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Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science china Earth sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2, JI Junfeg3, WANG Xiaoyong1,7, ZHAO Jingbo4. HUANG Baochun5 & LI Zhen6 1. SKLLQG, institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 2. Department of Urban and Resources sciences, Nanjing University, Nanjing 210093, china 3. Department of Earth sciences, Nanjing University, Nanjing 210093, china 4. Department of Geography, Shaanxi Normal University, Xi’an 710062, china 5. institute of geology and geophysics, chinese academy of sciences, Beijing 100029, china 6 Department of Geography, Qinghai Normal University, Xining 810008, china 7. Graduate School of the chinese academy of sciences, Beijing 100039, china 1. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 7. Graduate School of the chinese academy of sciences Beijing 100039 China 2. Department of Urban and Resources sciences Nanjing University Nanjing 210093 China 3. Department of Earth sciences Nanjing University Nanjing 210093 China 4. Department of Geography Shaanxi Normal University Xi’an 710062 China 5. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China 6. Department of Geography Qinghai Normal University Xining 810008 China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 25 visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the chineseLoess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 11.4.Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

Orogen-parallel extension in Himalaya: Is it the indicator of collapse or the product in process of compressive uplift?

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chinese Science Bulletin 2000年第2期45卷 114-120页

作者： ZHANG Jinjiang, DING Lin, ZHONG Dalai & ZHOU Yong institute of geology and geophysics. chinese academy of sciences. Beijing {4., china institute of geology and geophysics Chinese Academy of Sciences Beijing China

Extensional structures developed extensively in Himalaya with their strikes perpendicular to that of the orogenic belt. The studies of such structures in Qusum, Burang, Lhozhag, Nyalam and Yadong show that they represent an orogen-parallel extension. The basins produced by the extension experienced orokyn-perpendicular compression during their formation. The ages of the extension rang from 16 to 13 Ma and coincide with the intensive compressive stage in Southeastern Asia. Therefore, the extension is Syn-shortening and the dominate tectonic movement in Himalaya was compression and uplift during the extension. The extension was the partition of compressive deformation rather than the indicator for the collapse and falling of the Tibetan Plateau.

关键词： Himalayan orognic helt syn-shortening extension uplift

Effects of the grain size distribution on the temperature-dependent magnetic susceptibility of magnetite nanoparticles

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Science china Earth sciences 2010年第7期53卷 1071-1078页

作者： ZHAO XiangYu1,2 & LIU QingSong1 1 Paleomagnetism and Geochronology Laboratory (SKL-LE), institute of geology and geophysics, chinese academy of sciences, Beijing {4., china 2 Graduate University of chinese academy of sciences, Beijing 10004., china 1. Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Magnetite is an important magnetic remanence carrier in natural samples and therefore is of great interest in paleo-, rock-, and environmental magnetism. The magnetic properties of magnetite depend on many factors, e.g., concentration and grain size distribution (GSD). In this study, we theoretically investigated the temperature-dependent susceptibility (TDS) of magnetite nanoparticles with a lognormal GSD. Results show that the TDS is affected highly by the GSD mainly in three aspects. Firstly, the unblocking process becomes smoother with the increase of distribution width, characterizing as a wider Hopkinson peak on the TDS curve. Secondly, the blocking temperature increases with the increase of the median diameter or/and the distribution width. Thirdly, the maximum susceptibility decreases with the increase of distribution width, and has a logarithmic function relation with the standard deviation of the distribution. As a case study, this model was further applied to the thermal products of the chinese loess/paleosol samples to determine the granulometry of newly-formed magnetite upon heating based on TDS curves. The results demonstrate the fidelity and feasibility of this method to determine the GSD of nano-sized magnetic particles.

关键词： Néel theory temperature dependence of susceptibility grain size distribution

Characteristics of the Middle-Late Triassic sedimentary facies assemblages in the Songpan-Ruoergai area

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Progress in Natural Science:Materials International 2007年第3期17卷 305-313页

作者： YAN Zhen, YU Liangjun, LI Jiliang, BIAN Qiantao, WANG Zongqi and YANG Yongcheng ( institute of geology, chinese academy of Geological {4., Beijing 100037, china State Key Laboratory of Lithospheric Evolution, institute of geology and geophysics, chinese academy of sciences, Beijing 100029, china Shaanxi Insititute of geology Survey, Xianyang 712000, china) [a]institute of geology Chinese Academy of Geological Sciences Beijing China [b]State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China [c]Shaanxi Insititute of geology Survey Xianyang China

The Middle-Late Triassic sedimentary rocks in the Songpan-Ruoergai area mainly consist of calcareous siltstone, muddy limestone, lithic arkose, feldspathic litharenite, mudstone, wormkalk, oolithic limestone, and conglomerate. Except for limestone bed increasing eastward longitudinally and vertically, the calcareous component of the sandstones increases obviously. Abundant benthic and plant fossils and their clasts occur within these rocks. The sedimentary structures predominately contain flaser, parallel, tabular, wavy, and herringbone cross beddings. These data coevally imply that the Middle-Late Triassic sediments deposited in the fluvial, lake and tide environments. Additionally, the rocks display graded, parallel, hummocky beddings, and sandy lamination, a feature characteristic of storm deposits.

关键词： Middle-Upper Triassic fluvial-lake environments tide environment tempestite Songpan-Ruoergai

Cenozoic terrestrial palynological assemblages in the glacial erratics from the Grove Mountains, east Antarctica

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Progress in Natural Science:Materials International 2009年第7期19卷 851-859页

作者： Aimin Fang a, Xiaohan Liu b, Weiming Wang c, Feixin Huang b, Lianjun Yu a a institute of geology and geophysics, chinese academy of sciences, Beijing {4., china b institute of Tibet Plateau Research, chinese academy of sciences, Beijing {4., china c Nanjing institute of geology and Palaeontology, chinese academy of Science, Nanjing 210008, china [a]institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China [b]Institute of Tibet Plateau Research Chinese Academy of Sciences Beijing 100029 China [c]Nanjing Institute of Geology and Palaeontology Chinese Academy of Science Nanjing 210008 China

Fossiliferous glacial erratics have been found in moraines of the Grove Mountains, east Antarctica since 1998 by chinese National Antarctic Research Expedition (CHNARE) teams. These erratics were derived from a suite of glaciogene strata hidden beneath the Antarctic Ice Sheet in the Lambert glacier drainage system, and thus provide a record of Cenozoic paleoenvironmental conditions and fossil biotas that are so far unknown from outcrops and drill cores in this region. By microfossil analysis, sparse Neogene spores and pollen grains are revealed, including: Toroisporis (Lygodiaceae), Granulatisporites (Pteridaceae?), Osmunda (Osmundaceae), Polypodiaceae, Magnastriatites (Parkeriaceae), Deltoidospora, Araucariaceae, Taxodiaceae, Podocarpus (Podocarpaceae), Dacrydium (Podocarpaceae), Pinus (Pinaceae), Keteleeria (Pinaceae), Picea (Pinaceae), Tsuga (Pinaceae), Chenopodiaceae, Artemisia (Asteraceae), Asteraceae, Gramineae, Fraxinoipollenites (Oleaceae), Oleoidearumpollenites (Oleaceae), Oleaceae, Operculumpollis, Nothofagidites (Nothofagus), Rhus, Quercus (Fagaceae), Juglans (Juglandaceae), Pterocarya (Juglandaceae), Liquidambar (Hamamelidaceae), Ulmus (Ulmaceae), Ulmoidepites (Ulmaceae), Tilia, Proteacidites (Proteaceae) and Tricolpopollenites; but without any marine diatoms. Most of the spores and pollen grains in the erratics are considered to originate from local sources except for some older exotic components that might be recycled from the basement sedimentary rocks by the ice sheet, so they are in situ sporo-palynological assemblages. Furthermore, since the source areas of the glaciogenic sedimentary rocks are assumed to be local or in the up glacier areas, the palynological assemblages in these erratics represent an inland terrestrial flora during a warmer period of the ice-sheet evolutionary history. The ages of these erratics are also discussed based on the occurrence of some diagnostic pollens such as the Artemisia, Chenopodiaceae and Nothofagus, which implies

关键词： East Antarctica Grove Mountains Glacial erratics Spores and pollen Neogene

Carbon isotopic variations of Proterozoic carbonates in Jixian, Tianjin, china

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Science china Earth sciences 2004年第2期47卷 160-170页

作者： CHU Xuelei, ZHANG Tonggang, ZHANG Qirui, FENG Lianjun & ZHANG Fusong1. institute of geology and geophysics, chinese academy of sciences, Beijing {4., china 2. Key Laboratory for Mineral Resources Research, chinese academy of sciences, Beijing {4., china Correspondence should be addressed to Chu Xuelei (email: xlchu@***) 1. institute of geology and geophysics Chinese Academy of Sciences 100029 Beijing China 2. Key Laboratory for Mineral Resources Research Chinese Academy of Sciences 100029 Beijing China

Along the Proterozoic stratigraphic sections of Jixian, Tianjin, the ??13C values of carbonates are mostly negative in the Changchengian (Changcheng System), varying approximately within a range of (0±1)‰ in the Jixianian (Jixian System), and have commonly positive values of (2±2)‰ in the Qingbaikouan (Qingbaikou System). From Chuanlinggou Formation to Dahongyu Formation, i.e. from ca. 1700 Ma to 1600 Ma, the δ13C values of carbonates increase from about -3‰ to 0‰, but oscillate with large excursion in Dahongyu Formation. Two large excursions occur in the Jixianian, one in Yangzhuang Formation and the other in the third submember of Wumishan Formation overlaying. These integrated and continuous records of carbon isotope reflect secular variations of δ13C value in ancient seawater from ca. 1700 Ma to ca. 800 Ma. The increase and subsequent oscillation of seawater δ13C value occurring from the ages of ca. 1700 to ca. 1600 Ma and ＜1300 Ma may signify two correlative global tectonic events.

关键词： Proterozoic, Jixian, carbon isotope, chemostratigraphy, secular variation, global tectonic event.

Mineralization episode of porphyry copper deposits in the Jinshajiang-Red River mineralization belt: Re-Os dating

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Science china Earth sciences 2005年第2期48卷 192-198页

作者： WANG Denghong, QU Wenjun, LI Zhiwei, YIN Hanlong4.& CHEN Yuchuan institute of Mineral Resources, chinese academy of Geological sciences, Beijing 100037,{4. National Center of Rock and Mineral Analysis, chinese academy of Geological sciences, Beijing 100037,{4. Resource Assessment Center of Yunnan, Kunming 650011,{4. institute of geology and geophysics, chinese academy of sciences, Beijing 100101,{4. chinese academy of Geological sciences, Beijing 100037,{4. 1. institute of Mineral Resources Chinese Academy of Geological Sciences 100037 Beijing China 2. National Center of Rock and Mineral Analysis Chinese Academy of Geological Sciences 100037 Beijing China 3. Resource Assessment Center of Yunnan 650011 Kunming China 4. institute of geology and geophysics Chinese Academy of Sciences 100101 Beijing China 5. chinese academy of Geological sciences 100037 Beijing China

Re-Os isotopic dating for the molybdenites from the porphyry copper deposits of the Jinshajiang-Red River mineralization belt in Yunnan Province yields isochron ages of 33.9±1.1 Ma for the Machangqing deposit and 34.4.0.5 Ma for the Tongchang deposit. This result shows that both the Machangqing and the Tongchang porphyry Cu-Mo deposits from two different ore-fields formed simultaneously. This new data and the published Re-Os model ages of molybdenite (35.4.Ma, 35.9 Ma, 36.2 Ma) of the Yulong porphyry copper deposit in Tibet, which is located in the same Jinshajiang-Red River mineralization belt as the Machangqing deposit and the Tongchang deposit, suggest that these three Cenozoic porphyry copper deposits in the Jinshajiang-Red River mineralization belt were contemporary for their mineralization episode. That is to say, even their present locality is far away and nearly iso-distantly distributed, these three porphyry Cu(Mo) deposits belong to the same mineralization episode at the end of Eocene.

关键词： Re-Os isotopic dating, porphyry Cu deposits, Cenozoic, mineralization episode.

Principles and methods of quantitative analysis on b-axis disorder in 2 : 1 dioctahedral phyllosilicate

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chinese Science Bulletin 1997年第22期42卷 1908-1912页

作者： WANG Ling and ZHANG Zhenyu1. Changsha institute of Geotectonics, chinese academy of sciences, Changsha 4.0013, china 2. institute of {4., chinese academy of sciences, Beijing 100029, china Changsha institute of Geotectonics Chinese Academy of Sciences Changsha China institute of geology Chinese Academy of Sciences Beijing China

IN XRD patterns of clay minerals, a phenomenon that strong peaks often have (00l) and(hkl) (k=3n) indices and show symmetric figures can be seen commonly, while a minorityof reflection peaks (hkl) (k≠3n) are comparat... 详细信息

关键词： b-axis disorder pyrophvllile 2 phyllosilicate clay minerals dioctahedral minerals orientating structure of hy-droxyls crystal structure analysis DTA-TG.

Mid-Holocene climate change in North china, and the effect on cultural development

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chinese Science Bulletin 2002年第5期47卷 408-413页

作者： JIN Guiyun & LIU Dongsheng (LIU Tungsheng)institute of Cultural Relics and Archaeology of Shandong Province, Jinan 250012, china institute of geology and {4., chinese academy of sciences, Beijing 100029, china institute of Cultural Relics and Archaeology of Shandong Province Jinan China institute of geology and geophysics Chinese Academy of Sciences Beijing China

In this study, to reconstruct the paleoclimatic history, pollen and oxygen isotope were analyzed on the 160 samples of a 2.7 m peat core from Taishizhuang, Huailai County, Hebei Province. Combining our data with other information of climate history and archaeology from this area, we found that there is a close linkage between cultural development and the mid-Holocene (6000-3000 cal. aBP) environment changes. The main results and conclusions are presented as the following: The climate during 5678-54.0 cal. aBP was unstable and in general colder and drier than today. From 54.0 to 4.00 cal. aBP the climate was much warmer and wetter than before. The climate during 4.00-4.00 cal. aBP was persistently cold, with an exceptional cold event occurring at 4.00-4.00 cal. aBP. This cold event was recorded at several other localities in Northern china even the Northern Hemisphere and played an important role in the cultural development. After the cold event, there was a return to warmer conditions between 4.00 and

关键词： North china peat mid-Holocene cold event cultural development.