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FORMATION AND EUOLUTION OF TETHYS IN THE TIBETAN PLATEAU

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地学前缘 2000年第S1期7卷 334-335页

作者： Pan Yusheng[WT5,5”BX](institute of geology and {2., {3. Academy of Sciences, Beijing {4.,china)

The formation of the Tibetan Plateau is closely related to the evolution of Tethys. There have been many researchers and articles concerning the Tethys since *** proposed the concept in 1893. It means a large ocean which lies between Eurasia and Gondwanaland. With the development of Tethyan research, some new terms, appeared such as Neo\|Tethys, Paleo\|Tethys, and Proto\|Tethys, representing the Tethys in Mesozoic—Cenozoic, late Paleozoic and early Paleozoic respectively. The trace of an ocean from Sinian to Ordovician was discovered during the scientific expedition and Proto\|Tethys was proposed to name the ocean. Therefore, the Tibetan Plateau is the main scope of the Eastern Tethys. It can be divided c losely related into three zones which represent the main oceanic locations in th ree different *** Northern Tethyan Region lies in the Kunlun and Qilian Mountains, its remnant is the Fifth Suture Zone. It is also the northern boundary of the Tibetan Plateau The rift initiated after the continental basement had been formed in Sinian and gradually developed into an ocean, which was named Proto\|Tethys, the earliest Tethyan ocean known up to now. The petrochemical compositions of pillow lava in this zone show the characteristics of mid\|ocean ridge tholeiite basalt and the pelagic ophiolitic flysch were well developed, indicating a matured ocean. It was closed in Ordovician and Silurian.

关键词： formation and evolution Tethys Tibetan plateau suture zone structural deformation Gondwana land

Discovery of eclogite and its geological significance in Qiangtang area, central Tibet

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Science Bulletin 2006年第9期51卷 1095-1100页

作者： LI Cai1, ZHAI Qingguo2. DONG Yongsheng1 & HUANG Xiaopeng11. College of Earth Sciences, Jilin University, Changchun 13.061, china 2. {2. of geology, {3. Academy of Geological Sciences, Bei- jing 10003., china College of Earth Sciences Jilin University Changchun 130061 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China

Eclogite is first discovered from Qiang- tang area, central Tibet, which occurs as a lens in the high-pressure metamorphic belt comprising glauco- phane-muscovite schist and garnet-muscovite schist, along the south margin of Lungmu Co-Shuanghu Paleo-Tethys suture. A glaucophane 4.Ar/3.Ar age of 2.0 Ma and a phengite 4.Ar/3.Ar age of 2.1.9 Ma have been obtained from blueschists associated with eclogite. The rock consists of garnet, omphacite, amphibole, phengite, and rutile, etc, and the jadeite content in omphacite ranges from 3..7% to 3..95%. It is estimated that the temperature of the eclogite is 2.3. GPa. The discovery of Qiangtang ecologite fur- ther supports that there is a suture zone of Indo- chinese epoch in central Qiangtang area, and is very important for discssing the evolution of the pa- leo-ocean and paleo-plate tectonics in this area.

关键词： Qianghai-Tibet Plateau Qiangtang eclogite tectonics.

TAKE ANOTHER VISION TO THE UPLIFT OF THE QING—ZANG (TIBETAN) PLATEAU BASED ON CENOZOIC VOLCANISM

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地学前缘 2000年第S1期7卷 370-371页

作者： Liu Jiaqi [WT5,5”BX](institute of geology and {2.,{3. Academy of Sciences,Beijing {4., china)

The emergence of the Qing—Zang plateau is among the most important geological events on the globe since the Cenozoic Era. Many geological issues can find answer from here. The major issues concerning plateau probably have three: (1) geodynamics, timing and speed of the plateau uplift;(2. The plateau uplift impact on surrounding environment;(3. mineral resources in the plateau. The authors want to focuses on first issue based on volcanisms occurred in interior and surrounding of the plateau, The new opinions are following:(1) Each volcanic eruptive episode corresponded to strong uplift stage;(2. The dynamic mechanism of the plateau uplift can not ignore another force from west beyond collision between Indian and Eurasia plates from South;(3. The surrounding volcanic chain is not only related to the collision from South, but also from west.

关键词： Tibetan plateau the Cenozoic volcanism volcanic chain surro unding plateau west collision uplift mechanism

Planation Surfaces on the Tibet Plateau,china

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Journal of Mountain Science 2008年第4期5卷 310-317页

作者： ZHANG Xinbao HE Xiubin WANG Yangchun LONG Yi institute of Mountain Hazards and Environment CAS Chengdu 610041 China State Key Laboratory of Loess and Quaternary geology Institute of Earth Environment GAS Xi＇an 710075 China Graduate University of the chinese Academic of Sciences Beijing 100039 China

A planation hypothesis is proposed to explain landform evolution of the Tibet Plateau. A denudation threshold （T）, the maximum potential denudation rate for a certain type of rock, is introduced to explain the combined effects of lithology and tectonics on landform evolution. If the tectonic uplifting rate （U） is equal to or less than the threshold rate （U ≤ T）, the tectonic uplifting and terrain denudation are in dynamic equilibrium, and landforms are in a steady state. The end product should be planation surfaces whether the original landforms are flat plains or deeply dissected mountains. If U 〉 T, uplift and denudation are not able to reach a dynamic equilibrium state. The plateau surface is mostly underlain by soft rocks, such as the Mesozoic epimetamorphic argillites and Tertiary sedimentary rocks, while the mountain ranges comprise hard rocks, such as granite, gneiss and limestone. In soft rock regions, hills are low with a relative relief of mostly less than 100 m and the slopes are gentle at a gradient of 〈2.0. In contrast, hills can maintain steep slopes in hard rock regions. The Tibet Plateau has been under an equilibrium condition between tectonic uplifting and denudation except for the mountain ranges. The plateau might have reached the present altitudes before the Quaternary.

关键词： planation denudation threshold landform evolution Tibet Plateau china

Concentration Characteristics and Sources of Chemical Elements in Atmospheric Fine Particles (PM_(2.5)) in Autumn in Xi'an City

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Meteorological and Environmental Research 2011年第4期2卷 5-8页

作者： GAN Xiao-feng1,2. CAO Jun-ji2.3. WANG Qi-yuan4. SHEN Zhen-xing4. XU Hong-mei2.1. Department of Environmental Science and Technology, Xi’an Jiaotong University, Xi’an 71004.,{4. 2. State Key Laboratory of Loess and Quaternary {2., institute of Earth Environment, {3. Academy of Sciences, Xi’an 710075,{4. 3. institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 71004.,{4. 4. Department of Environmental Engineering, Xi’an Jiaotong University, Xi’an 71004.,{4.

[Objective] The aim was to study the concentration characteristics and sources of chemical elements in atmospheric fine particles (PM2.5) in autumn in Xi’an City. [Method] By means of mini-volume sampler, PM2.5 samples in atmosphere in Xi’an were collected in October 2.09, and the concentration characteristics and sources of elements in PM2.5 were analyzed. [Result] The average mass concentration of PM2.5 in atmosphere in autumn in Xi’an City was 168.4. μg/m3.which was higher than that of Beijing and Pearl River Delta area, and the minimum and maximum value were 53.2. and 3.8.16 μg/m3. respectively. The mass concentration of S, Zn, K, Cl, Ca and Fe in PM2.5 was above 1.0 μg/m3. being at high pollution level. In addition, K had obvious correlation with organic carbon (OC) and element carbon (EC), with the correlation coefficients of 0.76 and 0.75 (P2.5 in autumn in Xi’an. [Conclusion] The study could provide theoretical foundation for the control of urban environmental pollution.

关键词： Atmospheric fine particles Chemical element Enrichment factor Factor analysis china

Denitrification in Qi'ao Island coastal zone,the Zhujiang Estuary in china

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Acta Oceanologica Sinica 2009年第1期28卷 37-46页

作者： WANG Hu ZHOU Huaiyang PENG Xiaotong YANG Qunhui QIN Chaomei YIN Xijie CHEN Guangqian Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China State Key Laboratory. of Marine geology Tongji University Shanghai 200092 China Graduate University of chinese Academy of Sciences Beijing 100049 China

Samples of sediments and the overlying water were collected in the Qi＇ao Island coastal zone,the Zhujiang（Pearl River） Estuary（ZE）.Denitrification rates,sediment oxygen demand（SOD）,and fluxes of inorganic nitrogen compounds were investigated with N2.flux method,using a self-designed continuous flow through and auto-sampling *** results indicate that the denitrification rates varied between 2.2.and 908 μmol/（m2.h） with an average of 4.9 μmol /（m2.h）.During incubation,the sediments absorbed dissolved oxygen in the overlying water with SOD ranging from 3.0 to 2.3.3.μmol/（m2.h）.The denitrification rates were highly correlated with the SOD（r2.0.77） regardless of the NO-3.NO-2.concentrations in the overlying water,organic carbon contents in sediments and water temperature,suggesting that the SOD was probably the main environmental factor controlling the denitrification in the Qi＇ao Island coastal *** was a net flux of NO-3.NO-2.into the sediments from the overlying *** NH＋4.flux from sediments into water as the result of mineralization was between 12.3.and 2.0.3.μmol/（m2.h）,which seems limited by both organic carbon content in sediment and dissolved oxygen concentration in the overlying water.

关键词： denitrification N2.flux SOD inorganic nitrogen compound Qi' ao Island coastal zone Zhu-jiang Estuary

Characteristics of fluid inclusion planes and dynamical mechanism of structure-fluid-ore-forming processes in Yindongpo gold deposit, Henan Province, china

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chinese Science Bulletin 1999年第S2期44卷 150-152页

作者： WEI Changshan~1, ZHAI Yusheng~2.and GHI Sanchuan~2.1. Yichang institute of geology and Mineral Resources, {2. Academy of Geoscience, Yichang 4.3.03.{3. 2.{3. University of Geosciences, Beijing 100083.{3. Yichang institute of geology and Mineral Resources Chinese Academy of Geoscience Yichang 443003 China china University of Geosciences Beijing 100083 China

THE Yindongpo gold deposit, situated in northern Tongbei County, northern Qinling orogenic belt, is alarge-scale one controlled by the Heqianzhuang anticline that plunges northwestwards and dips northeastwards. The ore-bodies locates in the carbon layers belonging to the Neoproterozoic Waitoushan *** ore-forming periods can be distinguished: the pre-Mesozoic epithermal mineralization in primary sediment with metamorphic superposition and the Mesozoic epithermal-mesothermal mineralization related totectonomagmatic activities. The principal ore-forming period can be divided into four stages. The ore bodies consist of networked and brecciated quartz veins. Gold is mainly rich in the veinlet-type quartz veinsthat formed during the diagentic-metamorphism or syn-metamorphic hydrothermal period, but a little inthe coarse veins related to later tectonomagmatic activities. The phenomenon that the fracturing degree

关键词： fluid inclusion planes dynamical mechanism structure-fluid-ore-forming processes gold deposit Yindongpo Henan.

The crystal structure of (Fe_(4.Cr_(4.Ni)_(9)C_(4.

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Science china Earth Sciences 2005年第3期48卷 338-345页

作者： SHI Nicheng1, MA Zhesheng1, XIONG Ming1, DAI Mingquan1, BAI Wenji2. FANG Qingsong2. YAN Binggang2.& YANG Jingsui2.1. X-ray Diffraction Laboratory,{4. University of Geosciences, Beijing 100083.{4. 2. institute of {3., chinese Academy of Geological Sciences, Beijing 10003.,{4. 1. X-ray Diffraction Laboratory China University of Geosciences 100083 Beijing China 2. institute of geology Chinese Academy of Geological Sciences 100037 Beijing China

(Fe4.r4.i)9C4.is a metal carbide mineral formed by combination of Fe, Cr and Ni with C. It occurs in a chromite deposit in the Luobusha ophiolite, Tibet. Based on the determina- tion of its crystal structure, the empirical formula is (Fe4.12.r3.84.i0.96)8.92.3.70 and the simplified formula is (Fe4.r4.i)4.9. The mineral is hexagonal with a = 1.3.3.2.2. nm, c = 0.4.690(9) nm, space group P63.m c, Z=6 and the calculated specific gravity Dx = 7.089 g/cm3. Fe, Cr and Ni occupy different crystallographic sites and their coordination numbers are approximately 12. forming an alternate stacking sequence of flat and puckered layers along the c axis. Some me- tallic atoms have a defect structure. The interatomic distances of Fe, Cr and Ni are 0.2.2.— 0.2.66 nm, and the distances between Fe, Cr, Ni and C are 0.1893.0.2.69 nm. The coordina- tion number of carbon is 6. It occurs in interstices of the metallic atoms Fe, Cr and Ni to form trigonal-prismatically coordinated polyhedra. These coordination polyhedra are linked with each other via shared corners or shared edges into a new type of metal carbide structure.

关键词： Luobusha of Tibet, metal carbide, crystal structure.

The high-resolution climate recorded in the δ^(18)O of Porites lutea from the Nansha Islands of china

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chinese Science Bulletin 2001年第24期46卷 2097-2102页

作者： YU Kefu, CHEN Tegu, HUANG Dingcheng, ZHAO Huanting, ZHONG Jinliang & LIU Dongsheng (LIU Tungsheng)South china Sea institute of Oceanoiogy, {2. Academy of Sciences. Guangzhou 5103.1, china:geology and geophysics institute. {2. Academy of Sciences, Beijing 10002., china South china Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China geology and geophysics {2. Chinese Academy of Sciences Beijing China

A Porites lutea core from Yongshu Reef of Nansha Islands covering 50 years growth history was ana-ly/ed for oxygen isotopic composition with monthly and seasonally resolution. The calibration of the δ18O with the instrumental temperature indicated that the coral δ18O is a good indicator for sea surface temperature (SST) and air temperature (t). It can be used to reconstruct the SST and air temperature of the Yongshu Reef sea area. In addition, the coral δ18O provides signatures for the intensity of the East Asia monsoon and it is a record for the activities of El Nino events. With the calibrated SST and air temperature formulas, the most recent fifty years SST and air temperature were reconstructed based on the coral δ18O, thus back up the understanding of the climate of Nansha Islands to 1950. far beyond the limit of the instrumental recording since September 1988. It was found that, in general, increasing 1℃ air temperature results in 0.2.‰decrease in skeletal δ18O.

关键词： Nansha Islands Porites lutea δ18O sea surface tem-perature East Asia monsoon.