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SHRIMP zircon U-Pb dating of late Paleoproterozoic kondalites in the Daqing Mountains area on the North China Craton 被引量:47
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作者 DONG ChunYan WAN YuSheng +4 位作者 XU ZhongYuan LIU DunYi YANG ZhenSheng MA MingZhu XIE HangQiang 《Science China Earth Sciences》 SCIE EI CAS 2013年第1期115-125,共11页
The Daqing Mountains area comprises a typical occurrence of the Khondalite Belt in the Western Block of the North China Craton (NCC). In this area, both early and late Paleoproterozoic metasedimentary rocks have been ... The Daqing Mountains area comprises a typical occurrence of the Khondalite Belt in the Western Block of the North China Craton (NCC). In this area, both early and late Paleoproterozoic metasedimentary rocks have been identified in what was originally called the Upper Wula Mountains "Subgroup". Six metasedimentary rock samples yielded SHRIMP U-Pb zircon ages of 2.56-2.04 Ga for detrital and 1.96-1.83 Ga for metamorphic zircons. Based on these data and previously published results, the following conclusions can be drawn: 1) The source region for the late Paleoproterozoic detrital sedimentary rocks is mainly 2.55 2.4 and 2.2 2.04 Ga in age, consistent with the early Precambrian geological history identified widely in the basement of the NCC. 2) The majority of sedimentary rocks of the khondalite series were deposited between 2.04 and 1.95 Ga, and then in a protracted period (1.96 and 1.83 Ga) underwent a complex history of amphibolite to granulite-facies metamorphism. 展开更多
关键词 KHONDALITE PALEOPROTEROZOIC ZIRCON SHRIMP U-Pb dating daqing mountains North China Craton
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Parameters of the AD 849 earthquake east of Baotou City in Inner Mongolia and the adjustion of the potential seismic sources zone spatial distribution functions
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作者 Ji Wang Zhanwu Gao +3 位作者 Wei Xu Zhaode Yuan Zhicheng Liu Xiaoliang Zhang 《Earthquake Science》 2019年第3期170-178,共9页
According to volume 18(Xuanzong Ji Tang)of the historical book entitled the Old Book of Tang,the Hetao area of Inner Mongolia experienced a large earthquake in AD 849.However,previous work on that earthquake contains ... According to volume 18(Xuanzong Ji Tang)of the historical book entitled the Old Book of Tang,the Hetao area of Inner Mongolia experienced a large earthquake in AD 849.However,previous work on that earthquake contains many discrepancies regarding its epicenter location,magnitude,deaths,and intensity.While exploring active faults in Baotou City,the present authors mapped the Daqing Mountain piedmont fault geologically.Based on previous work,several seismic deformation traces of more than 1000 years ago were found,and dating tests were conducted.The research showed the Daqing Mountain piedmont fault zone to be the seismogenic structure of the AD 849 earthquake.The length of earthquake surface rupture zone was around 80 km,and the macro epicenter was located in the active fault.The deformation center was located at 40.6°N,110.2°E.By collecting and analyzing more historical data about the AD 849 earthquake,reinterpreting some existing historical data,and re-examining the contradictory numbers of deaths in the historical data,the present analysis concludes that around 10,000 people were dead.It is suggested that this earthquake had a magnitude of 7½.According to the revised seismic parameters and the paleoearthquake recurrence period of the Daqing Mountain piedmont fault,the boundary of some potential seismic sources zone in the Baotou area are adjusted and the recurrence period of M8 and M7.5 are re-calculated. 展开更多
关键词 EARTHQUAKE rupture traces parameters AD 849 daqing mountain piedmont fault
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