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The crustal Shortening and Reconstruction of the Main Terranes Through Mesozoic-Cenozoic in Qinghai-Tibet Plateau

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地学前缘 2009年第S1期16卷 270-271页

作者： Meifeng Shi~(1,2),Yalin Li~2,Ke Cao~2 1.Chengdu Institute of Geology and Mineral Resources,Chengdu 610082,China. 2.School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China

It is one of hot issues in Tibetan research that is to study the mode,process and kinetics of the crustal shortening during *** this paper, on the basis of systematic collection,analysis and research of the existing data and results from Himalayas,Lhasa and Qiangtang terranes,we conducted the balanced cross-section *** the north Qiangtang,the line-balanced cross-section

关键词： Qinghai-Tibet Plateau crustal shortening shortening value terrane

THE MAIN UPLIFT PROCESSES OF DEEP crustal ROCKS OF THE EARLY PROTEROZOIC OROGENIC BELT IN DAQINGSHAN AREA,INNER MONGOLIA

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Journal of Central South University 1996年第1期8卷 94-97页

作者： Yu Haifeng He Shaoxun(Department of Geology, Central South University of Technology,Changsha 410083, China) Department of Geology Central South University of Technology Changsha 410083 China

Deep crustal rocks of the Early Proterozoic orogenic belt (DCR)in Daqingshan area mainly included the synorogenicmetamorphic khondalite series and reworked Archeanbasement granulites. During the early stage about 1900～1800 Ma, the DCR consisted of five huge slices which obducted over and stacked up along a series of hightemperature shear zone (HTSZ), and were subsequently uplifted from the deep crustal level to the middle one accompanied with granuliteamphibolite facies retrometamorphic reworking in HTSZ. From 1800～1700 Ma, some slices and HTSZ mentioned above were oveprinted by several lowtemperature shear zone (LTSZ), of which the lowangle oblique thrusts caused these DCR to uplift again from the middle crustal level to the shallow  one, and experienced retrometamorphic reworking of greenschist facies. These two stages of uplifting processes should be included in an entire Early Proterozoic orogenic cycle.

关键词： deep crustal rocks orogenic belt upliftprocess Early Proterozoic

Influencing factors and evaluation application of regional crustal stability in the Bohai Strait

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China Geology 2019年第3期2卷 354-363页

作者： Sai Mei Hong-xian Chu Ling-yu Dong Zhong-hua Fang Pan-feng Li Fei-fei Zhang Rui Shan Tie-hu Zhao Qingdao Institute of Marine Geology China geological surveyMinistry of Natural ResourcesQingdao 266071China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

Due to the extremely complex geological conditions in the Bohai Strait, active faults is very developed and earthquake activity occurs frequently. It is of great importance to evaluate the regional crustal stability for the planning and construction of the Trans-straits Passage. In this study, the authors carry out the evaluation by means of buffer analysis, topology analysis and overlay analysis based on ArcGIS software. The evaluation mainly analyzed six assessment factors of Bohai Strait including neotectonic activity, active faults distribution, seismicity, tectonic stress fields, Bouguer gravity anomaly and geological disasters. In brief, the crustal stability of the eastern North Yellow Sea Basin is best, while that of the Bohai Basin and southwest Bohai Strait is poor. Meanwhile, small and frequent earthquakes in the southern Strait and geological disasters developed in the northern and central Strait such as tidal ridge and shallow gas which may adversely impact on the Trans-straits Passage construction.

关键词： Regional crustal stability Trans-straits Passage Coastal geological survey Engineering GIS Bohai Strait China

Gravity changes and crustal deformations before the Menyuan,Qinghai Ms6.4 earthquake of 2016

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Geodesy and Geodynamics 2019年第4期10卷 315-320页

作者： Shusong Guo Guoqing Zhang Yiqing Zhu The Second Monitoring and Application Center China Earthquake Administration

In this study, the relative gravity data(2012 e2015), GPS data-derived horizontal deformation(2011 e2014) and the background vertical deformation from the leveling measurements(1970 e2011) in the northeastern margin of Tibetan Plateau were processed to systematically analysis the mechanism of temporalespatial patterns and the relationship with Menyuan Ms6.4 earthquake. It can be summarized in the following: 1) The regional gravity changes, the GPS and the vertical deformational showed an intense spatial relationship: the gravity increased along with the direction of horizontal movement, and decreased with the crustal uplift and vice versa, which reflected the inherited characteristics of geotectonic activities. 2) The crustal deformations were closely related to the active faults. The contour lines of gravity changes and vertical deformation were generally along with the Qilian-Haiyuan fault(strike is NWW), and the crustal horizontal deformation showed left-lateral strike slip motion near the Qilian-Haiyuan fault. 3) Menyuan Ms6.4 earthquake occurred in the high negative gravity variation area and a high gradient formed in regions, positive and negative variation of gravity amount to 110 m ***, a borderline of positive and negative gravity located in the south of epicenter along the north edge of Qilianshan fault and Lenglongling fault, as well as the vertical and/or horizontal deformation is intensely. The extrusion deformation, surface compression rate and gravity changes were obvious near the epicenter of 2016 Menyuan Earthquake.

关键词： Northeastern edge of the Tibetan plateau Gravity change crustal deformations Menyuan Ms6.4 earthquake Tectonic activity

Episodic crustal growth in the Tanzania Craton:evidence from Nd isotope compositions

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China Geology 2018年第2期1卷 210-224页

作者： Kai Sun Lin-lin Zhang Zhi-dan Zhao Fu-qing He Sheng-fei He Xing-yuan Wu Lei Qiu Xiao-dong Ren Tianjin Centre China Geological SurveyTianjin 300170China China University of Geosciences (Beijing) Beijing 100083China Sinomine Rock and Mineral Analysis (Tianjin)Co. Ltd.Tianjin 300270China

The analysis of available Nd isotope data from the Tanzania Craton places important constraints on the crest-mantle separation ages,and events marking juvenile crustal addition and crustal *** model ages date the oldest crust extraction to 3.16 Ga in the Tanzania Craton,although a rock record of such antiquity is yet to be found *** most significant period of juvenile crustal addition as well as crustal recycling is 2.7-2.6 *** Nd isotopes of marie samples show that chemical heterogeneity existed in the mantle beneath the Tanzania Craton,with some samples originating from significantly depleted mantle, and most samples originating from the mixture of primitive mantle and depleted *** Nd isotope section reveals significant differences in Nd isotopes between the north eraton and central craton;compared to the north craton,the central craton yields a Nd model age that is approximately 100 Ma older, and its εNd(t)values are more negative,indicating that the two parts of the craton have different mantle source *** types of granitoids are distributed in the Tanzania Craton,such as high-K and low-Al granite,ealc-alkaline granite,peraluminous granite and transitional types of tonalite-trondhjemite- granodiorites (TTGs).Most of the granitoids formed later than the marie rocks in syn-collision and postcollision events.

关键词： Nd isotope Tanzania Craton crustal addition crustal recycling Block boundary

Surface seasonal mass changes and vertical crustal deformation in North China from GPS and GRACE measurements

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Geodesy and Geodynamics 2020年第1期11卷 46-55页

作者： Shuya Li Wenbin Shen Yuanjin Pan Tengxu Zhang School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China

The Earth is an elastic body,and the surface mass loading changes will lead to elastic loading deformation on the surface of the *** this study,we investigated the surface seasonal mass changes and vertical crustal deformation in North China using the data obtained by the techniques of the Global Positioning System(GPS),Gravity Recovery and Climate Experiment(GRACE)and Surface Loading Models(SLMs).The seasonal annual signal and semi-annual signal obtained by the three techniques show strong *** average value of the weighted root-mean-square(WRMS)of the all 30 sites is 58%after deducting the GRACE-obtained vertical deformation from the GPS-derived vertical ***,the consistency of results between GPS and SLMs is not so good,with a 31%mean WRMS reduction,due to the fact that the global SLMs perform not well in North *** GRACEmeasured long-term trend is deducted from the GPS-obtained vertical rates to reveal the crustal displacement caused by the underground factors such as tectonic movement and groundwater in North *** results show that the rates of stations HECX and TJBH are very large,more than 10 mm/yr,which suggests that the surface subsidence is caused by excessive exploitation of groundwater.

关键词： Continuous GPS measurement GRACE measurement Surface Loading Models Seasonal mass changes Vertical crustal displacement

Research on the crustal Velocity Model of the Yunnan Region and Its Application

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Earthquake Research in China 2018年第4期32卷 510-520页

作者： Yang Jingqiong Yang Zhousheng Zhang Huiyuan Yunnan Earthquake Agency Kunming 650203China

This paper selects the records of 7,412 earthquakes,each recorded by more than 10 stations in Yunnan between 2009 and 2014 to acquire the traveltime ***,for improving precision,linear analysis,reduced traveltime curve and interval stability analysis are conducted focusing on the records of 83 earthquakes with M_L≥3.0 recorded each by≥80%of the stations,and by combining predecessors'research results,the initial crustal velocity model of the study area is *** selecting 200 earthquakes with M≥3.0 occurring in Yunnan between 2010 and 2014,using the Hyposat batch location processing method to iterate the initial velocity model,and performing fitting to S waves layered velocity structure,we obtain the crustal velocity model for the Yunnan region,namely,the 2015 Yunnan model,with:v_(P1)=6.01km/s,v_(P2)=6.60km/s,v_(Pn)=7.89km/s,H_1=20km,H_2=21km,v_(S1)=3.52km/s,v_(S2)=3.86km/s,v_(Sn)=4.43km/*** on earthquake relocations based on the new model shows that most earthquakes occurring in Yunnan are at a depth of 10km-20km of the upper *** March 10,2011 M_S5.8Yingjiang and August 3,2014 M_S6.5 Ludian earthquakes are relocated,and the focal depths determined with the new model are respectively close to the precise positioning result and hypocentral distance to the strong motion stations at the epicenters,indicating that the new one-dimensional velocity model can better reflect the average velocity structure of the study area.

关键词： The Yunnan area crustal velocity model Earthquake location

The inversion of 3-D crustal structure and hypocenter location in the Beijing-Tianjin-Tangshan-Zhangjiakou area by genetic algorithm

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Acta Seismologica Sinica(English Edition) 1997年第6期10卷 74-86页

作者：万永革刘瑞丰李鸿吉 1. College of Disaster Prevention Technics State Seismological Bureau 101601 Yanjiao East of Beijing China2. Institute of Geophysics State Seismological Bureau 100081 Beijing China

This paper discusses the inversion of velocity structure and hypocenters location in the Beijing Tianjin Tangshan Zhangjiakou area by genetic algorithm. The hypocenters location of selected earthquakes and crustal structure of this area are obtained using the travel time data of local earthquakes acquired by the Telemetered Seismic Network of Northern China. The mean and standard residuals of hypocenter location acquired by this method are much less than those provided by the report of respective earthquakes. The crustal structure of the first and the second layers obtained interpret the outline of the plain and mountain area in the region successfully and the crustal structure of the third layer nearly coincides with the Moho discontinuity obtained by artificial seismic sounding. These show the genetic algorithm is effective to the inversion of hypocenter location and three dimensional velocity structure.

关键词： genetic algorithm hypocenter crustal structure inversion non linear

crustal Magnetization of Mars: Terra Meridiani and Terra Sirenum

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Journal of Modern Physics 2017年第8期8卷 1275-1293页

作者： Renee A. French Donna M. Jurdy Department of Earth and Planetary Sciences Northwestern University Evanston IL USA

We examine the crustal magnetization of Terra Meridiani and Terra Sirenum, the region representing the strongest magnetization in the Southern Hemisphere, by downward continuing mapping level data (400 km altitude) from the Mars Global Surveyor (MGS) Magnetometer and Electron Reflectometer (MAG/ER). We find that the surface magnetization in both regions can be fit with a small number of sources, with the positive sources stronger than negative ones in both regions. The ratio of the strongest positive to strongest negative source for the regions matches within 2%. For both regions, the locations of strong sources are positioned at the outer rings of ancient impact features. We employ two approaches of source depth estimation. One method employs downward continuation of positive and negative sources from mapping level into the subsurface to extrapolate the depth to magnetization. With this approach, source depths generally range from 80 ±20 km in Terra Meridiani and 65 ±25 km in Terra Sirenum. A graphical approach uses the contour map of surface magnetization to estimate depths ranging from 125 km for thick sources in Terra Meridiani and from 82 km for thick sources in Terra Sirenum. These depths require a low (≤∼20 mW/m2) Martian heat flux to permit magnetite, hematite, and/or pyrrhotite (although limited) as carriers through 100 km or more. The upcoming InSight mission will provide invaluable seismic constraints on both crustal and core structure, in addition to the first Martian heat flow measurements that will constrain magnetization.

关键词： Mars crustal Magnetization Magnetization Depth InSight Mission Geophysics