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Quantitative Evaluation of the Sea-level Drop at the End-Permian: Based on Reefs

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Acta Geologica Sinica(English Edition) 2003年第1期77卷 95-102页

作者： wu Yasheng and FAN Jiasong institute of geology and {3., chinese academy of sciences, Beijing 100029 chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

The amplitude of pre-Quaternary sea level drop, H, can be calculated by usingthe formula H = D + To, where To is the original thickness from the top of the tidal deposits onthe reef core to the bottom of the tidal deposits on the reef front, or to the bottom of the ancientmeteoric vadose zone, or to the edge of the mixed-water dolostone zone. The identity and similaritybetween the sea-level drop amplitudes calculated from different reefs far away from each otherindicates that such sea-level changes are eustatic rather than relative changes. Evidence of anend-Permian sea-level drop has been found on the Changxingian (i.e. the end of the Palaeofusulinazone) reefs at Ziyun in South China, including algal laminated deposits, sabkha-related dolostone,desiccation cracks, dissolution collapse breccia. According to calculation based on the meteoricdissolution zone of the reef-core sequence at Ziyun, Guizhou province, the amplitude of thesea-level drop at the end-Permian is about 89.3.m. Calculation via the dolomitized upper part of theChangxingian reef in Lichuan, Hubei Province, yields an 88.9 m amplitude of the sea-level drop atthe end-Permian. Comparison shows that the sea-level drop recorded in the two distantly locatedreefs may be of eustatic type. So the amplitude of the sea level drop of the Tethys Sea at theend-Permian might be at least 89.3.m.

关键词： sea-level drop eustatic reef Permian Changxingian

Reinterpretation of the Guangxian Orogeny

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chinese Science Bulletin 2000年第13期45卷 1244-1248页

作者： wu Haoruoinstitute of geology and {3., chinese academy of sciences, Beijing 100029, China institute of geology and geophysics Chinese Academy of Sciences Beijing China

The Guangxian Orogeny, as an important concept on geology of South China, was created 70 years ago. It is generally regarded as an erogenic movement caused by the convergence of the Cathaysian and Yangtze blocks at the end of Silurian. Based on the recent progress of the geological research on Guangxi and adjacent areas, western Guangxi and Liuzhou-Heshan area of central Guangxi may belong to a stable block of Early Paleozoic. The Guangxian Orogeny originated from the northward translation of the Yunkai Block on its south at the end of Cambrian, and formed the Damingshan-Dayaoshan fold belt between the two blocks. It was possibly related with the Late Pan-African Orogeny. The convergence of the Cathaysian and Yangtze blocks occurred in Late Ordovician to Early Silurian and mainly had effect on Hunan and Jiangxi provinces. The term 'Chongyu Orogeny' may be suitable for it. At the end of Silurian orogenic movement did not occur in this area.

关键词： South China tectonics Paleozoic Guangxian Orogeny Yunan Orogeny Chongyu Orogeny.

Discovery of Cathaysiodendron Lee from the Early Carboniferous of Jingyuan,Gansu,western China

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Progress in Natural Science:Materials International 2004年第10期14卷 63-66页

作者： WANG Jun and wu Xiuyuan (Nanjing institute of geology and Palaeontology,{3. {3. of sciences,Nanjing210008,China) Inst. of Geol. and Paleontology Chinese Acad. of Sci. Nanjing 210008 China

As one of the representative members of the Late Palaeozoic Cathaysian flora,Cathaysiodendron has been previously recorded from the Early Permian Taiyuan and Shanxi Formations in north *** species of Cathaysiodendron presented here are from the lower member of Chouniugou Formation of Ciyao,Jingyuan,*** overlying marine beds yield fusulinids that are of Visean age in western Europe and conodonts of the Datang Stage in south China,so that the age of the bed containing Cathaysiodendron as Visean,Early Carboniferous,is well *** a record of Cathaysiodendron is significant in terms of Carboniferous phyto-geography and the evolution of the Cathaysian Lepidophytes.A new species,Cathaysiodendron jingyuanense Wang&wu *** described and a second one mentioned.

关键词： Cathaysiodendron Early Carboniferous Visean Cathaysian flora

Environmental characteristics of Mid-Holocene recorded by lacustrine sediments from Lake Daihai, north environment sensitive zone, China

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Science China Earth sciences 2006年第9期49卷 968-981页

作者： SUN Qianli1,2, ZHOU Jie1, SHEN Ji3. CHEN Peng1,2, wu Feng1,2 & XIE Xiuping1,2 1. State Key Lab of Loess and Quaternary geology, institute of Earth Environment,{3., Xi’an 710075, China 2. Graduate University of{3., Beijing 10003., China 3. Nanjing institute of Geography and Limnology,{3., Nanjing 210008, China State Key Lab of Loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of chinese academy of sciences Beijing China Nanjing institute of Geography and Limnology Chinese Academy of Sciences Nanjing China

Climate proxies, such as total organic carbon and nitrogen (TOC, TN), carbonate content (CaCO3., grain-size and pollen of the sediment core retrieved from enclosed Lake Daihai which lies in the north China environment sensitive zone are analyzed to reconstruct the environment evolution of the area based on high-resolution radiocarbon chronology. The results reveal that the TOC and TN contents of the sediments correlate well with pollen percentage and pollen flux variations during the Holocene, and both reach their peak values simultaneously at 6.7―3.5 ka BP (calendar age, 7.6―3.6 ka BP). Since 6.7 ka BP, both the CaCO3.and organic matter contents of the core have simultaneous variations, and their high values also occur during 6.7―3.5 ka BP. While during 9.0―6.7 ka BP (calendar age, 10―7.6 ka BP) relatively lower level of organic matter content and pollen flux corre- spond to the higher level of carbonate content. The above relations suggest that during 6.7―3.5 ka BP, the productivity and effective precipitation were greatly improved in the lake drainage area, and this would probably strengthen the hydrodynamic conditions, enhancing organic matter, pollen and carbonate inputs from terrestrial sources. Such processes would account for the enrichment of both organic matter and carbonate in the sediments. While during 9.0―6.7 ka BP, the lower level of or- ganic matter, pollen flux but high carbonate content show depressed productivity and declined vege- tation coverage. The higher carbonate content at this stage would have probably resulted from the higher evaporation ratio of the lake water under relatively drier climate conditions. Therefore, it is in- ferred that during 6.7―3.5 ka BP, the climate was more humid with abundant rainfalls and vegetation was more flourishing in the Lake Daihai area. This can be seen as Holocene Climate Optimum (HCO). As a result, this has evident discrepancies with the traditional notion that the HCO occurs at Early Holocene or early Mid

关键词： Lake Daihai, Mid-Holocene, lacustrine sediments, environmental characteristics.

Rainfall-induced landslide stability analysis in response to transient pore pressure——A case study of natural terrain landslide in Hong Kong

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Science China(Technological sciences) 2003年第Z1期46卷 52-68页

作者： LAN Hengxing, ZHOU Chenghu C. F. LeeWANG Sijing & wu Faquan State Key Laboratory of Natural Resources and Environmental System, institute of Geographical Sci-ences and Natural Resources Research, chinese academy of sciences, Beijing 100101, China Department of Civil Engineering, Hong Kong University, Hong Kong, China 3. institute of {3. and geophysics, chinese academy of sciences, Beijing 100029, China chinese Acad Sci State Key Lab Nat Resources & Environm Syst Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China Univ Hong Kong Dept Civil Engn Hong Kong Hong Kong Peoples R China chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

Transient pore pressure in response to short intense rainfall process plays an important role in shallow landslide occurrence. Using GIS technology, we carry out the rainfall-induced landslide stability analysis in response to transient pore pressure by means of transient and unsaturated rainfall infiltration modeling. A case study is performed on the shallow landslide stability analysis in Hong Kong. Detailed analysis and discussion reached some useful conclusions on the tempo-spatial behavior and characteristics of slope stability response and pore pressure response to typical rainfall process. Comparison analysis is performed on some important issues including landslide stability response in different types of slopes with different hydraulic properties, antecedent rainfall and landslide stability, and the nature of pore pressure response time. These studies might give us an important insight into landslide tringgering mechanism and the hydrological process in response to rainfall, and provide systematic information and evidences for effective risk assessment and warning system establishment.

关键词： rainfall-induced landslide, transient pore pressure, landslide stability in response to rainfall, GIS.

Indosinian Foreland Fold-and-Thrust Belt Bordering Yunnan and Guangxi,China

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Indosinian Foreland Fold-and-Thrust Belt Bordering Yunnan an...

Hydrogen isotopic characteristics and their genetic relationships for individual n-alkanes in plants and sediments from Zoigê marsh sedimentary environment

中国科学院地质与地球物理研究所2001学术年会

作者： wu genyao institute of geology and geophysics,chinese academy of{3.,Beijing 100029

Recent discoveries of ophiolites indicate that there must be a Palaeotethyan geosuture zone bordering China and Vietnam,which separates the Vietbac block from the South China *** Indosinian foreland fold-and-thrust belt bordering Yunnan and Guangxi provided further evidence for the *** oceanic crust was subducted southwestwards while the magmatic arc migrated northeastwards,and the continent-arc collision occurred in the Late Triassic with the thrusting being extended towards the north or *** features of thrust-nappe structure are discussed,which proved the continental margin of the Palaeotethyan ocean there to be a complicated one.A face-to-face collision occurred first along the NW-striking segment and then along the ENE-striking segment accompanied by transpression or oblique thrusting occurring along the NW-striking one.

关键词： thrust-nappe structure foreland fold-and-thrust belt palaeotethysides border between Yunnan and Guangxi

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Science China Earth sciences 2010年第9期53卷 1329-1334页

作者： DUAN Yi1, ZHENG ChaoYang2 & wu BaoXiang1 1 Key Laboratory of Petroleum Resources Research, institute of geology and {3., chinese academy of sciences, Lanzhou 73.000, China 2 Department of geology, Northwest University, Xi’an 710069, China Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou China Department of geology Northwest University Xi’an China

To understand internal relations of their hydrogen isotopic compositions in typical marsh environment, we, using GC-IRMS analytical technique, measured the hydrogen isotopes of individual n-alkanes in the herbaceous plant, woody plant leaf, and sediments from Zoigê marsh in China. The results show significant differences in the hydrogen isotopic compositions of n-alkanes among the different kinds of plants and the different species in the same kind. δD values of n-alkanes in the herbaceous plants (from -254‰ to -184‰) are lighter than those in woody plant leaf ( from -195‰ to -142‰ ), and the hydrogen isotopic compositions of n-alkanes in K. tibetica P. are lighter than P. pratensis L. The mean δD values of n-alkanes in the sediments from Zoigê marsh reflect that they were derived from herbaceous plants, which is consistent with the peat samples being composed mainly of herbaceous plant remnants. The significant differences in hydrogen isotopic compositions of n-alkanes among the sedimentary samples are caused possibly by environment factors and the difference in input quantity of different herbaceous plants. A certain negative correlation exists between the δ13. and δD values of n-alkanes in the samples, and plant types can be distinguished using the cross plot of δD vs. δ13. values of n-alkanes in the plants. These data and recognitions provide scientific basis for hydrogen isotopic applied research of individual n-alkanes.

关键词： marsh environment plants sediments individual lipids hydrogen isotopes genetic relationship

Dating of the Karakorum Strike-slip Fault

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Acta Geologica Sinica(English Edition) 2001年第1期75卷 10-18页

作者： ZHOU Yong, XU Ronghua, YAN Yuehua, PAN Yusheng,Tsanyao Frank YANG, Wei LO and wu Chunming Laboratory of Lithosphere Tectonic Evolution, institute of geology and {3., chinese academy of sciences, Beijing 100029Department of geology, National Taiwan University, 245 Choushan Road, Taipei 106-17, TaiwanDepartment of geology, chinese Culture University, Hwa-kang, Yang-Ming-Shan, Taipei, Taiwan institute of geology, chinese academy of Geological sciences, Beijing 10003. chinese Acad Sci Inst Geol & Geophys Lab Lithosphere Tecton Evaluat Beijing 100029 Peoples R China Natl Taiwan Univ Dept Geol Taipei 10617 Taiwan chinese Culture Univ Dept Geol Taipei Taiwan chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

This paper mainly discusses the timing of the Karakorum strike-slip fault, and gives a brief introduction of its structures, offset, and deformational style. This fault strikes NNW-SSE. Asymmetrical folds, stretching lineation, S-C fabrics, feldspar and quartz s?-porphyroclasts, domino structure, shear cleavages and faults in the fault zone are products of tectonic movements. They all indicate a dextral slip sense of faulting. Mylonitic bands are widely developed along this fault. Phengite appears, indicating rather high deformational pressure. Geochronological data indicate that the Karakorum strike-slip faulting occurred from 6.88±0.3. to 8.75±0.25 Ma. The cumulative displacement from Muztag Ata to Muji is about 13. km.

关键词： Karakorum fault kinematics timing displacement

General regularity of dynamic responses of slopes under dynamic input

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Science China(Technological sciences) 2003年第Z1期46卷 120-132页

作者： QI Shengwen, wu Faquan & SUN Jinzhong institute of geology and {3., chinese academy of sciences, Beijing 100029, China College of Engineering Technique, China University of Geosciences, Beijing 100083. China chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China China Univ Geosci Coll Engn Techn Beijing 100083 Peoples R China

Through lots of numerical simulations with FLAC3., dynamic responses of slopes are comprehensively studied in this paper and the general regularities of the isoline of the coefficient of the displacement, velocity and acceleration of the slope section are reached. Given a certain material slope, if the height of the slope is less than a certain value, the displacement, velocity and acceleration linearly enlarge with elevation in the vertical direction; if the height of the slope surpasses the certain value, the displacement,velocity and acceleration do not linearly enlarge with elevation any more, on the other hand, they fluctuate with a certain rhythm. At the same time, the rhythm appears in the horizontal direction, and the displacement, velocity and acceleration of the slope surface enlarge near the slope surface. The distribution form of the isoline of the coefficient of displacement, velocity and acceleration in the section of the slope is remarkably affected by the slope angle. In the certain area near the slope surface, the isoline of displacement,velocity and acceleration is parallel to the surface of the slope; in the mean time the strike direction of the extremum area is parallel to the surface of the slope, too. The charts of the slope dynamic responses can be depicted with two indexes, one is the strike direction of the isoline, and the other is the number of the rhythm extremum area of the direction parallel to the surface of the slope.

关键词： slope, dynamic response, regularity, rhythm.