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Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor, NW China Since the Last Interglacial

Journal of Mountain Science 2004年第2期1卷 128-142页

作者： YANGTaibao YUYongtao LIJijun ANCongrong LIUJinfeng ZHANGJunyan KeyLaboratoryofWesternEnvironmentalChanges ChineseMinistryofEducationLanzhouUniversityLanzhou730000China departmentofGeography SchoolofGeosciencesNanjingNormalUniversityNanjing210097China Instituteofgeologyandgeophysics ChineseAcademyofSciencesBeo＇ing100029China

Paleomagnetic determinations on lithological profiles of two paralleled[( )-2.5(long )]drilling cores covering the past 13. kyr B.P., GT4. and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4.excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event ([(2..4.( )]kyr~[(2..8)( )]kyr), Laschamp Event ([(4.1}3.( )]kyr^4..5 kyr), Gaotai Event (82.8 kyr~[(72.4.2.( )]kyr) and the Blake Event (12..4.kyr^113.3.kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1-H6)[(. )-2.0( )]Here,[( )-2.0( )]we tentatively[( )-2.0( )]propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earths magnetic field shifted between a temporal normal and a negative period, the earths magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earths incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions.

关键词： Paleomagnetism geomagnetic excursion the Late Pleistocene arid Northwestern China

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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 geophysics, Chinese Academy of Sciences, Beijing 10002.{2. of geology, National Taiwan University, 2.5 Choushan Road, Taipei 106-17, Taiwan{2. of geology, Chinese Culture University, Hwa-kang, Yang-Ming-Shan, Taipei, Taiwan Institute of geology, Chinese Academy of Geological Sciences, Beijing 10003. Laboratory of Lithosphere Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 department of geology National Taiwan University 245 Choushan Road Taipei 106–17 Taiwan department of geology Chinese Culture University Hwa-kang Yang-Ming-Shan Taipei Taiwan Institute of geology Chinese Academy of Geological Sciences Beijing 100037 [?]5Zhou Yong Male born in 1968 graduated from Chengdu College of geology with a master's degree in 1991. From 1991 to 1995 he focused on ore deposit investigation. Since 1995 he has studied structural geology associated with the Qinghai-Tibet plateau. Tel: (010) 62008438.

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±0.2. Ma. The cumulative displacement from Muztag Ata to Muji is about 13. km.

关键词： Karakorum fault kinematics timing displacement

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P-SV快慢横波旋转分离公式研究

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天然气工业 2004年第12期24卷 44-47,186页

作者：唐建侯杨慧珠贺振华李亚林赵连锋清华大学工程力学系成都理工大学四川石油管理局地质调查处中国科学院地质与地球物理研究所

当P -SV横波穿越裂隙介质时会分裂成平行裂隙走向的快横波和垂直裂隙走向的慢横波 ,在某一时刻 ,快慢横波的偏振在空间具有不同的组合形式。文章研究了旋转分离公式与偏振方向和旋转方向的关系 ,推导出了快慢横波不同组合形式的分离公... 详细信息

当P -SV横波穿越裂隙介质时会分裂成平行裂隙走向的快横波和垂直裂隙走向的慢横波 ,在某一时刻 ,快慢横波的偏振在空间具有不同的组合形式。文章研究了旋转分离公式与偏振方向和旋转方向的关系 ,推导出了快慢横波不同组合形式的分离公式 ,其中顺时针旋转方向和逆时针旋转方向各有四个公式表述 ;同时还分析了公式的差异 ,并用实例进行了验证 ;提出了快慢横波传播过程中应用公式判别偏振情况的能量投影准则和快慢横波同相准则。通过实际资料的处理。

关键词：慢横波快横波裂隙介质偏振方向旋转方向资料能量公式时针实际

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Imaging of echo data of submarine sedimentary beds layer-by-layer with acoustic wave equation refraction correction method

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Chinese Journal of Acoustics 1995年第3期14卷 200-208页

作者： GENG Jianhua MA Zaitian and HUANG Haigui (department of Marins geology and {2., Tongji University, 2.0092.

Wide-angle echo data of submarine sedimentary beds are collected by a system composed of a seismic profiler and a hydrophone streamer towed behind the profiler. Usually the wide-angle echo data are processed with common-depth-point stack method to obtain the stacked section for gcological interpretation. When the acoustic velocity of the sedimentary layers has a lateral variation, the stacked section does not represent the real structure of sedimentary layers. Based on this stacked section, we would probably draw a false *** case of knowing the acoustic velocity of sedimentary beds, we may remove the distortions caused by acoustic velocity lateral variations from the stacked section with acoustie wave equation Kirchhoff integration which continues the wave fields in downgoing and upgoing directions respectively. Thus the accurate image of the structure of submarine sedimentary layers is obtained.

关键词： Imaging of echo data Submarine sedimentary bed Refraction correction

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Mineralogical and geochemical evidence for coupled bacterial uranium mineralization and hydrocarbon oxidation in the Shashagetai deposit,NW China

Mineralogical and geochemical evidence for coupled bacterial...

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中国科学院地质与地球物理研究所2.06学术年会

作者： Chunfang Cai~1,Hailiang Dong~2.Hongtao Li~1,Xinjian Xiao~3.Guanxi Ou~3. Chunming Zhang~4.1 Key Laboratory of Mineral Resources,Institute of geology and {4.,Chinese Academy of Sciences,P.O. Box 982.,Beitucheng Xilu No.19,Beijing 10002.,P.R.China 2.{2. of geology,Miami University,Oxford,OH 4.056,usa 3.Beijing Research Institute of Uranium geology,Beijing 10002.,P.R.of China 4.{2. of Geochemistry,Yangtze University,Jingzhou,Hubei 4.1}02.,PR China

Unusual mineral structures have recently been found in a sandstone-hosted roll-type uranium deposit in the Middle Jurassic Zhiluo Formation in the Shashagetai deposit,the northern Ordos basin,NW *** structures possess a chemical composition and crystal structure characteristic of mineral coffinite[(USiO)](OH)],which occurs as nanoparticles with size ranging from 5 to *** structures are interpreted to be fossilized microorganisms,based on mineralogical biosignatures including morphology,size,occurrence of biogenic coffinite as nano-crystals,and biological elements such as *** intimate intergrowth of coffinite with secondary pyrite of bacterial origin,as defined by lowδS values,and calcite cements with petroleum-derived carbon supports its biogenic *** inclusions in the host sandstone are characterized by abundant n-alkanes,slightly increased Pr/nC and Ph/nC ratios,significant amounts of demethylated hopanes and tricyclic terpanes,and the existence of unresolved complex *** characteristics are interpreted to be a result of mixing of an earlier,heavily degraded oil with a later charged fresh oil;subsequently the oils were slightly *** lines of evidence lead to the proposal that the reduction of sulfate and oxidization of petroleum are likely synchronous with reduction of hexavalent[U(Ⅵ)]to tetravalent[U(Ⅳ)]uranium by sulfate-reducing bacteria(SRB).The discovery of a natural association of microorganism-like structures,a uranium mineral,and biodegraded petroleum has implications for uranium biomineralization and fossil fuel exploration.

关键词： uranium deposit anaerobic petroleum oxidation sulfate-reducing bacteria nanoparticle microfossil sulfur isotopes

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Planetary wave oscillations in sporadic E layer occurrence at Wuhan

Planetary wave oscillations in sporadic E layer occurrence a...

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中国科学院地质与地球物理研究所2.08学术年会

作者： Xiaomin Zuo~(1,2.3.4. and Weixing Wan~1 1 Institute of geology and geophysics,Chinese Academy of Sciences,Beijing,10002.,China 2.Mathematics and Physics {2.,China University of Geosciences,4.1}074.China 3.Wuhan Institute of Physics and Mathematics,Chinese Academy of Sciences,China 4.Graduate School,Chinese Academy of Sciences,China

Quasi 6-day oscillations in E occurrence were observed to occur in relation with planetary wave activity at Wuhan,China(3..6°N,114.5°E).Wavelet analysis of E occurrence time series revealed that a strong 5- to 7-day oscillation was present during the period from about day 12. to 13. of *** same quasi 6-day planetary wave oscillation was also found to dominate the spectrum of concurrent wind data measured in the 80- to 100-km region by a meteor radar,in agreement with the E *** is also a great deal of similarity between the 5- to 7-day band-pass filtered waveforms of E occurrence and the wind *** estimating the wave phase changes with altitude,the quasi 6-day PW in the zonal wind was found to be in phase with the sporadic E layer critical frequency,fE,at about 115 km,close to the observed E *** quasi 6-day PW modulation was also present in the amplitude of the 12.h and 2.-h periodicities which existed in the fE time *** present results provide new evidence in favor of a planetary wave indirect role on E formation through the modulation of tides,which in line with previous studies by Haldoupis and Pancheva(2.02.,and Pancheva et al.(2.03..

关键词： Sporadic E layers planetary waves atmospheric tides PW modulation of tides

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New Light Shed on the Late Devonian Frasnian-Famennian （F/F） Biotic Crisis from δ13.carb, δ13.org and 87Sr/86Sr Isotopic Systematics

New Light Shed on the Late Devonian Frasnian-Famennian （F/F...

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中国矿物岩石地球化学学会第十届学术年会

作者： CHEN Dai-zhao, QING Hai-ruo ,LIA Ren-weiInstitute of geology and geophysics, Chinese Academy of Sciences, Beijing 10002., China {2. of geology, University of Regina, Regina SK, Canada S4. OA2

＜正＞ A severe biotic crisis occurred during the Late Devonian Frasnian-Famennian （F/F） transition （±3.7 Myr）. Here we present δ13.arb, δ13.orb and 87Sr/86Sr i sotopic systematics, from identical samples of two sections across F/F boundary in South China, which directly demonstrate large and frequent climatic fluctuations （-2.0 ka） from warming to cooling during the F/F transition. These climate fluctuations are interpreted to have been induced initially by increased volcanic outgassing, and subsequent enhanced chemical weathe-

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EXPERIMENTAL STUDY OF FRICTION FACTOR FOR GROUNDWATER FLOW IN A SINGLE ROUGH FRACTURE

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Journal of Hydrodynamics 2009年第6期21卷 820-825页

作者： CHEN Zhou QIAN Jia-zhong LUO Shao-he ZHAN Hong-bin School of Resources and Environmental Engineering Hefei University of Technology Hefei 230009 China department of Resources and Environment Henan Polytechnic University Jiaozuo 454010 China department of geology and {2. Texas A and M University College Station TX 77843-3115 USA

To study the relationships between the friction factor f and the flow type in a single rough fracture, the formulae of f for both unconfined and confined flows are deduced based on previous studies. The relationships between f and the Reynolds number （Re） for different relative roughnesses are investigated experimentally. The Moody-type diagram, based on the deduced formula of f, is also plotted and the hydraulic characteristics of the flow in a rough fracture are analyzed. Results show that the Moody-type diagram of the experiment has a similar distribution to that of the conventional Moody diagram. It is found that the value of f in the experiment is much smaller than that of the conventional Moody diagram and turbulent flow appears easier for rough fractures, which can be explained by the separation phenomenon in boundary layers. The critical Re ranging from 650 to 700 in rough fractures is concluded based on the experimental results. It also can be concluded that the friction factor f is related not only with the Re and the relative roughness but also with the absolute roughness.

关键词： friction factor rough fracture Moody diagram critical Reynolds number ( Re ) boundary layer

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Anisotropy of magnetic susceptibility of Hannuoba basalt,northern China:Constraints on the vent position of the lava sequences

Anisotropy of magnetic susceptibility of Hannuoba basalt,nor...

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中国科学院地质与地球物理研究所2.03.术年会

作者： Rixiang Zhu and Caidong Shi Institute of geology and geophysics,Chinese Academy of Sciences,Beijing,China Qingsong Liu Institute for Rock Magnetism and {2. of geology and geophysics,University of Minnesota,Minneapolis, Minnesota,usa

Anisotropy of magnetic susceptibility(AMS) was determined for Hannuoba basaltic samples from 17 flows (2..4.0.7Ma) distributed in three sections(Jianshaba, Yuershan and Manjing) around Zhangbei,northern China. The results show normal‘flow’ fabrics with horizontal foliation *** typical ratios of the principal AMS axes are 1.01 for the magnetic lineation(L) and 1.02.for the foliation(F),*** hysteresis loop, isothermal remanence,thermomagnetic properties,and optical observations indicate that pseudo-single domain (PSD) low-titanium magnetite particles dominate the low-field susceptibility of *** the AMS of the magma at this area is believed to be originated from the lineation of the low-Titanium magnetite particles driven by the lava flow. Since the K trends coincide well with the observed flow directions,the intersection of the mean K trends from: these three sites perfectly defines the previously known vent position of the lava sequences.

关键词： 1518 Geomagnetism and Paleomagnetism:Magnetic fabrics and anisotropy 1519 Geomagnetism and Paleomagnetism:Magnetic mineralogy and petrology 9604.Information Related to Geologic Time:Cenozoic

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Microbialite of anoxic condition from Permian-Triassic transition in Guizhou,China

Microbialite of anoxic condition from Permian-Triassic trans...

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中国科学院地质与地球物理研究所2.07学术年会

作者： WU YaSheng~(1+),JIANG HongXia~1,YANG Wan~2.& FAN JiaSong~1 1 Institute of geology and geophysics,Chinese Academy of Sciences,Beijing 10002.,China 2.{2. of geology,Wichita State University,184. Fairmount,Wichita,KS 672.0,usa

Spherical microfossils are present in the Hindeodus parvus zone of the Lower Triassic in Ziyun, Guizhou *** generally range from 0.15 to 0.3. mm across,with micritic wall and filled by micro-sparry calcites,and are evenly scattered in micritic *** abundance makes the rock assigned to *** accompanied organisms include ostracods and algal mat,but no gastropods or *** of small(2. limestone with rich globular microfossils such as that described from the Nanpanjiang Basin in China by Lehrmann(1999),(3. dendroidal limestone such as that described from the vicinity of Chongqing by Kershaw et al.(1999),(4. spherical microbial limestone adapted to anoxic environments described from Ziyun,Guizhou reported in this paper,(5) limestone with cyanobacterial fossils such as that described by Wang et al.(2.05),and(6) *** these microbialites are not reefs in the proper sense, and the argument that Permian reef ecosystems extended into the Mesozoic is incorrect.

关键词： Microbialites reefs Permian-Triassic boundary mass extinction end-Permian

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