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Progress and review of the studies on the end-Triassic mass extinction event

Science china Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2. LU Yuanzheng1,2.3 & XU Daoyi4 1. Research Institute of Petroleum Exploration and Development, beijing 100083. china 2. key laboratory of oil and gas reservoir of petrochina, beijing 100083. china 3. china University of Geosciences, beijing 100083. china 4. Institute of Geology, china Earthquake Administration, beijing 10002., china Research Institute of Petroleum Exploration and Development Beijing China key laboratory of {2. and gas reservoir of petrochina Beijing China china University of Geosciences Beijing China Institute of Geology China Earthquake Administration Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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Abnormal high pressure in Kuqa foreland thrust belt of Tarim basin: Origin and impacts on hydrocarbon accumulation

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Progress in Natural Science:Materials International 2006年第12期16卷 1307-1314页

作者： ZENG Lianbo~1** and LIU Benming~ 1,2.(1. key laboratory of Hydrocarbon Accumulation in {2. Petroleum University, Ministry of Education, beijing 102.49, {2. 2. The Institute of oil and gas Exploration and Development, Tarim oilfield Company, petrochina Company Limited, Korla 841000, {2.) key laboratory of Hydrocarbon Accumulation in {2. Petroleum University Ministry of Education Beijing 102249 China The Institute of oil and gas Exploration and Development Tarim Oilfield Company PetroChina Company Limited Korla 841000 China

Following analyses of the abnormal high pressure distribution characteristics, based on the geological characteristics, tectonic stress field and physical simulation, we investigated the formation mechanisms of abnormal high pressure and its impacts on hydrocarbon accumulation in the Kuqa foreland thrust belt. The abnormal high pressure appears at the bottom of the Paleogene and obviously exists in the Triassic and Jurassic. However, the pressure coefficient in the Triassic and Jurassic is lower than that in the Cretaceous and at the bottom of the Paleogene. Horizontally, the abnormal high pressure distribution is characterized by E-W orientation zoning. The maximum pressure coefficient lies in the Kelasu-Dongqiu-Dina tectonic zones in the center of the Kuqa foreland thrust belt and decreases away from the tectonic zones. The formation of abnormal high pressure was mainly related with the intense tectonic compression in the Early Pleistocene time, and tectonic uplifting, undercompaction and hydrocarbon generation were secondary factors contributing to abnormal high pressure. Under the rapid and intense tectonic compression in the Early Pleistocene, the rock framework firstly undertook 1/4 of the compression stress and the other was borne by the pore fluids. Due to the presence of great seal of gypsum-salt or gypsum-mudstone beds in the Paleogene, the pressure of pore fluids increased rapidly and led to the abnormal high pressure in the Kuqa foreland thrust belt. The abnormal high pressure has important impacts on hydrocarbon accumulation. It is one of the necessary conditions for formation of large oil and gas fields in the Kuqa foreland thrust belt.

关键词： abnormal high pressure formation mechanism oil and gas {2. Kuqa foreland thrust belt Tarim basin.

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Application of backflush and micro-flow techniques to the analysis of C5—C13 hydrocarbons in crude oils and its geochemical significance

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Progress in Natural Science:Materials International 2007年第11期17卷 1382-1387页

作者： Wang Peirong1,2. Zhao Hong2.3, Xu Guanjun1,4, Zhu Cuishan2.3, Xiao Tingrong4, Zhang Min2.3 and Zhang Bin1,4(1. key laboratory of Petroleum Geochemistry, {2. National Petroleum Corporation, beijing 100083. china 2. Geochemistry Department of Yangtze University, Jingzhou 43402., {2. 3. key laboratory of Exploration Technologies for oil and gas Resources, Ministry of Education, Yangtze University, Jingzhou 43402., {2. 4. Petroleum Geology Central laboratory, Research Institute of Petroleum Exploration and Development, petrochina, beijing 100083. china) key laboratory of Petroleum Geochemistry China National Petroleum Corporation Beijing 100083 China Geochemistry Department Yangtze University Jingzhou 434023 China key laboratory of Exploration Technologies for {2. and gas Resources Yangtze University Jingzhou 434023 China Petroleum Geology Central laboratory Research Institute of Petroleum Exploration and Development PetroChina Beijing 100083 China

An Agilent 6890N GC equipped with both FID and Agilent 5975 MSD analyzer has been employed to analyze C5—C13 hydrocarbon fractions of crude oils. A technical combination of program temperature volatilizer injection, backflush and micro-flow controller afforded a fine separation of C5—C13 compounds on a PONA column with the heavy part of crude oils being cut off before entering the analytical column. Both GC-FID chromatogram and GC-MS mass chromatograms (MID and full scan) could be obtained at the same time. The retension time differences of nC6—nC13 alkanes between GC and TIC were in the range of 0.02.0.58 minutes. Totally 2.6 peaks have been assigned group compositions. Results on 8 typical oil samples from CNPC key laboratory Crude oil Library showed that the characteristics of C6—C13 hydrocarbon group composition could be used in oil-oil correlation studies.

关键词： GC analysis GC/MS analysis backflush micro-flow controller light fraction in crude oil

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Science china Earth Sciences 2004年第10期47卷 896-911页

作者： ZHANG Changhou1,2. WU Ganguo1,2. WANG Genhou2. ZHANG Weijie2.& SONG Honglin2.1. key laboratory of Lithospheric Tectonics and Lithoprobing Technology, {2. University of Geosciences, Ministry of Education of {2., beijing 100083. china 2. School of Earth Sciences and Mineral Resources, {2. University of Geosciences, beijing 100083. china key laboratory of Lithospheric Tectonics and Lithoprobing Technology China University of Geosciences Ministry of Education of China Beijing China School of Earth Sciences and Mineral Resources China University of Geosciences Beijing China

The northwest trending tectonic belt in the middle part of the Mesozoic intraplate Yanshan Orogenic Belt, northeast Hebei Province, is composed of thrusts, extensional faults, strike-slip faults and syntectonic sedimentations as well. The northeastward basement-involved major thrusting deformation occurred between 174Ma and 168MaBP and was followed by an intrusion of the granitic plutonic rocks. As a part of the post-thrusting extensional deformations a northwest extending volcano-sedimentation system of Late Jurassic and Early Cretaceous formed in the southwest side of the belt. These volcano-sedimentary sequences are divided into Tuchengzi Formation, Zhangjiakou Formation, Yixian Formation and Jiufotang Formation re- spectively. They are characterized by southeastward migration as a result of the increasing down-dip slip displacement along the major extensional fault toward the southeast of the belt. The provenance area of the Jiufotang Formation north to it experienced southwestward thrusting during and after its later sedimentation. The thrusting in this stage resulted in the formation of an asymmetric footwall syncline with vergence to SW in the Jiufotang Formation in the NE side of the basin. Finally a dextral strike-slip deformation occurred along the NW tectonic belt. The striking tectono-geomorphological features and present seismic activities along this belt indicate that it has been being active since Cenozoic era and is still in the active state at present. This northwest extending tectonic belt was following the same direction and location as the existing fault systems within the basement as revealed by former geological and geophysical studies. So it is reasonable to infer the Mesozoic deformation along this belt to be a result of reactivation of the basement structures in a favorable tectonic stress field. The reactivation of basement struc- tures might be taken as one of the mechanisms of intraplate deformation and orogeny.

关键词： Yanshan Orogenic Belt, northwest extending tectonic complex, thrust system, geochronology.

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Effect and mechanism of stresses on rock permeability at different scales

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Science china Earth Sciences 2006年第7期49卷 714-723页

作者： YIN Shangxian1 & WANG Shangxu2.1. Safety Engineering College, North china Institute of Science and Technology, Yanjiao, beijing 101601, china 2. key laboratory of Geophysics Exploration, china University of Petroleum, beijing 100083. china Safety Engineering College North China Institute of Science and Technology Yanjiao Beijing China key laboratory of Geophysics Exploration China University of Petroleum Beijing China

The effect of geo-stress fields on macroscopic hydro-geological conditions or micro-cosmic permeability of water-bearing media should follow some laws or principles. Cases study and tests show that: (1) At macro-geologic large scale, deformed and crashed rocks which were induced by geo-stress fields changing provided space for groundwater storage and flow. Groundwater adjusts water-bearing space and dilatants fractures by flowing and press transferring. Coupling of liquid and solid can be implemented for rocks and groundwater. Although tectonic fields witness several times of change and build-up in geological time, stress fields forming regional tectonic framework are coherent with seepage fields, orientation of the maximum horizontal stress demonstrates main seepage direc-tions. (2. At macro-geologic middle scale, zones of stresses changing sharply, quite low stresses, stress or shear concentration can be used to show locations and types of main fractures, zones of geo-stresses changing equably can be acted as normal base media zones of tri-porosity media. (3) At micro-geologic small scale, tri-porosity media include fractured rocks, porous rocks and capillary rocks. Investigations indicate that porosity or permeability is functions of effective stresses, and po-rosity or permeability changing rules of porous rocks with variation of effective stresses can be de-scribed as the index model, the model of power exponent functions is suitable for those of fractured rocks, the model of the second power parabola for capillary rocks. The porosity and permeability loss in fractured rocks, which are greater than that in porous rocks, are shown by calculation of effective compressive coefficient and closing pressure in cracks. The calculations can also explain the mecha-nism why porosity changes are always larger than permeability changes. It is proved by the thick wall cylinder theory that the second power parabola relation between porosity or permeability loss and effective

关键词： geo-stress fields, seepage fields, tri-porosity media, effective stresses, permeability, porosity,scale.

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Petrogenesis of Songshugou dunite body in the Qinling orogenic belt, Central china: Constraints from geochemistry and melt inclusions

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Science china Earth Sciences 2005年第8期48卷 1146-1157页

作者： SU Li1,2. SONG Shuguang3 & ZHOU Dingwu1 1. key laboratory of Continental Dynamics of the Ministry of Education, Department of Geology, Northwestern University, Xi’an 710069, {2. 2. The Geological Lab Center, {2. University of Geosciences (beijing), beijing 100083. china 3. key laboratory of Orogenic Belts of the Ministry of Education, Department of Geology, Peking University, beijing 100871, {2. key laboratory of Continental Dynamics of the Ministry of Education Department of Geology Northwestern University Xi’an China The Geological Lab Center China University of Geosciences (Beijing)Beijing China key laboratory of Orogenic Belts of the Ministry of Education Department of Geology Peking University Beijing China

The Songshugou dunite body, which occupies an area of about 2. km2. is the largest ultramafic massif in the eastern Qinling orogenic belt, Central china. The major compo-nent of this body is dunitic rocks including mylonitic dunite and coarse-grained dunite; they oc-cupy about 95 vol% of the total body. Petrography, mineral composition, major and trace ele-ments and primitive melt inclusions have been investigated in this paper; all revealed that this dunite body is the product of melt-rock interaction by porous percolation flow. In comparison with dunite sills or veins in harzburgite from the basal part of Oman ophiolite, this dunite body is characterized by lower contents of Al2.3, CaO and HREE but higher content of highly incom-patible elements and Zr and Hf. The LREE enriched patterns and primitive mantle normalized spidergrams of trace elements are also different from the Oman dunite. Combining with melt in-clusions observed in olivines, we conclude that this dunite body is the product of large- scale porous percolation flow of high-MgO melts within depleted mantle peridotites. The high-MgO magma, in essence, was most probably produced at the hot head of an upwelling mantle plume. The occurrence of the Songshugou dunite body is closely associated with the activity of mantle super-plume in Neo-Proterozoic era in the Yangtze Craton.

关键词： Songshugou dunite body, geochemistry, melt inclusion, mantle plume, Qinling orogenic belt.

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A Creep Equation Based on Thermal Activation

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 44-46页

作者： Jiyue Sun Guoliang Chen (State key laboratory for Advanced Metals and Materials, University of Science and Technology {2., beijing 100083. china) State key laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

The creep equation proposed in so called θ projection concept is developed in the concept of thermal activation of creep. The measured creep curves of A2.6 alloy are fitted by the equation. The activation energy in theequation is evaluated, and creep rupture lives are predicted. The results are confirmed by creep tests of up to 13years.

关键词： creep creep curve equation creep rupture life A2.6 superalloy

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The refined theory of transversely isotropic piezoelectric rectangular beams

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 473-486页

作者： GAO Yang1 & WANG Minzhong2.1. College of Science, china Agricultural University, beijing 100083. china 2. State {2. laboratory for Turbulence and Complex Systems and Department of Mechanics and Engi- neering Science, Peking University, beijing 100871, china College of Science China Agricultural University Beijing China State key laboratory for Turbulence and Complex Systems and Department of Mechanics and Engineering Science Peking University Beijing China

The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.

关键词： rectangular beams, the refined theory, piezoelectric, transversely isotropic.

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The refined theory of deep rectangular beams based on general solutions of elasticity

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Science china(Physics,Mechanics & Astronomy) 2006年第3期49卷 291-303页

The problem of deducing one-dimensional theory from two-dimensional the- ory for a homogeneous isotropic beam is investigated. Based on elasticity theory, the re- fined theory of rectangular beams is derived by using Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. Based on the refined beam theory, the exact equations for the beam without transverse surface loadings are derived and consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beam under transverse loadings are derived directly from the refined beam theory and are almost the same as the governing equations of Timoshenko beam theory. In two ex- amples, it is shown that the new theory provides better results than Levinson’s beam the- ory when compared with those obtained from the linear theory of elasticity.

关键词： deep rectangular beams,the refined theory,Papkovich-Neuber solution,Lur'e method,governing equation

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MEAM Potential with Angular Dependence for TiAl

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Rare Metals 2001年第1期20卷 13-17页

作者： Xiaodong Ni, Xitao Wang, Guoliang Chen (Physics Department, University of Science and Technology beijing, beijing 100083. china State {2. laboratory for Advanced Metals and Materials, University of Science and Technology beijing, beijing 100083. china) 北京科技大学新金属材料国家重点实验室北京 100083 北京科技大学北京 100083

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces. By fitted to the lattice constants, the cohesive energy, the APE (anti-phase boundary) energy, and the vacancy formation energy of TiAl, an accurate MEAM potential is obtained for the TiAl system with L10 structure. The calculation results of the properties of TiAl are in good agreement with experiments and the results of first principle (F.P.) calculations.

关键词： embedded atom method TiAl alloy angular dependence potential intermetallics

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