检索结果-南通市图书馆

Metallogenic characteristics of epithermal gold deposits in Tianshan, Xinjiang, china

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第S2期44卷 138-139页

作者： FENG Jianzhong~1, FU Shuixing~2. WU Dewen~3 and YANG Zian~3 1. Department of geology, Peking University, beijing 100871,{2. 2. beijing institute of geology for Mineral Resources, beijing 100012.{2. 3. Center of Remote Sensing for geology, CNNC, beijing 101601,{2. Department of geology Peking University Beijing 100871 China beijing institute of {2. for Mineral Resources Beijing 100012 China Center of Remote Sensing for geology CNNC Beijing 101601 China

TIANSHAN in southern Xinjiang belongs to the Paleozoic island arc system in which volcanic rocks are extensively distributed. A series of epithermal gold deposits such as the Axi, Xitan, Cuiling andShuangfengshan gold deposits have been discovered. 1 Geological settings of epithermal gold deposits in Tianshan, southern Xinjiang Tianshan in southern Xinjiang belongs to the Paleozoic island arc system. To its north is the Kazakhstan plate, and to its north is the Tarim plate. From west to east, the tectonic units are characterizedby Yili island arc, southern Tianshan arc-basin, Jiaoluotage island arc and Xingxingxia island arc. TheEW-trending Tianshan ore belt is controlled by Kanggurtag geosuture. In its west part, it is controlled byShenglidaban geosuture. The linear structure is NNW-trending; from north to south, the faults

关键词： metallogenic characteristics gold deposits Tianshan Xinjiang.

SHRIMP zircon U-Pb age and Nd isotopic study on the Nyainqêntanglha Group in Tibet

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第9期48卷 1377-1386页

作者： HU Daogong1, WU Zhenhan1, JIANG Wan1, SHI Yuruo2. YE Peisheng1 & LIU Qisheng1 1. institute of Geomechanics, Chinese Academy of Geological Sciences, beijing 100081,{2. 2. institute of geology, Chinese Academy of Geological Sciences, beijing SHRIMP Centre, beijing 100037,{2. institute of Geomechanics Chinese Academy of Geological Sciences Beijing China institute of geology Chinese Academy of Geological Sciences Beijing SHRIMP Centre Beijing China

The Nyainqêntanglha Group is traditionally viewed as the oldest metamorphic basement in the Lhasa block, but its formation age and tectonic setting remain debate. Zircons extracted from the metamorphic sequence of volcanics and intrusions of the Nyainqêntanglha Group, 10 km west of Nam Co in northern Lhasa block, have been investigated by cathodolu- minescence (CL), backscattered (BSE) and dated by ion microprobe (SHRIMP). We conclude that the U-Pb age of 787±9 Ma of zircons from the trondhjemite imposes a constraint on maxi- mum protolith age, and minimum formation age of the Nyainqêntanglha Group is constrained by U-Pb age of 748±8 Ma of zircons from the granite. The formation age of the Nyainqêntanglha Group is consistent with sedimentary age of Greater Himalayan rocks, showing that they devel- oped coevally in an arc-basin tectonic setting of Neoproterozoic active continental margin along the northern margin of the India shield. The inherited zircons from the tholetiite and granite give older 2.7Pb/2.6Pb ages from 947 to 1766 Ma. The positive εNd( t ) value indicates that the mafic rocks were derived from the depleted mantle, but contaminated by the older continental crustal material. Integrated Nd model age and U-Pb age data provide excellent evidence for the exis- tence of Mesoproterozoic basement in the Lhasa block during Neoproterozoic time.

关键词： Nyainqêntanglha Group, SHRIMP dating, Nd isotope, Neoproterozoic, Tibet.

Seismic wave propagating in Kelvin-Voigt homogeneous visco-elastic media

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第2期49卷 147-153页

作者： YUAN Chunfang1, PENG Suping1, ZHANG Zhongjie2.& LIU Zhenkuan3 1. china University of Mining & Technology, beijing 100083, china 2. institute of Geophysics, Chinese Academy of Sciences, beijing 100101, china 3. Exploration and Development Research institute of Daqing Oilfield, Daqing 163712. china china University of Mining & Technology Beijing China institute of Geophysics Chinese Academy of Sciences Beijing China Exploration and Development Research institute of Daqing Oilfield Daqing China

This paper studies, under a small disturbance, the responses of seismic transient wave in the visco-elastic media and the analytic solution of the corresponding third-order partial differential equation. A plane wave solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differ-ential equation with a pulse source is obtained. By the principle of pulse stacking of particle vibration, the result is extended to the solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differential equation with any source. The velocities of seismic wave propagating and the attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are discussed. The velocities of seismic wave propagating and the coefficient of attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are derived, expressed as functions of density of the media, elastic modulus and visco-elastic coefficient. These results can be applied in inversing lithology parameters in geophysical prospecting.

关键词： Kelvin-Voigt visco-elastic velocity attenuation seismic wave.

Wave tectono-sedimentary processes in Tarim basin

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第11期48卷 1949-1959页

作者： JIN Zhijun1,2. ZHANG Yiwei1 & CHEN Shuping1 1. Key Laboratory for Hydrocarbon Accumulation, Ministry of Education, china University of Petroleum, beijing 102.49, china 2. Exploration and Production Research institute, china Petroleum & Chemical Corporation, beijing 100083, china Key Laboratory for Hydrocarbon Accumulation Ministry of Education China University of Petroleum Beijing China Exploration and Production Research institute China Petroleum & Chemical Corporation Beijing China

Based on the unconformities, the formation times of structures, and geological wave filtering applied to basin fills of typical wells around the Manjiaer area in the Tarim basin, the wave tectono-sedimentary processes in the Tarim Basin are discussed. The results of geological wave filtering of basin fills of typical wells show that, in time domain, the evolution of the Tarim basin was controlled by various wave processes with the periods of 740±Ma, 2.0±Ma, 100±Ma and 30±Ma. The analyses of basin fills, basin subsidence and unconformities show that the trends of the sedimentary facies belts, depocenters, and centers of subsidence migrated and interchanged periodically with periods of 2.0±Ma. These show the propagation of wave movements in space domain. The wave evolution of the Tarim basin is of significance to understanding the formation of the oil and gas reservoirs in the basin.

关键词： Tarim basin, tectonics, sedimentation, crustal undation, wave evolution

PROSPECTING FOR THE HIDDEN ACTIVE FAULT BY MEASURING THE 2.8p0 AND 2.0p0

在线全文

学校读者我要写书评

暂无评论

地震地质 1992年第1期 17-22页

作者： Zhang Yusong Hu Yutai Li Jianhua(institute of geology,State {2. bureau,beijing 10002.)

A method of prospecting for the concealed active fault by simultaneous measuring both 2.8Po and 2.0Po is *** is a radioactive *** concentration of radon near the fault can be determined from the activities of its daughters 2.8Po and *** the fault,there is a good passage for gases,and the radioative gas from crustal depths can be easy to get to the *** a result,the level of the radioactivity there is quite high,but low at both sides far from *** observational points where the *** of 2.8Po and 2.0Po is much higher than their background values can be regarded as the position of the hidden fault we want to seek.A number of observations at the known faults and hidden active ones indicate that seeking hidden active faults on certain conditions of their outcrops by measuring 2.8Po and 2.0Po is an effective,efficient-and hopeful way.

关键词： 2.8Po 2.0Po Daughter 2.2.n Activity Hidden activy fault Hebei

Effects of the grain size distribution on the temperature-dependent magnetic susceptibility of magnetite nanoparticles

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第7期53卷 1071-1078页

作者： ZHAO XiangYu1,2.& LIU QingSong1 1 Paleomagnetism and Geochronology Laboratory (SKL-LE), institute of geology and Geophysics, Chinese Academy of Sciences,{2., china 2.Graduate University of Chinese Academy of Sciences, beijing 100049, china Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

Magnetite is an important magnetic remanence carrier in natural samples and therefore is of great interest in paleo-, rock-, and environmental magnetism. The magnetic properties of magnetite depend on many factors, e.g., concentration and grain size distribution (GSD). In this study, we theoretically investigated the temperature-dependent susceptibility (TDS) of magnetite nanoparticles with a lognormal GSD. Results show that the TDS is affected highly by the GSD mainly in three aspects. Firstly, the unblocking process becomes smoother with the increase of distribution width, characterizing as a wider Hopkinson peak on the TDS curve. Secondly, the blocking temperature increases with the increase of the median diameter or/and the distribution width. Thirdly, the maximum susceptibility decreases with the increase of distribution width, and has a logarithmic function relation with the standard deviation of the distribution. As a case study, this model was further applied to the thermal products of the Chinese loess/paleosol samples to determine the granulometry of newly-formed magnetite upon heating based on TDS curves. The results demonstrate the fidelity and feasibility of this method to determine the GSD of nano-sized magnetic particles.

关键词： Néel theory temperature dependence of susceptibility grain size distribution

Mass Extinction——A Fundamental Indicator for Major Natural Divisions of Geological History

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1988年第1期1卷 1-12页

作者： Xu Daoyi Zhang Qinwen Sun Yiyin institute of geology, State {2. bureau, beijing institute of geology, Chinese Academy of Geological Sciences, beijing institute of geology, Academia Sinica, beijing institute of geology State Seismological Bureau Beijing China

In the Phanerozoic, there are three major geological boundaries: Precambrian/***/Triassic and Cretaceous/Tertiary. Studies of these boundaries in china and over the world stronglysuggest that they have the following similar features: mass extinctions of many taxa, positive anomalies ofplatinum-group metals, and abrupt changes of stable isotopes (δ13C). It is quite probable that these were theconsequences of some rare catastrophic events of extraterrestrial origin. Hence, the three above-mentionedmass extinction events may be regarded as key indicators for the division of the geological history of thePhanerozoic.

关键词： Mass Extinction A Fundamental Indicator for Major Natural Divisions of Geological History

Discovery of immune related factors in Fenneropenaeus chinensis by annotation of ESTs

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第1期14卷 48-55页

作者： SHEN Yaoqing 1,2. , XIANG Jianhai 1*, WANG Bing 1,2. , LI Fuhua 1 and TONG Wei 3(1. Experimental Marine Biology Laboratory, institute of Oceanology, Chinese Academy of Sciences, Qingdao 2.6071,china 2. Graduate School of the Chinese Academy of Sciences, {2. 100039, china 3. Genomics & Bioinformatics institute, Chinese Academy of Sciences, {2. 101300, china) Chinese Acad Sci Inst Oceanol Expt Marine Biol Lab Qingdao 266071 Peoples R China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China Chinese Acad Sci Geonom & Bioinformat Inst Beijing 101300 Peoples R China

A total of 10446 expressed sequence tags (ESTs) are obtained by a large scale sequencing of a cDNA library from cephalothorax of adult Fenneropenaeus chinensis . An EST analysis platform was built up based on local computers and bioinformatic techniques were used to annotate these ESTs in order to promptly find possible functional genes, especially for immune related factors. About 4% of the ESTs show similarity to the coding sequences of such factors, including lectin, serine protease, serpin, lysozyme, etc. These ESTs provide a partial profile of the immune system in F. chinensis and useful information for further study on these genes.

关键词： Fenneropenaeus chinensis bioinformatics ESTs immune factors

Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1,2.and Luo Zhexian2.1. institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 10002.,{2. 2. Nanjing University of Information Sciences & Technology, Nanjing 2.0044,{2.) institute of Atmospheric Physics Chinese Acad. of Sci. Beijing 100029 China Nanjing University of Information Sciences and Technology Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 12.0 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation