检索结果-南通市图书馆

Advances and Overview of the Study on Paleo-earthquake Events: A Review of Seismites

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2015年第5期89卷 1702-1706,I0009,I0010,1707-1746页

作者： HE Bizhu QIAO Xiufu State key laboratory of Continental tectonics and Dynamics Institute of GeologyChinese Academy of Geological Sciences

The distribution and formation mechanisms of typical identified seismites are analyzed based on various factors from plate tectonic positions, types of sedimentary basins and properties of seismogenic faults to focal ***, structural styles, reserved positions, activity times, formation mechanisms and dynamics of soft-sediment deformation structures triggered by seismic activity are systematically *** to the genetic types of seismites, we propose 5 categories, including liquefied deformation, thixotropic deformation, hydroplastic deformation, superimposed gravity driving deformation and brittle ***, based on the main genetic types, composition of sediments and deformation styles, we draw up 35 secondary *** determine paleo-seismic sequences in different times, activities of seismogenic faults, high-resolution tectonic events in one main tectonic movement and paleo-tectonic settings, and to understand the inducing mechanisms of paleo-earthquakes and ecologic environment evolution, researching on seismites are of great *** multiple approaches to identify the paleoearthquake records, simulating experiments on various soft-sediment deformation structures triggered by different magnitudes of shocking, dating precisely on paleo-seismic events, impacting on paleogeography and biological environment and on energy and resources domain are the frontiers of paleoseismic research.

关键词： soft-sediment deformation structure formation mechanism seismites classification paleo-seismicity history and frontier

Diamonds and Other Exotic Minerals Recovered from Peridotites of the Dangqiong Ophiolite, Western Yarlung-Zangbo Suture Zone, Tibet

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2016年第2期90卷 425-439页

作者： XIONG Fahui YANG Jingsui ROBINSON Paul T. XU Xiangzhen BA Dengzhu LI Yuan ZHANG Zhongming RONG He CARMA State Key Laboratory for Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences

Various combinations of diamond, moissanite, zircon, quartz, corundum, rutile, titanite, almandine garnet, kyanite, and andalusite have been recovered from the Dangqiong peridotites. More than 80 grains of diamond have been recovered, most of which are pale yellow to reddish-orange to colorless. The grains are all 100-200 μm in size and mostly anhedral, but with a range of morphologies including elongated, octahedral and subhedral varieties. Their identification was confirmed by a characteristic shift in the Raman spectra between 1325 cm^-1 and 1333 cm^-1, mostly at 1331.51 cm^-1 or 1326.96 cm^-1. Integration of the mineralogical, petrological and geochemical data for the Dongqiong peridotites suggests a multi-stage formation for this body and similar ophiolites in the Yarlung-Zangbo suture zone. Chromian spinel grains and perhaps small bodies of chromitite crystallized at various depths in the upper mantle, and encapsulated the UHP, highly reduced and crustal minerals. Some oceanic crustal slabs containing the chromian spinel and their inclusion were later trapped in suprasubduction zones（SSZ）, where they were modified by island arc tholeiitic and boninitic magmas, thus changing the chromian spinel compositions and depositing chromitite ores in melt channels.

关键词： diamond Multi-stage formation Dangqiong ophiolite Yarlung-Zangbo suture zone

Paleoearthquake Investigation along the Chenghai Fault Zone since~500 ka,Southeast Margin of the Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2021年第4期95卷 1332-1345页

作者： YANG Shuaibin QIAO Yansong WU Zhonghai ZHANG Xujiao QI Lin HE Zexin LIANG Ying Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China The key laboratory of active tectonics and Crustal Stability Assessment Beijing 100081China School of Geosciences and Resources China University of GeosciencesBeijing 100083China

The Chenghai fault zone is located in the Sichuan–Yunnan rhombus block,which is surrounded by the Honghe River,Xianshuihe–Xiaojiang,and Jinsha River fault *** a mid-continental active fault,it is one of the most important seismogenic fractures in the southeast margin of the Tibetan *** seismic study is an important supplement to the historical seismic record;therefore,identification of paleoearthquake events in this region is of great significance to reveal the pattern and mechanism of earthquake *** this study,detailed investigation has been carried out on the earthquake traces that formed in the Quaternary sediments in the Jinsha River section of the Chenghai fault zone,and samples for dating chronology testing were also *** paleoearthquake traces were discovered in the field,including earthquake fissions,dammed lake sediments and landslides,earthquake-generated rock falls,seismic faults,and sand liquefaction *** collected samples were tested using optically stimulated luminescence,electron-spin resonance,and U-series methods.A total of 68 chronological samples were dated,combined with the results of field investigations,and 10 large paleoearthquake events were discovered in this region since 500 ka,which are at approximately 450,400,345,300,250,190,155,105,75,and 25 *** tectonic activity periods that produced multiple paleoearthquake events were identified since 500 *** study identifies paleoearthquake events in longer scales,larger spaces,and more extensive sediments,which provides new perspectives and new ideas for paleoearthquake research.

关键词： paleoearthquake earthquake fission dammed lake earthquake-generated rock fall Chenghai fault zone

Early Jurassic Soft-Sediment Deformation Interpreted as Seismites in the Wuqia Pull-Apart Basin and the Strike-Slip Talas-Ferghana Fault, Xinjiang, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2013年第3期87卷 730-737页

作者： QIAO Xiufu GUO Xianpu State key laboratory of Continental tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences

The early Jurassic soft-sediment deformation occurring within lacustrine sandstone is distributed mainly in the Wuqia region of SW Tianshan Mountains, Xinjiang, western China. Triggered by earthquakes, such deformation was found to occur in three beds overlying the lower Jurassic Kangsu Formation. The main styles of deformation structures comprise load cast, ball-and- pillow, droplet, cusps, homogeneous layer, and liquefied unconformity. The deformation layers reflect a series of three strong earthquakes at the end of early Jurassic in the Wuqia region. The differences of deformation mechanisms undergone might represent the varying magnitudes of the earthquake events. During the early Jurassic, the Wuqia region was located in a pull-apart basin controlled by the significant Talas-Ferghana strike-slip fault in central Asia, which initiated the soft-sediment deformation induced by earthquakes. Our research suggests that the paleoseismic magnitudes could have ranged from Ms 6.5 to 7.

关键词： Early Jurassic seismicity load droplet liquefied unconformity Talas-Ferghana fault Xinjiang

Numerical Approach for Thermal History Modelling in Multi-Episodic Rifting Basins

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2014年第3期25卷 519-528页

作者： Bo Kang Xinong Xie Tao Cui key laboratory of tectonics and Petroleum Resources of Ministry of Education China University of Geosciences CSIRO Land and Water

Pre-existing models for thermal history modelling have shown deficiency in explicit algorithms to establish the quantitative relationship between maturity indices and thermal gradients in some sedimentary basins that experienced multi-episodic rifting evolution. In this study, a forward and inverse combination model（FICM） is proposed to estimate the vitrinite reflectance（Ro） and thermal gradients. The forward module is used to calculate Ro values. It couples the EASY%Ro model with burial history reconstruction with consideration of thermal gradient variations during basin evolution. The inverse module reconstructs histoical thermal gradients by calibrating cmputed Ro against measured Ro data. The time-temperature series is a necessary input for both forward and inverse modules. Sample density is a profound factor influencing the accuracy of modelling results. In order to obtain satisfying outputs, a sufficient sample density is required. Thermal gradients are assumed to vary linearly between two given samples. Modelling results of case studies indicate that the sensitivity of heating time to Ro evlution is differnt with thermal gradients depending on geolgoical setting. Three difffernt districts, which include the time-sensitive area, the temperature-sensitive area and the non-sensitive area, can be recognized on the the relationship map among Ro variations, heating time and geothermal gradients. This model can be applied to reconstruct the thermal history and maturation evolution in a basin that has undergone complex multi-episodic rifting.

关键词： thermal history maturity EASY%Ro burial history vitrinite reflectance.

Formation Mechanism and Numerical Model of Quartz in Fine-Grained Organic-Rich Shales: A Case Study of Wufeng and Longmaxi Formations in Western Hubei Province, South China

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2020年第2期31卷 354-367页

作者： Bao Zhang Detian Yan Hassan Jasmine Drawarh Xiangrong Yang Jin He Liwei Zhang key laboratory of tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan 430074China

The difference in quartz types in shales not only affects the porosity and permeability of the rocks,but also reflects the difference in the sedimentary *** established the formation mechanism and numerical model of quartz in shales of Wufeng and Longmaxi formations in the Wangjiawan Section,South China,based on thin-section studies using SEM(scanning electron microscope),SEM-CL(cathodoluminescence),XRD(X-ray diffraction)and geochemical *** are two types of quartz in the shales:detrital quartz and authigenic *** quartz is mostly silt-size,typically ranging from 10 to 60μm in size and subangular to angular monocrystal in shape,and brighter than authigenic quartz by CL intensity;authigenic quartz is present in two phases in shape:grain overgrowths and crystallite *** surfaces are *** grains are typically less than 10μm in size,euhedral or subhedral monocrystal in *** quartz can be subdivided into biogenic quartz and clay mineral transformed quartz according to the source of *** the numerical model,the content of detrital quartz is relatively consistent(20%);the content of biogenic quartz ranges from 40%to 70%,with a sharp fall(0–30%)in the Guanyinqiao *** the Katian,a lower anoxic and dense water column make the dissolution of biogenic silica well *** quartz is the major contributor to the *** the early Hirnantian interval,due to the drop of sea level and the oxygenation of seafloor,the sediment is mainly composed of clay transformed quartz and detrital *** the latest Hirnatian and Rhuddanian,rapid sea level rise and anoxic ocean enhance the preservation of the biogenic silica,thereby biogenic quartz re-emerges as the major contributors to the *** crystallite grains and grain overgrowths have filled in primary pore space and have decreased the interparticle porosity,however,as a rigid framework,they can suppress compac

关键词： brittle mineral quartz Wufeng and Longmaxi formations formation mechanism numerical simulation

Rhenium-osmium isotope constraints on the age and source of the platinum mineralization in the Lower Cambrian black rock series of Hunan-Guizhou provinces, China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2003年第9期46卷 919-927页

作者：李胜荣肖启云申俊峰孙丽刘波阎柏琨江永宏 key laboratory of Lithospheric tectonics Ministry of Education of China China University of Geosciences Beijing 100083 China

The shale at the bottom of the Lower Cambrian black series in South China is rich in nonferrous metals, noble metals, rare and dispersed elements and radioactive elements, known as polyelement-rich bed. In order to date and trace the source of the platinum group elements, 6 samples were collected from the Zhongnan region of Guizhou Province, and the Ganzi- ping-Sancha region of Hunan Province. The contents and isotopes of Re and Os were measured. Re and Os are positively correlated with each other and the correlation coefficient between 187Os/188Os and 187Re/188Os is 0.99856. On the 187Os/188Os-187Re/188Os diagram, 6 sample points are well-distributed along the (542±11) Ma fitting isochron in high coincidence and with 0.84±0.12 as the initial 187Os/188Os value. The result displays that the age value of the major mineralization of Re, Os and other platinum group elements is (542±11) Ma, which is identical with the stratigraphical age of the wall rocks; the polyelement beds in Hunan and Guizhou provinces bear high isochroneity; the differences of the forming times of different materials in the polyelement bed of the same area do not surpass the error limit permissible for Re-Os date fitting; there exists no distinct time interval between the formation of the diagenetic veinlets and that of the polyelement bed, or the Re-Os isotope composition has not been distinctly changed by the former process; basaltic crust might be the major source of Re, Os, other platinum group and trace elements in the Lower Cambrian polyelement bed of Hunan and Guizhou provinces.

关键词： bottom of Cambrian System, black rock series, Re-Os isotopes, dating, source of materials, Hunan and Guizhou provinces, China.

Intricate Fault Systems in Longmenshan Structural Belt's Northern End:Exploring Structural Evolution and Seismic Rupture Behavior in the Eastern Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2025年第1期36卷 250-265页

作者： Hanyu Huang Renqi Lu Dengfa He Jinliang Gao Weikang Zhang Lingyu Kang State key laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China State key laboratory of Oil and Gas Reservoir Geology and Exploitation Institute of Sedimentary GeologyChengdu University of TechnologyChengdu 610059China College of Energy Resources China University of GeosciencesBeijing 100083China PetroChina Research Institute of Petroleum Exploration and Development Beijing 100083China

The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface *** models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal *** integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural *** area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan *** mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural *** the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing ***,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse *** study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.

关键词： Longmenshan structural belt fault system structural evolution tectonics earthquakes focal mechanism

Numerical Simulation and Probabilistic Hazard Assessment of Tephra Fallout at Jinlongdingzi volcano,Longgang Volcanic Field in Jilin Province

在线全文

学校读者我要写书评

暂无评论

Earthquake Research in China 2013年第3期27卷 391-400页

作者： Yu Hongmei Xu Jiandong Wu Jianping Luan Peng Zhao Bo Institute of Geophysics China Earthquake Administration key laboratory of active tectonics and volcano Institute of GeologyCEA Chinese Academy of Land and Resource Economics

Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. According to the improved 2D diffusion model of Suzuki （ 1983）, we edited a tephra diffusion program that can run in the Windows system. Based on previous data, we simulated the diffusion scope of the Jinlongdingzi volcanic eruption, which is the latest eruption in the Longgang volcanic cluster. The simulated results are in good agreement with the results from measurement in situ, indicating that the model is reliable and the parameters used in the model are suitable. By using wind profiles of ten years, 7, 021 simulations under different wind profiles were carried out, and then probabilistic hazard maps of tephra fallout were constructed for tephra thickness thresholds, lcm and 0.5cm. This study can provide an important scientific basis for volcanic hazard analysis, risk mitigation plans and countermeasures in the Longgang volcanic area.

关键词： Tephra fallout Numerical simulation Hazard probability maps Jinlongdingzi volcano Longgang volcanic cluster