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Quaternary high-resolution opal record and its paleoproductivity implication at ODP Site 114.,southern South china Sea

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Chinese Science Bulletin 2003年第4期48卷 363-367页

作者： WANG Rujian & LI Jian laboratory of marine geology, MEO, {3. University,{4., china laboratory of marine geology MEO Tongji University Shanghai 200092 China

The correlation of opal content and MAR with oxygen isotopic records of benthonic foraminifera at Site 114., southern South china Sea indicates that, since about 900 ka, the increasing opal content and MAR during the interglacial periods is inferred to reflect the higher surface productivity, for the intensified summer monsoon during the interglacial periods would result in the enhanced upwelling and nutrient supply. Time-sequence spectral analyses of oxygen isotopic record, opal content and MAR at intervals of 0900 ka reveal that the changes of surface productivity were dominantly forced by the variations of the earth orbital cycles.

关键词：中国南海第四纪蛋白石含量 MAR 古生产力四膜虫沉积物氧同位素

Calcium carbonate pump during Quaternary glacial cycles in the South china Sea

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Chinese Science Bulletin 2003年第17期48卷 1862-1869页

作者： LIU Zhifei, XU Jian, TIAN Jun & WANG Pinxian laboratory of marine geology, {3. University,{4., china laboratory of marine geology Tongji University

The preservation and dissolution of calcium carbonate (namely calcium carbonate pump) controls the pH of seawater in global oceans by its buffer effect, and in turn plays a significant role in global changes in atmospheric CO2 concentration. The results from measured carbonate con-tents over the past 2 Ma at ODP Site 114. in the South china Sea provide high-resolution records to explore the process of the calcium carbonate pump during Quaternary glacial cy-cles. The results indicate statistically that the highest car-bonate accumulation rate leads the lightest d 18O by about 3.6 ka at transitions from glacials to interglacials, and that the strongest carbonate dissolution lags the lightest d 18O by about 5.6 ka at transitions from interglacials to glacials. The calcium carbonate pump releases CO2 to the atmosphere at the glacial-interglacial transitions, but transports atmos-pheric CO2 to deep sea at the interglacial-glacial transitions. The adjustable function of the calcium carbonate pump for the deep-sea 23.O- concentration directly controls parts of global changes in atmospheric CO2, and contributes the global carbon cycle system during the Quaternary.

关键词：中国南海碳酸钙第四纪冰川旋回海洋钻探图古气候

Relationships between bacterial-algal proliferating and mass extinction in the Late Devonian Frasnian-Famennian transition:Enlightening from carbon isotopes and molecular fossils

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Science china Earth Sciences 2005年第10期48卷 1656-1665页

作者： GONG Yiming1,2, XU Ran1, TANG Zhongdao1, SI Yuanlan3.& LI Baohua4.1. Faculty of Earth Science and State Key laboratory of Geological Processes and Mineral Resources, china University of Geosciences, Wuhan 4.0074. china 2. Institute of Resources & Environments, Henan Polytechnic University, Jiaozuo 4.4.03. china 3. Department of Computer Science, South-Central University for Nationalities, Wuhan 4.0074. china 4. laboratory of marine geology, {13. University, shanghai 200092, china Faculty of Earth Science and State Key laboratory of Geological Processes and Mineral Resources china University of Geosciences Wuhan china Institute of Resources & Environments Henan Polytechnic University Jiaozuo china Department of Computer Science South-Central University for Nationalities Wuhan china laboratory of marine geology {3. University {4. china

Studies show positive shifts of inorganic and organic carbon isotope values (δ 13.carb and δ 13.kerogen) from +0.4. (‰ V-PDB) to +3.54.(‰ V-PDB) and from ?29.3. (‰ V-PDB) to ?24.14.(‰ V-PDB), respectively, B* (Ba* = Ba/ (Al2O3.X 15%)) values from 0.015 to 0.14., TOC values from 0.02% to 0.21%, V/Cr values from 0.3.to 2.0, Sr/Ba values from 3.20 to 4..50 in the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone of the Yangdi sec-tion deposited in carbonate slope facies of Guilin, Guangxi, South china, which indicates that biomass, productivity, organic carbon burial and salinity increase and that oxygenation near the boundary between sediments and waters decreases from the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone. Abundance of molecular fossils increases and normal alkanes, isoprenoid hydrocarbon, terpanes and steranes are dominated from the Late Devonian Frasnian to the bottom of Famennian, which shows that the predecessors of molecular fossils of the Frasnian-Famennian (F-F) transition are dominated by marine phytoplankton, zooplankton and benthic bacteria with no photosynthesis. Therefore, it is considered that the F-F transitional mass extinction with a multistage, selection and global synchronizing was caused by bacte-rial-algal proliferating, continuing deterioration of the shallow marine ecoenvironment of the mid-dle-lower latitudes. A simple cause and effect chain can be expressed as: appearance of seed plants and multi-storied forests → enhanced chemical and biochemical weathering and pe-dogenesis → wide development of soils → increasing riverine nutrient fluxes in epicontinental sea → from superoligotrophic to eutrophic in epicontinental sea → proliferating of marine phyto-plankton and zooplankton → frequent red tide and anoxia → mass extinction of shallow marine organisms in the middle-lower latitudes. It is worth notice that the factor drawdown of atmos-pheric Pco2, climatic cooling and sea level falling c

关键词： mass extinction, bacteria-algae, carbon isotopes, molecular fossils, biodiversity, Late Devonian, Guangxi, South china.

Postglacial sea-level changes and development stages of fluvial-estuarine system

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Acta Oceanologica Sinica 1993年第4期12卷 573-584页

作者： Li Congxian Department of marine geology and Geophysics, tongji University,{3.,{4. Dept. of marine geology & Geophysics Tongji Univ. Shanghai 200092 China

-On the basis of the data obtained from the investigations on some rivers in china and Australia, the author discusses the spatial and temporal changes of various portions of fluvial-estuarine system during postglacial sea-level rising in present coastal and deltaic areas. The evolution of a fluvial-estuarine system can be divided into four development stages: early transgression, late transgression, stationary and regression. Early transgression brought about filling-in of the paleo-valley formed in low stand of sea level. In response to late transgression the estuaries were created, during the stationary stage the big swamp was developed. The regression led to estuaries to be filled with sediments and then became deltas. At the same locality the fluvial-estuarine system changed with time. In the transgressive period the lower reach of a river changed into an estuary, and then became nearshore area. In the regressive period the nearshore area changed into an estuary , and then became delta.

关键词： Sea-level fluvial-estuarine system postglacial period paleo-valley paleo-interfluve retrogressive aggrada-tion

Paleobiogeography of Ostracoda and Foraminifera in the china sea area

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Acta Oceanologica Sinica 1991年第1期10卷 93-105页

作者： Wang Pinxian and Zhao Quanhong Department of marine geology, tongji University, {3., {4., china Dept marine geology Tongji Univ Shanghai 200092 China China

The distribution of ostracods and benthonic foraminifers in the china sea area is briefly reviewed from the paleobio-geographic viewpoint in this paper. Three regions can be distinguished in the area on the basis of modern distribution data: Region I (the Huanghai Sea and the Bohai Sea) with cool and temperate forms, Region I (the East china Sea and the northern part of the South china Sea) with subtropical warm-water forms and Region Ⅲ (central and southern parts of the South china Sea) with larger foraminifers and other tropical warm-water forms. The occurrence of Nummulites-Discocyclira fauna in the Eocene deposits of the East china Sea indicates a northward extension of tropical zoogeographical region at the time, whereas the distribution pattern of the Miocene Nephrolepidina-Miogypsiua-Austrotrillina fauna in the South china Sea resembles that of the present larger-foraminiferal fauna. In the South china Sea and Taiwan, a warm-water fauna with Asterorotalia and Pseudorotalia first appeared in late Miocene and then flourished in the Pliocene. Its northward invasion into the Bohai Sea area during late Pleistocene may be related to changes in current system. Many of the endemic foraminiferal and ostracod genera and species ( Sinocytheridea etc. ) in recent coastal faunas probably have originated from the South china Sea, and their occurrence in Japan or Australia may be indicative of ties between these areas during glacial times.

关键词： Paleobiogeography of Ostracoda and Foraminifera in the china sea area

The Upper Devonian orbital cyclostratigraphy and numerical dating conodont zones from Guangxi,South china

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Science china Earth Sciences 2005年第1期48卷 32-41页

作者： GONG Yiming, XU Ran, TANG Zhongdao & LI Baohua Faculty of Earth Science, china University of Geosciences, Wuhan 4.0074. china laboratory of marine {4., tongji University, shanghai 200092, china 1. Faculty of Earth Science China University of Geosciences 430074 Wuhan China 2. laboratory of marine geology Tongji University 200092 Shanghai China

The hierarchically organized laminae, bundles, bundlesets and superbundlesets which correspond to a sub-Milankovitch, obliquity or precession, eccentricity and long eccentricity cyclothems, respectively, have been distinguished from the Upper Devonian Fras-nian-Famennian (F-F) transitional carbonate successions deposited in the carbonate-basin and slope facies of Guangxi, South china. The durations of cyclothems are 8000-10000a, 16667a or 3.3.3., 100000a and 4.0000a, respectively. The ratio of eccentricity to precession, eccentricity to obliquity, and long eccentricity to eccentricity is 1 : 6, 1 : 3.and 1 : 4.in the Devonian, respectively. Orbital cyclostratigraphical studies show that the durations of the conodont falsio-valis Zone, transitans Zone, punctate Zone, Lower hassi Zone, Upper hassi Zone, jamieae Zone, Lower rhenana Zone, Upper rhenana Zone, linguiformis Zone, Lower triangularis Zone, Middle triangularis Zone and Upper triangularis Zone are 0.4. 0.4. 0.4. 0.3. 0.4. 0.2, 0.8, 0.6, 0.8, 0.3. 0.3.and 0.3.Ma from bottom to top, respectively, and the duration of the Frasnian is 4.3.Ma. The conodont is the normal marine organism of the latest mass extinction (the latest linguiformis Zone) and the first recovery (including the whole Lower triangularis and Middle triangularis Zone) in the F-F transition. The conodont mass extinction and recovery lasted 200000-100000a and 0.6 Ma, respectively. We consider that average durations of the fossil zones calculated by reported numerical ages divided by fossil zone numbers within a stage or series or system cannot discovery complications and non-uniformity of evolutionary organisms and environments.

关键词： orbital cyclostratigraphy, conodont zone, numerical dating, mass extinction, Devonian, Guangxi, South china.

Determination of tectonic background for sedimentary basin from sandstone geochemistry

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Chinese Science Bulletin 1998年第14期43卷 1191-1196页

作者： SHAO Lei 1, K. Stattegger 2 and LI Wenhou 3.1. laboratory of marine geology, {3. University,{4., china 2. Geological and Paleontological Institute, University of Kiel, 24.18 Kiel, Germany 3. Department of geology, Northwest Unive laboratory of marine geology Tongji University Shanghai China Geological and Paleontological Institute University of Kiel Kiel Germany Department of geology Northwest University Xi’an China

The chemical composition of sedimentary rocks is mainly controlled by source rocks. Through examining chemical composition of terrigenous rocks, the tectonic evolution of a sedimentary basin can be modeled. The Turpan Basin belongs to a continental sedimentary basin and its source rocks are derived from the upper continental crust.

关键词： sedimentary rock geochemistry basin analysis Turpan Basin.

Mesozoic subduction-accretion zone in northeastern South china Sea inferred from geophysical interpretations

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Science china Earth Sciences 2006年第5期49卷 471-482页

作者： ZHOU Di1, WANG Wanyin2, WANG Jialin3. PANG Xiong4. CAI Dongsheng5 & SUN Zhen1 1. Key laboratory of Marginal Sea geology, South{3. Sea Institute of Oceanology, Chinese Academy of Sciences, Guang- zhou 5103.1,{3. 2. College of Geological and Topographical Engineering, Chang’an University, Xi’an 710054.{3. 3. Key laboratory of marine geology, tongji University, shanghai 200092,{3. 4.{3. National Offshore Oil Co. Limited – Shenzhen Branch, Shenzhen 518067,{3. 5.{3. National Offshore Oil Co. Limited – Research Center, Beijing 100027,{3. 1. Key laboratory of Marginal Sea geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China 2. College of Geological and Topographical Engineering Chang’an University Xi’an 710054 China 3. Key laboratory of marine geology Tongji University Shanghai 200092 China 4. china National Offshore Oil Co. Limited — Shenzhen Branch Shenzhen 518067 China 5. china National Offshore Oil Co. Limited — Research Center Beijing 100027 China

A segment of Mesozoic subduction-accretion zone was inferred across thenortheastern South china Sea at approximately NE4.0 orientation. Basic evidence includes thefollowing: A belt of peek gross horizontal Bouguer gravity gradient (PGHGBA) is comparable in sizeand intensity to that of the Manila subduction-accretion zone. A belt of high positive magneticanomalies appears to the north and sub-parallel to the PGHGBA, representing the volcanic arcassociated to the subduction zone. The PGHGBA crosses obliquely both Cenozoic structures and presentseafloor topography, indicating a pre-Cenozoic age. The segment is offset left-laterally byNW-running strike-slip faults, in concord with the Mesozoic stress field of South china. Inaddition, the existence of the subduction zone is supported by wide-angle seismic data obtained indifferent years by different institutions. At approximate localities, a north-dipping ramp of Mohosurface is indicated by records of ocean-bottom seismometers, and a strong reflector about 8 kmbeneath the Moho reflector is indicated by both OBS and long-cable seismic records. Theidentification of a segment of Mesozoic subduction zone in NE South china Sea fills nicely the gapof the Great Late Mesozoic Circum SE Asia Subduction-acrretion Zone, which extended from Sumatra,Java, SE Kalimantan to N Palawan, and from Taiwan, Ryukyu to SW Japan.

关键词： Mesozoic, subduction zone, SE Asia, NE South china Sea, geophysics.

Relationship between magnetic fabric parameters and dynamic characteristics of deposits in different environments

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Chinese Science Bulletin 1998年第22期43卷 1917-1921页

作者： CHEN Qingqiang 1,3., LI Congxian\+1 and CONG Youzi\+2 1. marine geology laboratory, {3. University,{4., china 2. First Institute of Oceanography, State Oceanic Administration of china, Qingdao 266003. china 3. Guangzhou Institute of marine geology laboratory Tongji University Shanghai China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China First Institute of Oceanography State Oceanic Administration of China Qingdao China

Comparison of magnetic fabric parameters of deposits in different modern sedimentary environments indicates that values of \%P, F\% and \%L\% of eolian deposits are lower obviously than those of hydrogenic ones respectively. On relationship diagrams of magnetic fabric parameters, data points of eolian samples concentrated in limited area near origin of coordinates indicate that dynamic intensity is lower with less variation; while those of hydrogenic ones depart from origin of coordinates suggest higher intensity of sedimentary dynamics. Analyses of dynamic characteristics of different sedimentary environments indicate that values of magnetic fabric parameters of deposits are determined by dynamic types and characteristics of depositional processes. Magnetic fabric analyses of deposits are effective in determination of sedimentary environments.

关键词： magnetic fabric parameters sedimentary environment transporting medium.