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Geochemical Properties and StratigraphicalCorrelation of Frasnian-Famennian TransitionalStrata in Wuzhishan Section

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Journal of china university of geosciences 2002年第1期13卷 48-52页

作者： Wang Chaoyong Xia WenchenFaculty of earth sciences ,{2. , wuhan 43.074 Faculty of earth sciences China University of Geosciences Wuhan 430074

The qualities of petrology and paleobiology in Wuzhishan Section are studied. Several geo-chemical anomalies are recognized, such as: high rare earth element content, high pyrite content and Ni anomalies. It could be correlated with Nandong Section in Xiangzhou County and the F/F boundary could be determined according to Ni anomalies. The results of the study indicate that the geochemical anomaly plays an important role in stratigraphic correlation in non-fossil stratum.

关键词： Frasnian-Famennian geochemical anomaly rare earth element stratigraphic correla-tion.

A new iguanodontid (Jin-zhousaurus yangi *** ***.) from the Yixian Formation of western Liaoning,china

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Chinese Science Bulletin 2001年第19期46卷 1669-1672页

作者： WANG Xiaolin & XU Xing1. Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of sciences, Beijing 10004.,{2. 2. College of earth sciences and Resources,{2. university of Geo-sciences, Beijing 100083,{2. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing China College of earth sciences and Resources China University of Geosciences Beijing China

A new iguanodontid, Jinzhousaurus yangi gen. et sp. nov., is erected based on the cranial and dental morphology of a specimen from the Yixian Formation of western Liaoning. Although a few primitive characteristics remain, Jinzhousaurus yangi display a number of characteristics similar to those seen in derived iguanodontids. Other interesting characteristics include the absence of antorbital fenestra and the frontal excluded from the participation in orbit, which are closer to the condition in hadrosaurids. The unusual combination of the characteristics provides important data for assessing morphological evolution toward hadrosaurs. The new discovery also represents the first reported large-sized dinosaur from Jehol fauna in western Liaoning, and increases the diversity of this famous fauna. Furthermore, the discovery of a derived iguanodontid from the Yixian Formation provides further evidence supporting a Cretaceous age of the Jehol fauna, which is consistent with an isotopic age.

关键词： Western Liaoning Lower Cretaceous Yixian Formation Jehol Biota Iguanodontid

Synthesis of todorokite by refluxing process and its primary characteristics

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Science china earth {2. 2004年第8期47卷 760-768页

作者： FENG Xionghan1, LIU Fan1, TAN Wenfeng1, LIU Xiangwen2.& HU Hongqing1 1. College of Resources and Environment, Huazhong Agricultural university, wuhan {2.0070, china 2. Testing Center, china university of geosciences,{{2., china 1. College of Resources and Environment Huazhong Agricultural University 430070 Wuhan China 2. Testing Center China University of Geosciences 430074 Wuhan China

Single phase and well-crystallined todorokite were synthesized by heating and refluxing process from birnessite as a precursor. The average chemical composition of the synthesized todorokites by refluxing for 8 h and for 2.0}h was Mg0.19MnO2.11(H2.)1.15 and in0.17-MnO2.10(H2.)0.88, respectively. The crystallinity of the todorokite increased and no other phase was produced with increasing refluxing period. The synthesized todorokites have the same morphologies and the similar structural characteristics with the natural todorokites and hydro-thermally synthesized samples. The chemical compositions of the synthetic tordorokites by refluxing process are close to those of todorokites synthesized by hydrothermal process, except a higher average oxidation state of Mn for the former.

关键词： todorokite,birnessite,manganese oxide,refluxing,hydrothermal,synthesis.

Pathways of birnessite formation in alkali medium

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Science china earth {2. 2005年第9期48卷 1438-1451页

作者： FENG Xionghan1, TAN Wenfeng1, LIU Fan1, HUANG Qiaoyun1 & LIU Xiangwen2.1. College of Resources and Environment, Huazhong Agricultural university, wuhan {2.0070, china 2. Testing Center, china university of geosciences,{{2., china 1. College of Resources and Environment Huazhong Agricultural University 430070 Wuhan China 2. Testing Center China University of Geosciences 430074 Wuhan China

Birnessite is a common weathering and oxidation product of manganese-bearing rocks. An O2.oxidation procedure of Mn(OH)2.in the alkali medium has been used to synthesize birnessite. Fast and powder X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), energy dispersed X-ray analysis (EDAX), infrared spectroscopy (IR) techniques and chemical composition analysis, Eh-pH equilibrium diagram approaches were employed to investigate the reaction process and pathways of birnessite formation. Results showed that the process of the birnessite formation could be divided into four stages: (1) forma- tion stage for hausmannite and feitknechtite, (2. stage of transformation of hausmannite and feitknechtite to buserite, (3) buserite crystal growing stage, and (4. stage of conversion of buser- ite into birnessite. Mn(OH)2.was mainly present as amorphous state only for a short initial time of oxidation reaction. In the oxidation process, buserite formed following two pathways by recrys- tallization after dissolution of the intermediates, and the transformations of the minerals de- pended on the Eh determined by the dissolved O2.concentration on their surfaces. The results are fundamental in further exploration on the mechanism of birnessite formation in the alkali medium. A great practical significance would also be expected with respect to the areas of mate- rial sciences.

关键词： birnessite, pathway of formation, reaction process, Eh-pH diagram, hausmannite, feitknechtite.

Depositional Model and Tectonic Evolution of Tertiary Transform-Extensional Basins in Northeast china: Case Study on Yitong and Damintun Grabens

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Journal of earth Science 1997年第1期16卷 62-67页

作者：  Xie Xinong Huang Yanqiu Faculty of earth Resources, china university of geosciences,{2.Lu ZongshengFaculty of earth {4., china university of geosciences,{2.

? The formation and evolution of the Tertiary transformextensional basins in Northeast china are controlled by extensional and strikeslidding combinational processes because the giant strikeslip fault system, TanchengLujiang fault, cut through the basement or margin. Two kinds of structural styles have been identified in Northeast china: Yitong and Damintun styles. The former shows a clear asymmetry, in which sediments came mainly from two lateral sides and thick filling sediments were adjacent to the main strikeslip fault. The latter shows symmetry filling, in which sediments came from the long axial ends in addition to from two lateral sides. The tectonic evolution of Tertiary transformextensional basins in Northeast china underwent three stages: Eocene extensional, Oligocene transformextensional and Neogene transpressional stages.

关键词： transformextensional basin Tertiary Yitong graben Xialiaohe basin.

Magnetic Structure of Archean Kongling Group from Yangtze Craton,South china

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Journal of earth Science 1998年第2期17卷 52-59页

作者： Liu Qingsheng Department of Applied Geophysics, china university of geosciences, wuhan 43.074 Gao Shan Faculty of {2. sciences, china university of geosciences, wuhan 43.074 Xu Qidong Faculty of {2. Resources, china university of geosciences, W

Densities and various magnetic parameters (susceptibility, saturation magnetization, saturation isothermal remanent magnetization and intrinsic coercivity) were measured for 2. representative rock samples of different lithologies from the Archean Kongling amphibolite to granulite facies terrain of the Yangtze craton. Metasedimentary rocks and tonalitic trondhjemitic granodioritic granitic (TTGG) gneisses show that values of susceptibility κ and saturation isothermal remanent magnetization SIRM are higher than those of amphibolites and gabbros. The felsic gneisses have averages of κ =(1 163±375)×10 -6 SI, SIRM =(18.2.±8.38) A/m and R 1=0.083 3± 0.005 7 and the metasedimentary rocks κ =(1 2.6±82.)×10 -6 SI, SIRM =(2..70±10.91) A/m and R I=0.071 4.0.02. 2. In contrast, mafic rocks have average κ =(764.316)×10 -6 SI, SIRM = (10.4.±3.94.A/m and R 1=0.036±0.009 4. and are dominated by a mixed paramagnetic and ferrimagnetic behavior. Thermal magnetic analyses indicate that magnetite and maghemite of low coercivity are the major carriers of remanent magnetism in the metaclastic sedimentary rocks and TTGG gneisses. The amphibolite and gabbro contain minor amounts of magnetite and pyrrhotite. Magnetism of metaclastic sedimentary rocks and TTGG gneisses is highly heterogeneous; variation coefficients of κ and SIRM are as high as 67 % and 53 % for the former and 32.% and 4. % for the latter. Mineral compositions suggest that biotite may be responsible for the higher magnetism of the metasedimentary rocks. The highest variations in κ, SIRM and R I exhibited by metasedimentary rocks can also be interpreted by their largest absolute variations in biotite mass fraction relative to mafic rocks and felsic gneisses. The average ratio ( Q ) of natural remanent magnetization to induced magnetization of felsic gneisses and metasediments is 0.4. . Ratios ( REM ) of natural remanent to sat

关键词： magnetic structure amphibolite granulite facies Yangtze craton.

Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature

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Science china earth {2. 2005年第8期48卷 1120-1133页

作者： ZHOU Wenge1, XIE Hongsen1, LIU Yonggang1, ZHENG Xiaogang1, ZHAO Zhidan2.& ZHOU Hui3 1. Laboratory of Material in the earth’s Interior, Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002.{2. 2. Department of Geology, china university of geosciences, Beijing 100083,{2. 3. Department of Geology, Peking university, Beijing 100871,{2. 1. Laboratory of Material in the earth’s Interior Institute of Geochemistry Chinese Academy of Sciences 550002 Guiyang China 2. Department of Geology China University of Geosciences 100083 Beijing China 3. Department of Geology Peking University 100871 Beijing China

Two sets of dehydration-melting with a natural solid amphibolite, collected from North Himalayan structure zone, Tibet, have been carried out in multi-anvil apparatus at 2.0 GPa and 800―1000℃, for 12.2.0 h. One is keeping the pressure at 2.0 GPa and the annealing time of 12.h, changing the temperature (800―1000℃). The other is keeping the pressure at 2.0 GPa and temperature at 850℃, varying the annealing time (12.2.0 h). The products are inspected with microscope and electron probe. The results indicate that at 2.0 GPa, annealing time of 12.h, garnets, melts and clinopyroxenes occur in amphibolite gradually with increasing temperature and the chemical compositions of melt vary from tonalite to granodiorite, and then to tonalite. However, at 2.0 GPa and 850℃, with the annealing time increasing, the garnets, melts and cli-nopyroxenes also occur in amphibolite gradually and the chemical compositions of melt vary from tonalite to granodiorite. In both cases, melts interconnect with each other when the contents of melt are over the 5 vol.%. the viscosities of the melt produced in amphibolite at temperature higher than 850℃ are on a level with 104.Pa·s. The interconnected melt with such a viscosity may segregate from the source rock and form the magma over reasonable geological time. Therefore, it is believed that at the lower part of the overthickened crust, the tonlitic and grano-dioritic magma may be generated through the dehydration melting of amphibolite.

关键词： solid amphibolite, high pressure, high temperature, time, partial melting.

Griesbachian Cyclostratigraphy at MajiashanSection, Anhui Province, china

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Journal of china university of geosciences 2001年第1期12卷 22-26页

作者： Peng Yuanqiao Tong Jinnan Faculty of earth sciences,{2., wuhan 43.074 Gao Yongqun{2. Press, wuhan 43.074 Faculty of earth sciences China University of Geosciences china university of {2. Press

The Lower Triassic at Majiashan Section, deposited in the deep part of the Lower Yangtze carbonate ramp, is the only outcrop of the deep Lower Triassic preserved in the present Lower Yangtze region. Even so, the alternations of mudrock of mudrock and marl (or limestone) are still very distinct and recognizableable, though usually more or less condensed. The lithological and geochemical cycles at Majiashan Section are discussed in terms of the sedimentary characters and the contents of some elements analyzed at a 2.centimeter-interval with no hiatus of the Lower Triassic. The division resolution of the Griesbachian stratigraphy may increase to the scale of ten thousand years by the mudrock-marl (or limestone) bundles and the geochemical cycles. The analysis of the relationship between the sedimentary cycles/the geochemical cycles and the Milankovitch cycles may suggest the time limit and the sedimentary rates.

关键词： Majiashan Section Griesbachian sedimentary bundles geochemical characters Milankovitch cycles.

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 4.0079, china 2.Key Laboratory of Geospace Environment and Geodesy, Ministry of Education of PRC, wuhan 4.0079, china 3 School of earth and Space sciences, Peking university, Beijing 100871, china 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

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