检索结果-南通市图书馆

carbon isotope composition and its implications of Lower Cretaceous Aptian-Albian shallow water carbonates in the Cuoqin Basin, North Tibet

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第3期47卷 247-254页

作者： ZHU Jingquan1, LI Yongtie2. JIANG Maosheng1 & CHEN Daizhao1 1. institute of Geology and geophysics, Chinese Academy of Sciences, Beijing 10002., China 2. Research institute of Petroleum Exploration and Development, CNPC, Beijing 100083, China Chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China CNPC Res Inst Petr Explorat & Dev Beijing 100083 Peoples R China

The d 13C values of Lower Cretaceous Aptian-Albian platform-type carbonates in the Cuoqin Basin, North Tibet vary between 2.48 and 5.46. The mean value is 3.93. The values are not only provided with positive excursion, but also 1.17 higher than those of con-temporaneous pelagic carbonates which possess pretty high d 13C values. The origin is ap-proached. During the oceanic anoxic events, a great number of organisms were rapidly buried, causing the increase of the d 13C value of oceanic total dissolved carbon (TDC) and generally promoting the values of marine carbonates. After that, owing to the organisms undergoing dif-ferent isotopic fractionation in the paleo-ocean with stratified structure, d 13C values of shallow sea carbonate were obviously higher than those of pelagic carbonates.

关键词： shallow water carbonate, stable carbon isotope, paleooceanography, Aptian-Albian stage, Cuoqin Basin.

Crustal structure of Gondwana-and Yangtze-typed blocks:An example by wide-angle seismic profile from Menglian to Malong in western Yunnan

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 1828-1836页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3, LI Jiliang1, SUN Shanxue1 & WANG Xinzheng1 1. institute of Geology and geophysics, Chinese Academy of Sciences, Beijing 10002., China 2. institute of geophysics, Chinese Seismological Bureau, Beijing 100081, China 3. institute of Deposition Resource, Chinese Academy of Geological Sciences, Beijing 100037, China 1. institute of Geology and geophysics Chinese Academy of Sciences 100029 Beijing China 2. institute of geophysics Chinese Seismological Bureau 100081 Beijing China 3. institute of Deposition Resource Chinese Academy of Geological Sciences 100037 Beijing China

The wide-angle seismic profile between Menglian and Malong crosses the Baoshan block (Gondwana-typed), and Simao and southwestern Yangtze blocks (Yangtze-typed). By in-terpreting the wide-angle seismic data, we obtained the seismic crust/upper mantle structure of P-wave velocities together with the seismic reflections of these three blocks, Changning- Menglian and Mojiang suture zones among the mentioned three blocks. Our interpreting results demonstrate that the P-wave crustal velocity of Simao block is slower than that of Baoshan and southwestern Yangtze block and the crustal thickness gradually thickens from the Baoshan block, Simao to southwestern Yangtze block. Crustal reflection patterns of these three blocks have dis-tinct differences too. For the Gondwana-typed blocks, seismic reflections in the upper crust are well developed while in middle-lower crust they are very weak. The crustal reflections in the Yangtze block are very well developed. The crustal reflection patterns in Simao and southwest-ern Yangtze blocks are distinguishable. The average thickness of the crust in the studied area is about 40 km. And we make some discussions on the crustal thickening model of the three blocks in western Yunnan and tectonic setting of seismic developing and interaction of Gondwana and Yangtze blocks.

关键词： Gondwana blocks,Yangtze blocks,wide-angle profile,crustal structure,tectonic setting

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 {2., Chinese Academy of Sciences, Beijing 100101, China 3. Exploration and Development Research institute of Daqing Oilfield, Daqing 163712. China 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

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.

Si-and alkali-rich melt inclusions in minerals of mantle peridotites from eastern China:Implication for lithospheric evolution

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2006年第1期49卷 43-49页

作者： FAN Qicheng1, SUI Jianli2. XU Ping2. LI Ni1, SUN Qian1 & WANG Tuanhua1 1. institute of Geology, China Seismological Bureau, Beijing 10002., China 2. institute of Geology and {2., Chinese Academy of Sciences, Beijing 10002., China 1. institute of Geology China Seismological Bureau Beijing 100029 China 2. institute of Geology and geophysics Chinese Academy of Sciences Beijing 100029 China

Minerals of spinel- and garnet-facies mantle xenoliths entrained in Cenozoicbasalts from eastern China (North China, Northeastern China and Southeastern China coastal area)contains lots of melt inclusions. Studies on these melt inclusions show that the glass inclusionsare rich in SiO_2.(60%—68%) and alkalis (K_2.+Na_2. = 5%—11%, especially for K_2.) as well asvolatiles such as H_2. and CO_2.(2.—7%), which belong to dacites and andesites of the high-K calcicalkali series rocks with few shoshonites. High Al and ca diopside in melt inclusion is the productof melt crystallization at high temperature and pressure, rather than the product ofdevitrification. Results show that these K-rich (in general K_2. > 3%) intermediate-acidic silicatemelt inclusions have characteristics of continent without a genetical link to host basalts and theirphenocrystic minerals. Thus, these trapped melt inclusions represent melts of Mesozoic lithosphericmantle-crust interaction and imply that the continental lithospheric mantle beneath eastern Chinahad undergone fragmentation and recreation processes during the Mesozoic and Cenozoic periods. Thisresult undoubtly provides important implication for the evolution of sub-continental lithospherebeneath eastern China. We propose that these Si- and alkalis-rich melts should be responsible forthe mantle chemical heterogeneity underneath eastern China.

关键词： Si- and alkali-rich melt inclusion, mantle peridotite, lithospheric evolution, eastern China.

Virtual ChuanDian--A parallel numerical modeling of Sichuan-Yunnan regional strong earthquake activities: Model construction and parallel simulation

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第10期52卷 1585-1598页

作者： ZHANG Huai1, WU ZhongLiang1,2. ZHANG DongNing2. LIU Jie2. WANG Hui2. YAN ZhenZhen1,2.& SHI YaoLin11 Laboratory of Computational Geodynamics, Graduate university of Chinese Academy of Sciences, Beijing 100049, China 2.institute of {2., Chinese Earthquake Administration, Beijing 100081, China 1. Laboratory of Computational Geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China 2. institute of geophysics Chinese Earthquake Administration Beijing 100081 China

Reasonable use of mathematical modeling and numerical simulation of regional earthquake activities has attracted more and more attentions in realistic seismicity studies in recent years. The inherent nature of their attendant multi-scale properties, from either the temporal or the spatial direction, necessitates the use of the cutting-edge massive parallel data processing techniques. Our study here is focused on the model construction and numerical simulation of the regional stress evolution after large earthquake sequences along the fault zones in Sichuan and Yunnan areas, using large-scale parallel finite element approximations with tens of millions of unstructured meshes on the distributed systems. The objective of our study is to provide a state-of-the-art model and a large-scale numerical simulation platform, on which estimation of the risk of large earthquake triggering sequences can be carried out in a middle or long-term time scale with realistic data and constrains inputted from field observation and geological survey.

关键词： Sichuan-Yunan area seismic processing parallel simulation initial stress field

Sea level variations in the South China Sea inferred from satellite gravity,altimetry,and oceanographic data

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2012年第10期55卷 1696-1701页

作者： FENG Wei 1,2.ZHONG Min 1,3 & XU HouZe 1,3 1 State Key Laboratory of Geodesy and Earth’s Dynamics,institute of Geodesy and geophysics,Chinese Academy of Sciences,Wuhan 430077,China 2.Graduate {2. of Chinese Academy of Sciences,Beijing 100049,China 3 institute of geophysics,Huazhong {2. of Science and Technology,Wuhan 430074,China 1. State Key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Institute of Geophysics Huazhong University of Science and Technology Wuhan 430074 China

Sea level variations(SLVs) can be divided into two major components:the steric SLV and the mass-induced *** two components of SLV in the South China Sea(SCS) are studied by using satellite altimetry,GRACE(Gravity Recovery and Climate Experiment) satellite gravity,and oceanographic data on annual and inter-annual *** the annual timescale,the geographic distribution of mass-induced SLV's amplitude jointly estimated from altimetry and the ECCO(Estimation of the Circulation and Climate of the Ocean) model agrees very well with that from *** observes obvious seasonal mass-induced SLV in the SCS with annual amplitude of 2.7±0.4 cm,which is consistent with the annual amplitude of 2.7±0.3 cm estimated from the steric-corrected *** the inter-annual timescales,the mean SLV in the SCS shows a large oscillation,which is mainly caused by the steric *** trend of mean SLV inferred from altimetry in the SCS is 5.5±0.7 mm/yr for the period of 1993-2.09,which is significantly higher than the global sea level rise rate of 3.3±0.4 mm/yr in the same *** is no obvious trend signal in the mass-induced SLV detected from GRACE that indicates the water exchange between the SCS and its adjacent seas and land is in balance within the study period.

关键词： altimetry GRACE ECCO the South China Sea sea level variation

The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3, LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4 1. institute of Geology and geophysics, Chinese Academy of Sciences, Beijing 10002., China 2. institute of geophysics, China Seismological Bureau, Beijing 100085, China 3. institute of Deposition Resource, Chinese Academy of Geosciences, Beijing 100037, China 4. School of Exploration and Information, China university of Geosciences, Beijing 100083, China 1. institute of Geology and geophysics Chinese Academy of Sciences 100029 Beijing China 2. institute of geophysics China Seismological Bureau 100085 Beijing China 3. institute of Deposition Resource Chinese Academy of Geosciences 100037 Beijing China 4. School of Exploration and Information China University of Geosciences 100083 Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, China. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 40 km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

Flooding 1990s along the Yangtze River, has it concern of global warming?

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2001年第1期11卷 43-52页

作者： GONG Dao-yi1, ZHU Jin-hong2. WANG Shao-wu2.(1. Key Laboratory of Environmental Change and Natural Disaster, institute of Resources Science, Beijing Normal university, Beijing 100875, China 2. Department of {2., Peking university, Beijing 100871, Key Laboratory of Environmental Change and Natural Disaster Institute of Resources Science Beijing Normal University Beijing China Department of geophysics Peking University Beijing China

There were a series of severe floods along the middle to lower reaches of the Yangtze River (Changjiang River) in China during the 1990s. The extensive summer (June, July and August) precipitation is mostly responsible for the flooding. The summer rainfall in the 1980s and the 1990s is much higher than that in the previous 3 decades. The means for 1990–1999 is +87.62.mm above normal, marked the 1990s the wettest decade since the 1950s. Six stations with a time span of 1880–1999 are selected to establish century-long rainfall series. This series also shows that the 1990s is the wettest decade during the last 12. years. In the wettest 12.years, four occurred in the 1990s (1991, 1996, 1998 and 1999). Both global and China’s temperature show there is a relative lower air temperature during the 1960–1970s, and a rapid warming in the 1980–1990s. Comparisons of rainfall between 1960–1979 and 1980–1999 show there are dramatic changes. In the cold period 1960–1979, the summer rainfall along the Yangtze River is 3.8 % to 4.7 % below the normal, during the warm period 1980–1999, over 8.4 % to 18.2.% of summer rainfall occurs. Over the whole eastern China, the summer rainfall shows opposite spatial patterns from the 1960–1970s to 1980–1990s. The consistent trend toward more rainfall with global warming is also presented by the greenhouse scenario modeling. A millennial Drought/flood Index for the middle to lower reaches of the Yangtze River showed that although the surplus summer rainfall in the 1990s is the severest during the past 150 years, it is not outstanding in the context of past millennium. Power spectra of the Drought/flood Index show significant interdecadal periods at 33.3 and 11.8 years. Thus, both the natural interdecadal variations and the global warming may play important roles in the frequent floods witnessed during the last two decades.

关键词： summer rainfall Yangtze River global warming interdecadal variation

Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan,Northwest China:Evidence from sandstone detrital and geochemical records

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 1387-1402页

作者： LI Zhong1, GUO Hong2. WANG Daoxuan3 & LIN Wei1 1. institute of Geology and geophysics, Chinese Academy of Sciences, Beijing 10002., China 2. Tarim Oilfield Branch, CNPC, Korla 841000, China 3. Hefei {2. of Industry, Tunxilu 193, Hefei 2.0009, China 1. institute of Geology and geophysics Chinese Academy of Sciences 100029 Beijing Chin 2. Tarim Oilfield Branch CNPC 841000 Korla China 3. Hefei university of Industry Tunxilu 193 230009 Hefei Chin

Similar to compositional evolution of sandstone modes and detrital heavy minerals from different profiles in the Kuqa Depression, Northwest China, major element analysis of whole sandstones from the same profiles shows four discontinuous depositional interfaces or periods, respectively corresponding to Lower Triassic\Middle Triassic, Upper Jurassic\Lower Cretaceous, Lower Cretaceous\Paleogene and Miocene\Pliocene, and indicates five-phase evolution during Mesozoic-Cenozoic: (1) From the first to fifth phase, a depositional suite changes from maroon and coarse clastic, through grey-dark grey and fine, red and coarse, red-mottled, interlayered by gypsum, to brown and coarse clastic assemblages, accompanying detrital component evolution in unstable-stable-unstable-very unstable-very unstable assem- blages. It is indicated that carbonate and complex detritus gradually dominate in sandstones in post-Late Jurassic, with rapid reduction of compositional maturity. (2. For major element geo- chemical parameters of whole sandstones, caO and Fe2.O * 3+MgO contents show a change sequence in high-low-high-higher-highest values, with rapid increasing in post-Late Jurassic. (3) Contra some aggregative indicators for weathering indexes of sandstone detrital component, Al2.3/(caO+Na2.) and ln(Q/(L+CE)), show a change sequence in low-high-low-lower-lowest ratios, with rapid decreasing in post-Late Jurassic. It is found that sandstone samples of the first, second and later three phases may be distinguished from the A-CN-K and A-CNK-FM diagrams respectively. Therefore, in the Kuqa Depression-Tianshan, the most important discontinuous depositional interface recording paleotectonic and paleoclimatic transition occurred in Early Triassic\Middle Triassic and Late Jurassic\Early Cretaceous, respectively, and, however, tec- tonic differentiations of basin-range system finally result in distinct depositional systems but similar detrital weathering indexes across the Lower Cretaceous\Paleogene

关键词： Tianshan, Kuqa Depression, basin-range, depositional record, tectonic transition, Mesozoic-Cenozoic.