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

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Acta Geologica Sinica(English Edition) 2001年第4期75卷 391-397页

作者： wu Genyao Institute of geology and Geophysics,{2., beijing 100029 Institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 [?]2.0} Genyao Male born in 1946 graduated from the Department of geology Peking University in 1968 obtained a DSc degree in 1985 now a research professor with the Institute of geology and Geophysics Chinese Academy of Sciences. His main research interest is regional tectonics and he has been working on the tethysides in South China and adjacent areas since 1987. Tel: (010) 62008118 Fax: (010) 62.10846 E-mail: dizhikx@***

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 subcontinent. The Indosinian foreland fold-and-thrust belt bordering Yunnan and Guangxi provided further evidence for the palaeotethysides. 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 northeast. The 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

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 Geophysics,{2., 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

Jinning granodiorite and diorite deeply concealed in the central Tarim Basin

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Science china Earth sciences 2005年第12期48卷 2061-2068页

作者： LI Yuejun1, 2. SONG Wenjie2. wu Genyao1, WANG Yifen1, LI Yuping2.& ZHENG Duoming2.1. Institute of geology & Geophysics,{2., beijing 100029. china 2. Tarim Oil-field Company, Petrochina, Korla 841000, china 1. Institute of geology & Geophysics Chinese Academy of Sciences 100029 Beijing China 2. Tarim Oil-field Company 841000 Korla PetroChina China

The 72.0-m-deep Well Tacan 1 in the central Tarim Basin is the deepest in china. Purplish gray medium-grained granodiorite containing dark gray fine-grained diorite xenolith is revealed at the base of the well (7169―72.0 m), and they are results of the Jinning magmatic activities. Trace-element geochemistry and REE profiles of both rock types are similar, indicating that they are calc-alkaline series I-type granitoid. Proxies of diorite signify the development of a magmatic arc due to subduction at ca. 12.0 Ma. The granodiorite was formed before 890―932.Ma. However, more study is needed to clarify if the arc diorite represents a ca. 300 Ma extension of the subduction or a reactivation during the orogenic collision event at ca. 900 Ma.

关键词： diorite, granodiorite, magmatic arc, Jinning orogeny, Tarim Basin.

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 Geophysics,{2., 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 FLAC3D, 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.

Tectonic setting of the Helong Block:Implications for the northern boundary of the eastern North china Craton

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Science china Earth sciences 2005年第10期48卷 1599-1612页

作者： ZHANG Yanbin1, wu Fuyuan1, ZHAI Mingguo1 & LU Xiaoping1,2.1. Institute of geology and Geophysics,{2., P.O. Box 982., beijing 100029. china 2. Regional Geological and Mineral Resources Survey of Jilin Province, Changchun 130062. china Institute of geology and Geophysics chinese academy of sciences {2. china Regional Geological and Mineral Resources Survey of Jilin Province Changchun china

LA-ICP-MS zircon U-Pb dating indicates that the Bailiping granitic pluton was em-placed during Late Paleozoic to Early Cretaceous (2.5―116 Ma) by four distinct magmatic epi-sodes, arguing against the previous thought that the Bailiping granites were emplaced during Archean, Proterozoic or Early Paleozoic. It is suggested that the so-called Archean Jincheng-dong granite-greenstone belt, mainly composed of Bailiping granites, should be broken down. Sr-Nd isotopic compositions of the Bailiping granites are similar to those of the Phanerozoic granites in the Xing’an-Mongolian orogenic belt, suggesting that their parental magmas were mainly derived from a juvenile crust with some contamination of ancient crustal materials during magma rising and/or emplacement. Therefore, the basement of the Helong Block is similar to that in the northern Xing’an-Mongolian Orogenic Belt, but different from that of the North china Craton. It is proposed that the Archean Jinchengdong complex in this area is probably an exotic slice from the North china Craton, which indicates that the Fu’erhe-Gudonghe Fault, located in northern part of the Helong area, is not the boundary between the North china Craton and the Xing’an-Mongolian Orogenic Belt. The possible boundary should be located further southward more than 50 km and near the Baitoushan volcano.

关键词： LA-ICPMS ziron U-Pb dating, Bailiping complex, Helong Block, North china Craton, Sr-Nd isotope.

Carbon isotope ratios of C_(4) plants in loess areas of North china

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Science china Earth sciences 2006年第1期49卷 97-102页

作者： WANG Guoan1,2.3, HAN Jiamao 2. ZHOU Liping3, XIONG Xiaogang4, TAN Ming2. wu Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, china Agricultural University, {2. 100094, china 2. Institute of geology and Geophysics, chinese academy of sciences, beijing 100029. china 3. College of Environmental sciences, MOE Laboratory for Earth Surface Processes, Peking University, {2. 100871, china 4. Institute of Botany, chinese academy of sciences, {2. 100093, china 5. Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712.00, china 6. Network Center, china Agricultural University, {2. 100094, china 1. Department of Plant Nutrition China Agricultural University Beijing 100094 China 2. Institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 3. College of Environmental sciences MOE Laboratory for Earth Surface Processes Peking University Beijing 100871 China 4. Institute of Botany Chinese Academy of Sciences Beijing 100093 China 5. Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 China 6. Network Center China Agricultural University Beijing 100094 China

Carbon isotope ratios (δ^(13)C) of 89 C_4 plant samples were determined fromthe loess area in North china. δ^(13)C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13)C values of C_4 plants show a slight decreasingtrend. The δ^(13)C values of C_4 plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3 species.

关键词： C4 plants, carbon isotope ratios, loess area.

Slope Reinforcement for Housing in Three Gorges Reservoir Area

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Journal of Mountain Science 2011年第2期8卷 314-320页

作者： wu Faquan LUO Yuanhua CHANG Zhonghua Institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Office of Three Gorges Project Construction Committee the State Council of China Beijing 100038 China

The Three Gorges Project of the Yangtze River is the largest hydropower-complex project under construction in the world. Under the largescale relocation projects, 2.74 engineered slopes are formed along with the construction of new towns. In this paper, the cutting slopes are mainly soil slopes and rock slopes. Soil slopes include residual soil slopes, colluvial accumulation slopes, swelling soil slopes, and artificial earth fill slopes, etc. Rock slopes include blocky structure rock slopes, layer structure rock slopes, and clastic structure rock slopes, etc. Varied protection measures have been used for slope protection in the reservoir area including shotcrete concrete-anchor bars, frame beams, retaining walls, slope stabilizing piles, sheet-pile walls, anchorage anti-shear tunnels, flexible protection grids, and drainage, etc. Besides, slope deformation monitoring systems have been set up to monitor deformation failure and the stability state of slopes. The protection measures have guaranteed slope safety and maintained a harmony with the urban environment and surrounding landscape.

关键词： Slope reinforcement Housing for resettlement Three Gorges Reservoir

Lithosphere types in North china:Evidence from geology and geophysics

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Science china Earth sciences 2005年第11期48卷 1809-1827页

作者： QIU Ruizhao1,2, DENG Jinfu3, ZHOU Su3, LI Jinfa4, XIAO Qinghui1,5, wu Zongxu6 & LIU Cui3 1. Institute of geology, chinese academy of Geological sciences, beijing 100037, china 2. Development and Research Center, china Geological Survey, beijing 100037, china 3. china University of Geosciences, beijing 100083, china 4. china University of Geosciences, wuhan 430074, china 5. Information Center of Ministry of Land and Resources, beijing 100812, china 6. Institute of geology, State Seismological Bureau, beijing 100029. china 1. Institute of geology Chinese Academy of Geological Sciences 100037 Beijing China 2. Development and Research Center China Geological Survey 100037 Beijing China 3. china University of Geosciences 100083 Beijing China 4. china University of Geosciences 430074 Wuhan China 5. Information Center of Ministry of Land and Resources 100812 Beijing China 6. Institute of geology State Seismological Bureau 100029 Beijing China

On the basis of the characteristics of geology and geophysics in North china, three types of lithosphere, namely, the cratonic, the orogenic and the rift lithospheres can be classified. In terms of petrological method (based on the information from Precambrian rock assemblages, igneous activities, deep-seated enclaves, etc.) and the relationship between seismic velocity and rock compositions, the crust-mantle petrological and chemical structure models can be set up. Researching results indicate that the geology and geophysics of North china platform bears the similar characteristics in comparison with those of the global typical cratons. The Eerduosi(Ordos) block located in the west of the North china Platform is a remnant of cratonic lithosphere after the North china platform had undergone “activation” in Mesozoic and “reconstruction” in Cenozoic times. The continental crust consists mainly of TTG rock assemblage while the subcontinental lithosphere mantle mainly consists of strongly depleted harzburgite. The craton was finally formed in late Archaean and early Proterozoic, and has been kept in stability up to present; its crustal-mantle petrological structures of lithosphere can be set up as a reference for the study of North china craton and even Sino-Korean craton. In the Mesozoic period, the middle and east areas of North china platform were activated in the Yanshanian orogenic process, the continental crust was reformed by material and heat-transfer of convective mantle and the original crustal TTG component was reconstructed to be granitic crust, and the subcontinental lithosphere man- tle was replaced by the Yanshanian harzburgite-lherzolite. The Yanshan-Taihang Mountains were the remnants of orogenic lithosphere after the rifting in eastern North china in Cenozoic. The present thickness of continental crust and lithosphere in the Yanshan-Taihang Mountains is not equal to their thickness during the Yanshanian orogenic movement because they had undergone the

关键词： lithospheric types,evidence of geology and geophysics,crust-mantle petrological structure,deep process

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, {2. 100101, china Department of Civil Engineering, Hong Kong University, Hong Kong, china 3. Institute of geology 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.