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Zircon SHRIMP geochronology and geochemistry of TTG rocks in Sushui Complex from Zhongtiao Mountains with its geological implications

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Progress in Natural Science:Materials International 2006年第5期16卷 492-500页

作者： TIAN Wei, LIU Shuwen, LIU Chaohui, YU Shengqiang, LI Qiugen and WANG Yueran (Key Laboratory of Orogenic Belt and Crustal Evolution, MOE, school of earth and space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belt and Crustal Evolution MOE School of Earth and Space Sciences Peking University Beijing 100871 China

The tonalite-trondhjemite-granodiorite (TTG) rocks in Sushui Complex of Zhongtiao Block can be divided into two series according to their zircon U-Pb ages and geochemical characteristics: one is subduction-related (SR) and the other collision-related (CR) . The SR TTG rocks, together with other Late Archean island arc magmatism, were developed as a result of oceanic subduction between the Eastern and Western blocks in Late Archean; while the CR TTG rocks formed in a thickened crustal environment, which was responding to the collision between the Eastern and Western blocks in Paleoproterozoic. All these features support a model that the Zhongtiao Block is a part of the Trans-North china Orogen in the middle of North china Craton.

关键词： Sushui Complex Zhongtiao Block Trans-North china Orogen zircon U-Pb geochronology trace element simulation.

The attenuation anisotropy of mudstones and shales in subsurface formations

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Science china earth sciences 2005年第11期48卷 1882-1890页

作者： SHI Ge1 & DENG Jixin1,2 1. The Key Labratory of Orogenic Belts and Crustal Evolution, school of earth and space sciences, peking university, beijing 100871, china 2. Geophysical Prospecting Key Lab (CNPC), university of Petroleum, beijing 102249, china The Key Labratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing China Geophysical Prospecting Key Lab (CNPC) University of Petroleum Beijing China

We have measured the relationships in the laboratorial condition between the at-tenuation in three samples of mudstones and shales as well as two samples of layered sand-stones and the alteration in direction, confining pressure and pore fluid. The relative contributions of different attenuation mechanisms are also discussed. Studies show that the attenuation in dry and saturated samples is strongly related to pressure and direction. The attenuation coefficient of P-wave propagating parallel to bedding (PH ) is less than that of P-wave propagating vertical to bedding (PV ), while the attenuation coefficient of S-wave both propagating and vibrating parallel to bedding (SH ) and that of S-wave propagating vertical to bedding while vibrating parallel to bedding (SV1) are less than that of S-wave propagating parallel to bedding while vibrating verti-cal to bedding (SV ). Under oil saturated conditions, the Biot flow attenuation acts as the domi-nant mechanism for waves propagating parallel to bedding, while the frame anelastic attenuation and squirt flow attenuation seem to play important roles in condition of propagation vertical to bedding.

关键词： mudstone, shale, attenuation, anisotropy, attenuation mechanism

Two new species of Vestrogothia (Phosphatocopina, Crustacea) of Orsten-type preservation from the Upper Cambrian in western Hunan, South china

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Science china earth sciences 2009年第6期52卷 784-796页

作者： ZHANG HuaQiao1,2 & DONG XiPing1,2 1 school of earth and space sciences,peking university,beijing 100871,china 2 State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of sciences,Nanjing 210008,china school of earth and space sciences Peking University Beijing China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

Although fossils of Orsten-type preservation represented by Skaracarida and Phosphatocopina were first reported from the Middle and Upper Cambrian in western Hunan, South china in 2005, diversified phosphatocopine species have never been appropriately described and elucidated in terms of their evolutionary relationships. Here, we described two new species of Phosphatocopina, Vestrogothia anterispinata sp. nov. and V. bispinata sp. nov. The evolutionary relationship among all the valid species of Phosphatocopina is discussed and the phylogeny of Phosphatocopina is reestablished using cladistic analysis. Accordingly, phosphatocopines primitively evolved along two lineages: one evolved towards the emergence of lobes; the other evolved towards the emergence of dorsal spines. Respectively, lobes originated independently three times, and dorsal spines originated only once. With regard to the dorsal rims, interdorsum originated first, whereas dorsal furrow originated independently twice on the basis of interdorsum. Probably Hesslandona may represent a polyphyletic group, whereas Vestrogothia a monophyletic group.

关键词： fossils of Orsten-type preservation Vestrogothia Phosphatocopina Crustacea evolution phylogeny Cambrian Hunan

Source time-function as discriminant using empirical Green's function

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Science china earth sciences 2005年第12期48卷 2118-2122页

作者： HE Yongfeng1,2 & CHEN Xiaofei1 1. Department of Geophysics, school of earth & space sciences, peking university, beijing 100871, china 2. North-West Institute of Nuclear Technology, Xi’an 710024, china Department of Geophysics School of Earth & Space Sciences Peking University Beijing China North-West Institute of Nuclear Technology Xi’an China

The source mechanism of underground nuclear explosions is remarkably different from that of earthquakes in both spatial radiation pattern and source time-function (STF). Small underground nuclear explosions can be used as empirical Green’s functions (EGF) to isolate the source-time spectrum of a large suspected earthquake occurred in a Nuclear Test Site (target area) by the spectral division method. As this study shows, with high-quality data, the quotient spectrum can be transformed to the time domain, yielding the apparent far-field source-time function of the large suspected event. The relative source time-function (RSTF) of a nuclear ex-plosion is usually a simple pulse with a duration of about 1 s., while an earthquake’s is more complicated with a series of pulses and a longer duration. The RSTF can be used as a nice dis-criminant to distinguish the nature earthquakes from underground nuclear explosions in target areas.

关键词： target-area, empirical Green's function, RSTF.

Ultramafic xenoliths in Mesozoic diorite in west Shandong Province

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Science china earth sciences 2004年第6期47卷 489-499页

作者： CHEN Lihui1,2 & ZHOU Xinhua2 1.The Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,china and school of earth and space sciences,peking university,beijing 100871,china 2.Institute of Geology and Geophysics,Chinese Academy of sciences,beijing 100029,china Correspondence should be addressed to Chen Lihui(email: lihui_chen@***) The Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education China and School of Earth and Space Science Peking University Beijing China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

Ultramafic xenoliths are common in Tietonggou intrusion, Laiwu, Shandong Prov-ince. Peridotite xenoliths develop two-stage metasomatism popularly: (i) The early metasoma-tism is characterized by intergranular clinopyroxene and phlogopite; (ii) The later metasomatism is characterized by orthopyroxene veins with a few plagioclases and amphiboles. These ul-tramafic xenoliths are thought to be mostly from the crust-mantle transitional zone on the basis of their combination, mineral chemistry, equilibrium temperature, and metasomatic characteristics. Major elements, rare earth elements, and Sr-Nd isotopic composition of the ultramafic xenoliths indicate that there is a petrogenetic relationship between the silica-enriched xenoliths and their host diorites. We propose that such silica enrichment might be an indicator of melt-rock interac-tions in the Mesozoic lithosphere beneath western Shandong.

关键词： ultramafic xenoliths, crust-mantle transitional zone,metasomatism, Tietonggou intrusion, Laiwu.

Petrogenesis of Paleoproterozoic Luyashan charnockitic rocks in Shanxi Province: Constraints from Geochemistry and Nd isotope

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Progress in Natural Science:Materials International 2006年第2期16卷 183-191页

作者： LIU Chaohui, LIU Shuwen, LI Qiugen, WANG Yueran, DANG Qingning, GU Libing, YANG Bin and ZHAO Fengsan (Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education school of earth and space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University Beijing 100871 China

Luyashan charnockite pluton mainly consists of monzonite, adamellite, charnockite and syenogranite, which are characterized by the enrichment of TiO2, P2O5, K2O, Zr, Nb, Y, Pb, La, Ce, Ba and a higher K2O/Na2O and depletion of MgO, CaO, Mg#, Th, U and lower Sr/Ba and Rb/Ba. The negative correlations between Zr, Nb, Ce and SiO2 are distinct from I-type granites. Iso-topically Luyashan charnockite plutons are relatively uniform in Nd isotope, displaying initial εNd(t) (-5.93 to -6.97) and Nd depleted mantle model ages (2.67 Ga to 2.78Ga). These features indicate that Luyashan charnockitic magma derived from pre-existing late Archean crustal sources and the partial melting of mafic granulites probably under exceptionally high temperature with CO2-rich fluid. The garnet is a main residual phase during the partial melting. The original dry charnockitic magma experienced crystal fractionation of pyroxene, plagioclase, apatite and ilmenite during early crystallization. The geochemical evidence suggests that the Luyashan charnockitic magma was probably generated in the post-collision thermal relaxation and uplift tectonic setting after the main collision ( - 1850 Ma) between the Eastern and Western continental blocks.

关键词： Luyashan charnockite geochemistry Sm-Nd isotopes petrogenesis Paleoproterozoic.

The internal structure of Early Cambrian fossil embryo Olivooides revealed in the light of Synchrotron X-ray Tomographic Microscopy

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Chinese Science Bulletin 2008年第24期53卷 3860-3865页

作者： CHEN Fang1,2 & DONG XiPing1,2 1 school of earth and space sciences,peking university,beijing 100871,china 2 Laboratory of Paleontology and Stratigraphy,Nanjing Institute of Geology and Paleontology,Chinese Academy of sciences,Nan-jing 210008,china school of earth and space sciences Peking University Beijing China Laboratory of Paleontology and Stratigraphy Nanjing Institute of Geology and Paleontology Chinese Academy of Sciences Nanjing China

Countless fossil embryo Olivooides and the hatched larvae,juveniles and adults(the latter two kinds are Punctatus) are recovered by means of acid maceration from the fine-crystalline to medium-crystalline phosphatic limestone and phosphatic micrite of Early Cambrian Kuanchuanpu Formation at the Shizhonggou section,near Kuanchuanpu Village,Ningqiang County,Shaanxi Province,*** the technique of Synchrotron X-ray Tomographic Microscopy,the 3D internal structure of Olivooides and Punctatus is *** morphological and statistic analyses are also given to the stellae structure of Olivooides and Punctatus,which indicates that this structure is a result of adaptive evolution to a lifestyle of fast-attaching after hatching,probably with the function of mucilage *** internal structure of Punctatus is described and *** ovum-like structure,a common internal feature of Punctatus,is considered as the taphonomic structure,rather than eggs or other biological *** structure is thought to be formed after the burial of the animal and before or during the *** original internal structure of Punctatus is assumed to be tabulae-filled,with soft body grown on them.

关键词：同步加速器 X射线显微镜寒武系化石动物区系内部结构

Numerical study of the auroral particle transport in the polar upper atmosphere

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Science china(Technological sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3 1 school of Electronic Information, Wuhan university, Wuhan 430079, china 2 Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, Wuhan 430079, china 3 school of earth and space sciences, peking university, beijing 100871, china school of Electronic Information Wuhan University Wuhan China Key Laboratory of Geospace Environment and Geodesy Ministry of Education of PRC Wuhan China school of earth and space sciences Peking University Beijing China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

An Early Cretaceous Avialian Bird, Shenzhouraptor sinensis from Western Liaoning, china

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Acta Geologica Sinica(English Edition) 2003年第1期77卷 21-27页

作者： Ji Qiang, Ji Shu’an, You Hailu, Zhang Jianping,Zhang Hongbin, Zhang Nanjun, Yuan Chongxi and Ji XinxinDepartment of earth sciences, Nanjing university, Nanjing, Jiangsu 100093Institute of Geology, Chinese Academy of Geological sciences, beijing 100037 school of earth and space sciences, peking university, beijing 100871china university of Geosciences, beijing 100083 china Dinosaur Park of Changzhou, Changzhou, Jiangsu 213002 Nanjing Univ Dept Earth Sci Nanjing 100093 Jiangsu Peoples R China Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China peking Univ Sch Earth & Space Sci Beijing 100871 Peoples R China china Univ Geosci Beijing 100083 Peoples R China china Dinosaur Pk Changzhou Changzhou 213002 Jiangsu Peoples R China

This paper describes an avialian bird from the Early Cretaceous JiufotangFormation in Yixian county, western Liaoning china, which is named as Shenzhouraptor sinensis by Jiet al. on July 15, 2002. Shenzhouraptor sinensis is characterized by no teeth in its mouth, theforelimbs longer than the hindlimbs, a long tail with more than 23 caudal vertebrae, U-shapedwishbone, and remiges longer than the total length of ulna and manus. It is certain that the newavialian bird is really capable of powerful flight, representing a missing link between theropoddinosaurs and birds.

关键词： Avialian birds Early Cretaceous Jiufotang Formation western Liaoning china