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^(40)Ar/^(39)Ar chronology and geochemistry of high-K volcanic rocks in the Mangkang basin, Tibet

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Science China Earth sciences 2005年第1期48卷 1-12页

作者： ZHANG Huihua, HE Huaiyu, WANG Jianghai & XIE Guanghong Guangzhou institute of geochemistry,{2., Guangzhou 510640, China institute of geology and geophysics,{2., Beijing 10002., China College of Life sciences, Sun Yat-Sen University, Guangzhou 5102.5, China 1. chinese academy of sciences Guangzhou Institute of Geochemistry 510640 Guangzhou China 2. chinese academy of sciences Institute of Geology and Geophysics 100029 Beijing China 3. College of Life sciences Sun Yat-Sen University 510275 Guangzhou China

Our two newly obtained high-quality 40Ar/39Ar ages suggest that the high-K volcanic rocks of the Lawuxiang Formation in the Mangkang basin, Tibet were formed at 33.5 ( 0.2.Ma. The tracing of elemental and Pb-Sr-Nd isotopic geochemistry indicates that they were derived from an EM2.enriched mantle in continental subduction caused by transpression. Their evidently negative anomalies in HFSEs such as Nb and Ta make clear that there is an input of continental material into the mantle source. The high-K rocks at 33.5 ( 0.2.Ma in the Mangkang basin may temporally, spatially and compositionally compare with the early one of two-pulse high-K rocks in eastern Tibet distinguished by Wang J. H. Et al., implying that they were formed in the same tectonic setting.

关键词： Cenozoic high-K volcanic rocks, 40Ar/39Ar chronology, Mangkang basin, Tibet.

An unusual isotopic fractionation of boron in synthetic calcium carbonate precipitated from seawater and saline water

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Science China Chemistry 2006年第5期49卷 454-465页

作者： XIAO Yingkai1,2.LI Shizhen1,WEI Haizhen1,SUN Aide1,ZHOU Weijian2.& LIU Weiguo2.1. Qinghai institute of Salt Lakes,chinese {2. of sciences,Xining 810008,China 2. State key laboratory of Loess and Quaternary geology,institute of Earth Environment,chinese {2. of sciences,Xi’an 710075,China 1. Qinghai institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China 2. State key laboratory of Loess and Quaternary {2. Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

Inorganic calcium carbonate precipitation from natural seawater and salinewater at various pH values was carried out experimentally. The results show the clear positiverelationships between boron concentration and δ^(11)B of inorganic calcium carbonate with the pH ofnatural seawater and saline water. However, the variations of boron isotopic fractionation betweeninorganic calcite and seawater/saline water with pH are inconsistent with the hypothesis thatB(OH)_4^- is the dominant species incorporated into the biogenic calcite structure. The isotopicfractionation factors a between synthetic calcium carbonate precipitate and parent solutionsincrease systematically as pH increases, from 0.9884 at pH 7.60 to 1.0072.at pH 8.60 for seawaterand from 0.982. at pH 7.60 to 1.0178 at pH 8.75 for saline water. An unusual boron isotopicfractionation factor of larger than 1 in synthetic calcium carbonate precipitated fromseawater/saline water at higher pH is observed, which implies that a substantial amount of theisotopically heavier B(OH)_3 species must be incorporated preferentially into synthetic inorganiccarbonate. The results propose that the incorporation of B(OH)_3 is attributed to the formation ofMg(OH)_2.at higher pH of calcifying microenvironment during the synthetic calcium carbonateprecipitation. The preliminary experiment of Mg(OH)_2.precipitated from artificial seawater showsthat heavier ^(11)B is enriched in Mg(OH)_2.precipitation, which suggests that isotopically heavierB(OH)_3 species incorporated preferentially into Mg(OH)_2.precipitation. This result cannot beapplied to explain the boron isotopic fractionation of marine bio-carbonate because of thepossibility that the unusual environment in this study appears in formation of marine bio-carbonateis infinitesimal. We, however, must pay more attention to this phenomenon observed in this study,which accidentally appears in especially natural environment.

关键词： boron, isotopic fractionation, calcium carbonate precipitate, seawater, saline water.

Low-temperature magnetic properties of horse spleen ferritin

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chinese Science Bulletin 2010年第27期55卷 3174-3180页

作者： TIAN LanXiang 1,2.CAO ChangQian 1,2.LIU QingSong 1,2.&PAN YongXin 1,2.1key laboratory of the Earth’s Deep Interior,{2. of {2. and geophysics,chinese academy of sciences,Beijing 10002.,China 2.ranco-chinese Biomineralization and Nano-structures laboratory,Beijing 10002.,China key laboratory of the Earth''s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Franco-chinese Biomineralization and Nano-structures laboratory Beijing 100029 China

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Wohlfarth-Cisowski test for the investigated sample at 5 K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of Tb≈12.K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Néel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy Ea=(5.52.0.16)×10-2. J;the effective magnetic anisotropy energy constant Keff=(4.65±0.14)×10 4 J/m3 and the pre-exponential frequency factor f0 =(4.52.2.93)×1011 *** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词：马脾铁蛋白低温度磁性质透射电子显微镜磁各向异性常数纳米粒子生物医学技术交流磁化率

Carbon and Oxygen Stable Isotope Values and Microfossils at 41.4-4.5ka BP in Tai Co,Tibet,China,and Their Paleoclimatic Significance

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1036-1050+1052-1056+1051页

作者： ZHENG Mianping~(1,2.*),LIU Junying~(1,3),MA Zhibang~(1,4),WANG Hailei~(1,2. and MA Nina~(1,2. 1 MLR key laboratory of Saline Lake Resources and Environment,{2. of Mineral Resources,CAGS, Beijing 100037,China 2.Research and Development Center for Saline Lakes and Epithermal Deposits,{2. academy of Geological sciences,Beijing 100037,China 3 {2. of geology,{2. academy of Geological sciences,Beijing 100037,China 4 key laboratory of Cenozoic geology and Environment,{2. academy of sciences,Beijing 10002., China MLR key laboratory of Saline Lake Resources and Environment Institute of Mineral Resources CAGS Beijing 100037 China Research and Development Center for Saline Lakes and Epithermal Deposits Chinese Academy of Geological Sciences Beijing 100037 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China key laboratory of Cenozoic {2. and Environment Chinese Academy of Sciences Beijing 100029 China *Correspondence: Mianping ZHENG *Correspondence: Corresponding author. E-mail: zhengmp2010@***

Two sedimentary sections were measured at Tai Co(Co means lake in Tibetan) in western Tibet,*** two sections are almost all composed of clay carbonate beds except in their lower parts where there are carbonized plants at>10 cm depths and dark-colored carbonate clay and clay at 50-70 cm depths,yielding abundant gastropods,ostracods,and *** carbon and oxygen stable isotope values of carbonate,ostracods,and charophytes and ecological features of microfossil communities indicate the following climatic change in the area from 41.4 to 4.5 ka BP:at 41.4-2..2.ka BP,the climate was relatively wet;at 2..2.2..5 ka BP,it was slightly warm-dry;at 2..5-2..5 ka BP,it was warm-wet;at 2..5-2..0 ka BP,it was slightly cold-wet;at 2..5-17.5 ka BP,it became cold abruptly and slightly wet,implying the climate of the last glacial maximum;at 17.5-16.0 ka BP,it was slightly cold-dry;at 16.0-11.8 ka BP,it was slightly warm-wet;at 11.8-10.4 ka BP,it was relatively cold-dry, roughly equivalent to the climate of the Younger Dryas,and at 10.4 ka BP,the temperatures began to rise again;at 10.4-9.4 ka BP,it was slightly warm-wet;at 9.4-8.5 ka BP,there occurred short warm-wet oscillations;at 8.5-7.9 ka BP,it was slightly dry-cold,representing a strong temperature-lowering and drying event in the postglacial stage;at 7.8-6.3 ka BP,it was slightly warm-wet;at 6.3-4.5 ka BP,the climate tended to be cold-dry.4.5 ka BP recorded the maximum aridity since the late part of the late Pleistocene.

关键词： sedimentary environment index paleoclimatic changes late Pleistocene-Holocene(41.4-4.5 ka BP) Tai Co Tibet

Chronological record of the Early Mesozoic underplating in the northern margin of North China—U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

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Progress in Natural Science:Materials International 2007年第8期17卷 943-947页

作者： Shao ji'an~(1,2.*) Zhang Hongfu~2.Liu Xiaoming~3 Li Zhitong~4 (1.School of Earth and Space sciences,Peking University,Beijing 100871,China 2.institute of {2. and geophysics and key laboratory of Mineral Resources,chinese academy of sciences,Beijing 10002.,China 3.key laboratory of Continental Dynamics,Northwestern University,Xi'an 710069,China 4.institute of {2. and Mineral Resources of Shenyang,Shenyang 110032.China) [a]School of Earth and Space sciences Peking University Beijing China [b]laboratory of Mineral Resources Chinese Academy of Sciences Institute of Geology and Continental Dynamics Beijing China [c]key laboratory of Continental Dynamics Northwestern university Xi'an China [d]institute of geology and Mineral Resources of Shenyang Shenyang China

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Forma- tion in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-MS chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 2.4 Ma,which is consistent with the age of the Early Mesozoic underplating granulites,and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma,which is highly consistent with the Ar-Ar dating of the host volcanic *** of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites,indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.

关键词： northern margin of North China Mesozoic volcanic rock U-Pb chronometry of zircon underplating granulite

Sporopollen analysis of Core B10 in the southern Yellow Sea and the reflected characteristics of climate changes

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chinese Science Bulletin 2003年第B06期48卷 42-48页

作者： FU Mingzuo~(1,2.3), LI Zhen~1, XU Xiaowei~1 & SHl Xuefa~1 1. key laboratory of Marine Sedimentology and Environmental {2., First {2. of Oceanography. State Oceanic Administration, Qingdao 2.6061. China 2. {2. of Oceanology, chinese academy of sciences, Qingdao 2.6071. China 3. Graduate School, chinese academy of sciences, Beijing 100039. China 1. key laboratory of Marine Sedimentology and Environmental {2. First institute of Oceanography State Oceanic Administration 266061 Qingdao China 2. institute of Oceanology Chinese Academy of Sciences 266071 Qingdao China 3. Graduate School Chinese Academy of Sciences 100039 Beijing China

Eight sporopollen zones have been divided based on the results of high-resolution sporopollen analysis of Core B10 in the southern Yellow Sea. Based on the results along with ^14C datings and the subbottom profiling data,climatic and environmental changes since the last stage of late Pleistocene are discussed. The main conclusions are drawn as follows: (1) the vegetation evolved in the process of coniferous forest-grassland containing broad-leaved trees→coniferous and broad-leaved mixed forest→coniferons and broad-leaved mixed forest-grassland prevailed by coniferous trees→coniferous and broad-leaved mixed forest-grassland containing evergreen broad-leaved trees→coniferons and broad-leaved mixed forest-grassland prevailed by broadleaved trees→deciduous broad-leaved forest-meadow containing evergreen broad-leaved trees→coniferous and broadleaved mixed forest-grassland prevailed by broad-leaved trees→coniferous and broad-leaved mixed forest containing evergreen broad-leaved trees; (2. eight stages of climate changes are identified as the cold and dry stage, the temperate and wet stage, the cold and dry stage, the warm and dry stage, the temperate and wet stage, the hot and dry stage, the temperate and dry stage, then the warm and dry stage in turn; (3) the sedimentary environment developed from land,to littoral zone, to land again, then to shore-neritic zone; and (4) the Yellow Sea Warm Current formed during early-Holocene rather than Atlantic stage.

关键词：中国黄海气候变化碳14年代测定底基压型数据更新世沉积环境大西洋

SHRIMP zircon U-Pb age and Nd isotopic study on the Nyainqêntanglha Group in Tibet

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Science China Earth sciences 2005年第9期48卷 1377-1386页

作者： HU Daogong1, WU Zhenhan1, JIANG Wan1, SHI Yuruo2. YE Peisheng1 & LIU Qisheng1 1. institute of Geomechanics, chinese {2. of Geological sciences, Beijing 100081, China 2. institute of geology, chinese {2. of Geological sciences, Beijing SHRIMP Centre, Beijing 100037, China 1. institute of Geomechanics Chinese Academy of Geological Sciences 100081 Beijing China 2. institute of geology Chinese Academy of Geological Sciences Beijing SHRIMP Centre 100037 Beijing China

The Nyainqêntanglha Group is traditionally viewed as the oldest metamorphic basement in the Lhasa block, but its formation age and tectonic setting remain debate. Zircons extracted from the metamorphic sequence of volcanics and intrusions of the Nyainqêntanglha Group, 10 km west of Nam Co in northern Lhasa block, have been investigated by cathodolu- minescence (CL), backscattered (BSE) and dated by ion microprobe (SHRIMP). We conclude that the U-Pb age of 787±9 Ma of zircons from the trondhjemite imposes a constraint on maxi- mum protolith age, and minimum formation age of the Nyainqêntanglha Group is constrained by U-Pb age of 748±8 Ma of zircons from the granite. The formation age of the Nyainqêntanglha Group is consistent with sedimentary age of Greater Himalayan rocks, showing that they devel- oped coevally in an arc-basin tectonic setting of Neoproterozoic active continental margin along the northern margin of the India shield. The inherited zircons from the tholetiite and granite give older 2.7Pb/2.6Pb ages from 947 to 1766 Ma. The positive εNd( t ) value indicates that the mafic rocks were derived from the depleted mantle, but contaminated by the older continental crustal material. Integrated Nd model age and U-Pb age data provide excellent evidence for the exis- tence of Mesoproterozoic basement in the Lhasa block during Neoproterozoic time.

关键词： Nyainqêntanglha Group, SHRIMP dating, Nd isotope, Neoproterozoic, Tibet.

Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central chinese Loess Plateau

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chinese Science Bulletin 2007年第17期52卷 2407-2412页

作者： DU XueQing1,6, WANG YongHong2. REN JianGuo3, YE XianRen4 & LU HuaYu5,1 1 State key laboratory of Loess and Quaternary {2., {2. of Earth Environment, chinese academy of sciences, Xi’an 710075, China 2.College of Marine Geosciences, Ocean University of China, Qingdao 2.6003, China 3 National Natural Science Foundation of China, Beijing 100085, China 4 lanzhou Research Center for Petroleum and Natural gas Resources, institute of geology and geophysics, chinese academy of sciences, lanzhou 73.000, China 5 key laboratory of Coast and Island Development, School of Geographic and Oceanographic sciences, Nanjing University, Nanjing 2.0093, China 6 Graduate University of chinese academy of sciences, Beijing 100049, China State key laboratory of Loess and Quaternary {2. Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planetary dust particles (IDPs), which are very rich in 3He, continuously bombard the Earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the Earth surface sediments. Since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concen- tration and helium isotopic ratio. Results show that the 3He/4He ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4He ratio of the extracted magnetic substances is also higher than that of the average level of the Earth’s crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

关键词：中国黄土高原古土壤氦同位素行星际尘埃颗粒反方向磁化

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 {2., Tongji University, Shanghai 2.0092. China 2. The key laboratory of Submarine Geoscience, State Oceanic Administration, Hangzhou 310012. China State key laboratory of Marine {2. Tongji University Shanghai China The key laboratory of Submarine Geoscience State Oceanic Administration Hangzhou China

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.