检索结果-南通市图书馆

Chinese Science Bulletin 1999年第5期44卷 398-411页

作者： LU Guxian, CHEN Jing, LIU Ruixun and LI Xiaobo institute of Geomechanics , beijing 100081, china Electron Microscopy Laboratory, Peking University, beijing 100871, china Department of Geology, Peking University, beijing 100871, china institute of geological information , beijing 100037, china institute of Geomechanics Beijing China Electron Microscopy Laboratory Peking University Beijing China Department of Geology Peking University Beijing China institute of Gelogical information Beijing China

The knowledge that hydrostatic pressure is equal to the gravity value of the overlying rocks in studying a dynamic state of certain underground site is argued. It is suggested that the stress field T in the crust is a combination or superposition of total hydrostatic pressure P with differential stress σ,and the total hydrostatic pressure P at any point in the crust comprises two parts: one is spherical stress tensor PG caused by the gravity, and the other is spherical stress tensor Ps caused by tectonic stress; therefore P could not be attributed to the gravity of overlying rocks only. The results obtained by a finite-element simulation indicate that the tectono-original additional hydrostatic pressures Ps decrease gradually from the compressive zone （pcS） to the shear zone (PSHs)and to the tensile zone （PTs）, i.e.Pcs>PsHs>PTs in the same depth. On the basis of the above-mentioned research, the method of measurement and calculation of metallogenetic depth corrected by Ps is

关键词： formation depth tectonic additional hydrostatic pressure Dabie UHPM zone coesite-bearing eclogite expansion-cracking texture tectonic physicochemistry.

Depth of coesite-bearing eclogite formation, Dabie UHPM zone, china, based on structure stress correction

在线全文

学校读者我要写书评

暂无评论

Depth of coesite-bearing eclogite formation, Dabie UHPM zone...

The possible contribution of a mantle-derived fluid to the Ningwu porphyry iron deposits—Evidence from carbon and strontium isotopes of apatites

地壳深部压力状态与地质作用学术研讨会

作者： Lü Guxian, Chen Jing, Ding Tiping, Li Xiaobo, Wang Fangzheng and Liu Ruixun institute of Geomechanics, beijing, 100081, china Electron Microscopy Laboratory, Peking University, beijing, 100871, china Open Research Laboratory of Isotope Geology, Chinese Academy of geological Sciences, beijing 100037, china institute of geological information, beijing, 100037, china china University of Geosciences, Wuhan, Hubei, 430074, china Department of Geology, Peking University, beijing, 100871, china

＜正＞ Plastic deformation of garnet in coesite-bearing eclogite, quartz eclogite and garnet amphibolite of the ultra-high pressure metamorphic（UHPM） complex in Yingshan County, Dabie Mountains, has been studied by transmission electron microscopy （TEM）. Garnets have undergone ductile deformation under eclogite and amphibolite facies conditions. Garnet microstructures vary greatly with the dislocation density of the garnet being lower in coesite-bearing eclogite is than that in garnel *** generated by strong tectonic movement were an important component of the total pressure causing the formation of eclogite in the Dabie UHPM zone. The three-dimensional tectonic principal stresses and additional tectonic stress-induced hydrostatic pressure [Ps=-（σ1+σ2+σ3）/3] are reconstructed according to the differential stress and strain ratio （a） of garnet in minor coesite-bearing eclogite of Yingshan county. Then the gravity-induced hydrostatic pressure （PG） is calculated through P minus PS, where P is estimated to be 2.8 GPa based on the quartz-coesite geobarmeter. Therefore, the thickness of the rock column overlying the coesite-bearing eclogite in Yingshan county is determined to be ≥2.09-32.11 km. this estimation is significantly different from the previous estimation of ≥100km obtained solely by considering the weight/specific weight ratio （W/SW）.It gives also a proper explanation to the puzzle that no tracer of addition of mantle-derived material has been found in the Dabie UHPM zone during the process of UHPM, although a number of researches claim that this process was taking place at depth of the mantle （≥100 km） . It is concluded that attention should be paid to the additional tectonic stress-induced hydrostatic pressure in the study of UHPM zones.

关键词： Dabie UHPM zone formation depth additional tectonic stress-induced hydrostatic pressure coesite-bearing eclogite tectonic physicochemistry plastic deformation garnet

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第2期18卷 167-172页

作者： Jinjie Yu ,Jingwen Mao,Changqing Zhang institute of Mineral Resources,Chinese Academy of geological Science,beijing 100037,china institute of Mineral Resources Chinese Academy of Geological Science Beijing 100037 China

Apatite is a characteristic mineral for the iron deposits in the Ningwu region. Apatite shows a range of d13CPDB values from à9.6& to à0.6&,and most of them with the d13CPDB values distributed in a range of mantle carbon (i.e.,à2& to à9&),except for samples T-06-1 and J-06-3. Apatites in the Ningwu porphyry iron deposits yield a narrow variation range of 87Sr/86Sr values from 0.706326 to 0.707577,similar to those of the volcanic and subvolcanic rocks and higher than that of a typical mantle-derived magmatic apatite (i.e.,about 0.7040),indicating that formation of the apatites was involved with crust material contamination. d13CPDB and 87Sr/86Sr values of the apatite indicate a possible contribution of mantle-derived fluid and material to formation of the Ningwu porphyry iron deposits,supported by regional geology,regional gravities and geochemistry of the volcanic and subvolcanic rocks in the Ningwu region.

关键词： Apatite 87Sr/86Sr ratios Fluid inclusion d13C Mantle fluid and material

Mineralization episode of porphyry copper deposits in the Jinshajiang-Red River mineralization belt: Re-Os dating

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 2005年第2期48卷 192-198页

作者： WANG Denghong, QU Wenjun, LI Zhiwei, YIN Hanlong4 & CHEN Yuchuan institute of Mineral Resources, Chinese Academy of geological Sciences, beijing 100037, china National Center of Rock and Mineral Analysis, Chinese Academy of geological Sciences, beijing 100037, china Resource Assessment Center of Yunnan, Kunming 650011, china institute of Geology and Geophysics, Chinese Academy of Sciences, beijing 100101, china Chinese Academy of geological Sciences, beijing 100037, china 1. institute of Mineral Resources Chinese Academy of Geological Sciences 100037 Beijing China 2. National Center of Rock and Mineral Analysis Chinese Academy of Geological Sciences 100037 Beijing China 3. Resource Assessment Center of Yunnan 650011 Kunming China 4. institute of Geology and Geophysics Chinese Academy of Sciences 100101 Beijing China 5. Chinese Academy of geological Sciences 100037 Beijing China

Re-Os isotopic dating for the molybdenites from the porphyry copper deposits of the Jinshajiang-Red River mineralization belt in Yunnan Province yields isochron ages of 33.9±1.1 Ma for the Machangqing deposit and 34.4±0.5 Ma for the Tongchang deposit. This result shows that both the Machangqing and the Tongchang porphyry Cu-Mo deposits from two different ore-fields formed simultaneously. This new data and the published Re-Os model ages of molybdenite (35.4 Ma, 35.9 Ma, 36.2 Ma) of the Yulong porphyry copper deposit in Tibet, which is located in the same Jinshajiang-Red River mineralization belt as the Machangqing deposit and the Tongchang deposit, suggest that these three Cenozoic porphyry copper deposits in the Jinshajiang-Red River mineralization belt were contemporary for their mineralization episode. That is to say, even their present locality is far away and nearly iso-distantly distributed, these three porphyry Cu(Mo) deposits belong to the same mineralization episode at the end of Eocene.

关键词： Re-Os isotopic dating, porphyry Cu deposits, Cenozoic, mineralization episode.

Discovery of the budding phosphatized globular fossils from the Neoproterozoic Doushantuo Formation at Weng'an, Guizhou Province, china

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第10期16卷 1079-1083页

作者： LIU Pengju , YIN Chongyu and TANG Feng (institute of Geology, Chinese Academy of geological Sciences, beijing 100037, china) [a]institute of Geology Chinese Academy of Geological Sciences Beijing China

There is much debate on biological affinities of the phosphatized globular fossils from the Neoproterozoic Doushantuo phosphorites at Weng’an, Guizhou Province. Here we report for the first time the budding structures of some of these globular fossils, which have previously been interpreted as the resting eggs and early cleavage embryos of metazoans. The budding structures are similar to the germinating tubes of the spore and zygote of living algae, suggesting that some globular fossils from the Doushantuo phosphorites bear affinity with algae. The present new information indicated various biological affinity of the phosphatized globular fossils from the Doushantuo phosphorites.

关键词： Neoproterozoic Donshantuo Formation globular fossil budding structure algae resting eggs embryos.

Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands, Malaysia, and Their Implications

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1999年第1期73卷 120-122页

作者： Chen Tingyu institute of Geology 26 Baiwanzhuang Road,Chinese Academy of geological Sciences, beijing 100037,china institute of Geology 26 Baiwanzhuang Road Chinese Academy of Geological Sciences Beijing 100037 China

The Ninth Regional Congress on Geology, Mineral andEnergy Resources of Southeast Asia was held in KualaLumpur of Malaysia in August of 1998. After the Con-gress, the author participated in the geological fieldexcursion and investigation in the Langkawi Islands,and noted that the Carboniferous-Permian rocks con-tain megaclasts of metamorphic and pegmatitic rocks,which indicate the existence of pre-Carboniferousmetamorphism and magmatism. The observation resultsare as follows:

关键词： Malaysia and Their Implications Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands

The upper mantle structure of the Tibetan Plateau and its implication for the continent-continent collision

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第8期48卷 1158-1164页

作者： WU Qingju1, ZENG Rongsheng1 & ZHAO Wenjin2 1. institute of Geophysics, china Earthquake Administration, beijing 100081, china 2. institute of Geology, china Academy of geological Sciences, beijing 100037, china 1. institute of Geophysics China Earthquake Administration 100081 Beijing China 2. institute of Geology China Academy of Geological Sciences 100037 Beijing China

The upper mantle structures of Himalayas-Tibet have been obtained from the mi-gration of receiver functions of the teleseismic events recorded by INDEPTH-III. The result of migration imaging shows a dipping interface subducting northward from the depth of 100 km to the 410-km discontinuity underneath southern Tibet. It indicates that the lithospheric mantle of the Indian continent had been detached from the crust and deeply subducted to the upper mantle of Eurasia during the Indo-Eurasian collision. This kind of continent-continent collision process is fundamentally different from the oceanic collision.

关键词： Tibetan Plateau, receiver function, upper mantle structures, Indo-Eurasian collision, dipping interface.

U-Pb dating of zircon from the bed parallel anatectic granitic intrusion in the Baoban group in Hainan Island and the tectonic implication

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第12期48卷 2092-2103页

作者： DING Shijiang1, HU Jianmin2, SONG Biao3,4, CHEN Mulun1, XIE Shengzhou1 & FAN Yuan1 1. geological Surveying institute of Hainan, Haikou 570206, china 2. institute of Geomechanics, Chinese Academy of geological Sciences, beijing 100081, china 3. beijing Center of SHRIMP, beijing 100037, china 4. institute of Geology, Chinese Academy of geological Sciences, beijing 100037, china 1. geological Surveying institute of Hainan 570206 Haikou China 2. institute of Geomechanics Chinese Academy of Geological Sciences 100081 Beijing China 3. beijing Center of SHRIMP 100037 Beijing China 4. institute of Geology Chinese Academy of Geological Sciences 100037 Beijing China

The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the beijing Ion-probe Center, acquire 206Pb/238U ages of 368±3.5 Ma (of granite, 95% confidence level, MSDW=1.23) and 362.9±6.1 Ma (of gneiss, 95% confidence level, MSDW = 2.04) respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.

关键词： Hainan Island, Devonian period, anatectic granite, zircon SHRIMP U-Pb dating.

^(40)Ar/^(39)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第9期47卷 794-803页

作者： ZHANG Yueqiao1, CHEN Wen2, 3 & YANG Nong1 1. institute of Geomechanics, Chinese Academy of geological Sciences, beijing 100081, china 2. institute of Geology, Chinese Academy of geological Sciences, beijing 100037, china 3. institute of Geology and Geophysics, Chinese Academy of Sciences, beijing 100029, china institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 350℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.

关键词： Xianshuihe fault zone, Zheduoshan granitic massif, sinistral shear deformation, 40Ar/39Ar dating, late Cenozoic.

Underplating in the middle-lower Yangtze Valley and model of geodynamic evolution:Constraints from geophysical data

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第7期48卷 985-999页

作者： Lü Qingtian, HOU Zengqian, YANG Zhusen & SHI Danian institute of Mineral Resources,Chinese Academy of geological Sciences,beijing 100037,china institute of Mineral Resources Chinese Academy of Geoloqical Sciences Beijina 100037 China

The lower crust and Moho are the most active boundary layers in the process of continental evolution, in which marks left by tectonic and magmatic activities during the process are preserved. The evolutionary process of the continental lithosphere may be reconstructed by exploring the structures of the lower crust and Moho. According to a study of the deep seismic reflection data obtained from the middle-lower Yangtze Valley, the authors find bright layered reflections ubiquitous in the lower crust and think that the bright reflections are caused by un-derplating of basic or ultrabasic magmas, which might be related to delamination of the lithosphere. On the basis of an integrated analysis of the geophysical and geological data of the region, the authors propose a model for geodynamic evolution of the middle-lower Yangtze Valley. This model suggests that the middle-lower Yangtze Valley had undergone such geodynamic processes as collision-compression, delamination-extension and underplating-melting since the end of the Permian, finally forming the gigantic middle-lower Yangtze Valley metallogenic belt.

关键词： lower crust deep seismic reflection underplating tectonic evolution.