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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, tongji university, shanghai 200092, china china university of Geosciences Henan Polytechnic university South-Central university for Nationalities tongji university

Studies show positive shifts of inorganic and organic carbon isotope values (δ 13Ccarb and δ 13Ckerogen) from +0.4. (‰ V-PDB) to +3.54.(‰ V-PDB) and from ?29.38 (‰ 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.

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A multi-layer model for early diagenesis

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Chinese Science Bulletin 1997年第16期42卷 1385-1387页

作者： MEI HongmingDepartment of marine geology, tongji university, shanghai 200092,{4. Department of marine geology Tongji University Shanghai China

EARLY diagenesis is defined here as a series of physical, chemical and biological reactions operating between depositional particles, porewaters and environmental water medium in the processes of deposition and shallow burial. Early diagenesis can produce geochemical succession within deposits, which can be divided from top to bottom into oxidation zone (OX), sulphate reduction zone (SR) and methanogenesis zone (ME). Part of the reaction

关键词： early diagenesis biogeochemical zone multi-layer model.

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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, tongji 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

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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, tongji 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 23CO- 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

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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, shanghai 200092,{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

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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, shanghai, {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

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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 {4. geology, tongji university, shanghai 200092, china Faculty of Earth Science China University of Geosciences Wuhan China laboratory of marine geology Tongji University 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 33333a, 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.

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Cycladophora davisiana(Radiolarian)in the Bering Sea during the late Quaternary:A stratigraphic tool and proxy of the glacial Subarctic Pacific Intermediate Water

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Science china Earth Sciences 2005年第10期48卷 1698-1707页

作者： WANG Rujian1 & CHEN Ronghua2 1. State Key laboratory of marine geology, tongji university,{4., china 2. The Key laboratory of Submarine Geoscience, State Oceanic Administration, Hangzhou 310012, china tongji university State Oceanic Administration

Cycladophora davisiana (Radiolarian) contents are counted in two cores of the Ber-ing Sea and correlated well with the oxygen isotopic records of ice in the deep core obtained by the Greenland Ice Sheet Project II (GISP 2) and deep-sea sediments (SPECMAP) of the world oceans. Millennial scale climatic events, for example, Younge Dryas and B?lling/Aller?d events, Heinrich1 and Dansgaard-Oeschger1events, recorded by C. davisiana percents are distin-guished from Core B4.2. C. davisiana events b, c1, c2, d, e1 and e2, respectively, corresponding to oxygen isotopic 2.0, 3.1, 3.3, 4.0, 5.1 and 5.3, are identified from Core B2-9. High resolution re-cords of C. davisian are tuned to the oxygen isotopic records in GISP 2 and SPECMAP and the depth-age frameworks are established in the two cores, supplying a stratigraphic base for future paleoceanographic and paleoclimatic studies. High C. davisiana during the glacial periods in the two cores indicate that they can serve as a proxy of the glacial Subarctic Pacific Intermediate Water, which verifies the glacial Subarctic Pacific Intermediate Water brought from the Bering Sea.

关键词： Cycladophora davisiana, stratigraphic tool, YD and B/A events, Heinrich 1 and D/O1 events, proxy of glacial Subarctic Pacific Intermediate Water, late Quaternary, Bering Sea.

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Stage characteristics for the development of late Quaternary paleosols in the Yangtze Delta area

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Chinese Science Bulletin 1999年第9期44卷 857-860页

作者： CHEN Qingqiang and LI Congxianlaboratory of marine geology , tongji university ,{4., china Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 51064., china laboratory of marine geology Tongji University Shanghai China Guangzhou Institue of Geochemistry Chinese Academy of Sciences Guangzhou China

The late Quaternary paleosols in the Yangtze Delta area developed in the period of 25 000—12 000 aBP. Phytolith ratios (value A) of contents of fan, square and rectangle types indicaring the warm and humid climate to those of bar, hat and point types indicating cold and dry climates decrease upwards overall on profiles of the paleosols, suggesting that the climates turned from warm and humid to cold and dry. So, the paleosols developed mainly during the regression before the last glacial maximum. Changes of value A indicate no trend of warming, suggesting that the transgression was rapid after the last glacial maximum. The development of the paleosols exhibited obvious stages, which were controlled remarkably by transgression and regression: Ⅰ. Period of alternation of deposition and pedogenesis, which was from the occurrence of regresson before the last glacial maximum to the time when sea levels fell close to the lowest;Ⅱ. Exposure period with continual pedogenesis, which was terminated when the

关键词： paleosol phytolith development processes late Quaternary Yangtze Delta.

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Palynological record during the Pleistocene (between 1.05 Ma and 0.36 Ma) from ODP114., northern South china Sea

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Science china Earth Sciences 2004年第1期47卷 30-36页

作者： HUANG Fei & SUN XiangjunInstitute of geology and Paleontology, Chinese Academy of Sciences, Nanjing 210008, china Institute of Botany, Chinese Academy of Sciences, Beijing 100093, china Key laboratory of {4. geology, Ministry of Education, tongji university, shanghai 200092, china Correspondence should be addressed to Huang Fei Institute of geology/Paleontology Chinese Academy of Sciences Nanjing 210008 China Institute of Botany Chinese Academy of Sciences Beijing 100093 China Key laboratory of marine geology Ministry of Education Tongji University Shanghai 200092 China

This paper presents the pollen record from the lower section of ODP114. (depth 501.3-225.7 m, ca. 1.05-0.36 Ma). Two pollen zones (PA and PB) and eleven pollen subzones are recognized. Within zone PB, the 11 pollen subzones (PB21-11) are defined according to the pine, fern and herb variations, and are equivalent to the marine isotope stages 21-11 (MISs 21-11). The interglacial periods are typified by an increase in pine pollen and fern spores, and a decrease in herbaceous pollen, while the patterning during the glacial periods is just the opposite. During the interglacial periods, pollen assemblages were dominated by pine similar to those of the present day, suggesting that the paleoenvironment of the interglacial periods was similar to that of the present day, whereas the glacial periods are marked by an increase in herbaceous pollen, mainly Gramineae and Cyperaceae, indicating that grassland covered the exposed continental shelf when sea level declined. Increased Artemisia percentages and the highest pine influx during MIS12 may result from a stronger winter monsoon.

关键词： pollen record, Pleistocene, ODP114., northern South china Sea.

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