年第9期48卷 1387-1402页

作者： LI Zhong1. GUO Hong2. wang Daoxuan3.& LIN Wei1.1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 1.002., {1. 2. Tarim Oilfield Branch, CNPC, Korla 841.00, {1. 3. Hefei university of Industry, Tunxilu 1.3. Hefei 2.0009, {1. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing Chin Tarim Oilfield Branch CNPC Korla China Hefei university of Industry Hefei Chin

Similar to compositional evolution of sandstone modes and detrital heavy minerals from different profiles in the Kuqa Depression, Northwest china, major element analysis of whole sandstones from the same profiles shows four discontinuous depositional interfaces or periods, respectively corresponding to Lower Triassic\Middle Triassic, Upper Jurassic\Lower Cretaceous, Lower Cretaceous\Paleogene and Miocene\Pliocene, and indicates five-phase evolution during Mesozoic-Cenozoic: (1. From the first to fifth phase, a depositional suite changes from maroon and coarse clastic, through grey-dark grey and fine, red and coarse, red-mottled, interlayered by gypsum, to brown and coarse clastic assemblages, accompanying detrital component evolution in unstable-stable-unstable-very unstable-very unstable assem- blages. It is indicated that carbonate and complex detritus gradually dominate in sandstones in post-Late Jurassic, with rapid reduction of compositional maturity. (2. For major element geo- chemical parameters of whole sandstones, CaO and Fe2.O * 3.MgO contents show a change sequence in high-low-high-higher-highest values, with rapid increasing in post-Late Jurassic. (3. Contra some aggregative indicators for weathering indexes of sandstone detrital component, Al2.3.(CaO+Na2.) and ln(Q/(L+CE)), show a change sequence in low-high-low-lower-lowest ratios, with rapid decreasing in post-Late Jurassic. It is found that sandstone samples of the first, second and later three phases may be distinguished from the A-CN-K and A-CNK-FM diagrams respectively. Therefore, in the Kuqa Depression-Tianshan, the most important discontinuous depositional interface recording paleotectonic and paleoclimatic transition occurred in Early Triassic\Middle Triassic and Late Jurassic\Early Cretaceous, respectively, and, however, tec- tonic differentiations of basin-range system finally result in distinct depositional systems but similar detrital weathering indexes across the Lower Cretaceous\Paleogene

关键词： Tianshan, Kuqa Depression, basin-range, depositional record, tectonic transition, Mesozoic-Cenozoic.

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The role of aerial algae in the formation of the landscape of the Yunnan Stone Forest,Yunnan Province, china

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Science china Earth Sciences 2004年第9期47卷 846-864页

作者： TIAN Youping1.3. ZHANG Jie2. SONG Linhua1.& BAO Haosheng2.1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 1.01.1. china 2. Department of Geography, {1. university, nanjing 2.0093. china 3. School of Earth Sciences and Resources, china university of Geosciences, Beijing 1.0083. china Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China School of Earth Sciences and Resources China University of Geosciences Beijing China Department of Geography Nanjing University Nanjing China

Aerial algae on the surface of carbonate rocks at the Stone Forest, Shilin County, Yunnan Province, china, and their bioerosion were investigated in the field and studied in the laboratory in detail. Through the observation, identification and statistics of more than one hun- dred algal samples and rock samples with the optical microscopes (stereomicroscope, biological microscope) and the scanning electronic microscope (SEM), the relationships between erosional forms on the surface of the Stone Forest and algae and/or algal communities and the genetic mechanism for the formation of erosional forms were analyzed. It is suggested that aerial algae play an active role in bioerosive processes that may affect the formation of karst erosional forms. These effects include both direct and indirect ones. The direct effect is the initiative control (algal shape-controlling role) of algae on the formation of karst forms of various scales, mostly mi- cro-scale (1.-3.) and minor-scale (1.-3.1.-1.) erosional forms. The algal shape-controlling roles can be divided into the algal individual shape-controlling role and the algal community shape-controlling role. The former mostly controls the formation of micro-scale erosional forms, while the latter mostly controls the formation of micro-scale and smaller minor-scale erosional forms. The indirect effect refers to the promoting role of algae in the formation of karst forms, which may affect the formation of karst forms of all types and scales. The bioerosion of algae accelerates the weathering process of the whole Stone Forest karst landforms.

关键词： aerial algae, bioerosion, the Stone Forest, Yunnan Province, china.

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Discovery of sponge body fossils from the late Meishucunian (Cambrian) at Jinsha, Guizhou, south china

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Progress in Natural Science:Materials International 2005年第8期15卷 708-712页

作者： YANG Xinglian 1.2., ZHAO Yuanlong2. {3. Yue2.and {3. Pingli2.1. nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, nanjing 2.0}008, china 2. Institute of Resource and Environment, Guizhou {13., Guiyang 550003. china) nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China. Institute of Resource and Environment Guizhou University Guiyang 550003 China

Here we report discovery of a sponge body fossil Triticispongia sp. from the base of lower Cambrian Niutitang Formation at Jinsha, Guizhou. Stratigraphically, the fossil horizon is located below Ni-Mo ore layer with the Niutitang Biota above, and is equivalent to the late Meishucunian. The species is global in shape with skeletons composed of stauractins and monaxons. Triticispongia sp. reported here may be the earliest sponge body fossils of Cambrian, which provides new information for understanding early evolution and radiation of sponge animals.

关键词： sponges Cambrian Niutitang Formation Guizhou china.

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Lithology, kinematics and geochronology related to Late Mesozoic basin-mountain evolution in the Nanxiong-Zhuguang area, South china

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Science china Earth Sciences 2004年第8期47卷 673-688页

作者： SHU Liangshu1. DENG Ping1.2. {2. Bin1. TAN Zhengzhong2. YU Xinqi1.& SUN Yan1.1. Department of Earth Sciences, {1. university, nanjing 2.0093. china 2. Research Institute No.2.0, CNNC, Shaoguan 51.02., china Department of Earth Sciences Nanjing University Nanjing China Research Institute No.2.0 CNNC Shaoguan China

The Nanxiong red-bed basin and its adjacent Zhuguang granite form a distinctive basin-mountain landform in the Nanling region, South china. Research results suggest that the Zhuguang granite is a polyphase composite pluton developed on the metamorphic basement of the paleo-Tethys-paleo-Asian tectonic regime and possesses geometrical and kinematic features of hot-doming extensional tectonics at the middle-upper crustal level, which is considered as a magmatic complex that resulted from the collision-orogeny during the Indosinian Period, the subduction-consuming during the Early Yanshanian Period and the intra-continental basaltic underplating and deep-seated geodynamics during the Late Yanshanian Period. The Nanxiong basin is a Late Cretaceous-Paleogene asymmetric faulted basin that is characterized by a fault boundary on the northern side and an uncomformable boundary on the southern side, its deposit center was migrated gradually from south to north. Structural kinematic results on the basin-mountain coupled zone demonstrate that the ductile and the brittle rheological layers show a quite coincident sense of shear, implying that it is a continuous process from the ductile extensional deformation followed by locally sinistral strike-slip shear at a middle-crustal level to the brittle tensional deformation at a upper-crustal level during formation of granitic doming extensional tectonics. The Zhuguang granite and the Nanxiong faulted basin constructed a semi-graben tectonic system. Lithological and geochemical results suggest that the Late Triassic to Jurassic granitic bodies in the Zhuguang have some similar features: high SiO2. Al2.3. K2. contents, alkalinity index > 2.8, ANKC value > 1.1. LREE-enriched pattern with high REE contents, marked negative Eu anomalies, enrichment in Rb and Th, depletion in Ba and Nb, showing a K-rich and Al-rich calc-alkaline affinity, which suggest a continuous magmatic evolution from Late Triassic to Jurassic. Formation of Nanxiong ba

关键词： lithology,structural kinematics,basin-mountain evolution,SHRIMP age,Zhuguang granite,Nanxiong basin.

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