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201.
GAO Tianshan CHEN Jiangfeng XIE Zhi YANG Shenghong & YU Gang School of Earth Space Sciences University of Science Technol-ogy of China Hefei China 《科学通报(英文版)》2004,49(20):2198-2204
Abundantbasic-ultrabasicbodiescropoutintheDabie-Suluultrahighpressure(UHP)metamorphicbeltandoccurasgroupandband.Muchresearchworkhasbeencarriedoutonthebasic-ultrabasicbodiesandmadeagreatprogressespeciallyonmineralogy.ThediscoveryofmineralassemblagesofUHPmetamorphismandexsolvedlamellaesuggestthattherocksmaycomefromthedeepmantleorwasonceemplacedintotheshallowlevelofthecrustandthensubductedtothemantledepthsduringsub-ductionofthecrust[1—13].However,theiroriginandtec-tonicsettingarestillacontrov… 相似文献
202.
Fluid inclusions hidden in coesite-bearing zircons in ultrahigh-pressure metamorphic rocks from southwestern Sulu terrane in eastern China 总被引:14,自引:0,他引:14
LIU Fulai & XU Zhiqin Institute of Geology Chinese Academy of Geological Sciences Beijing China 《科学通报(英文版)》2004,49(4):396-404
Fluidinclusionstudiesarepowerfultoolsfordeci-pheringthefluidevolutionandfluid-rockinteractionin-volvingultrahigh-pressure(UHP)metamorphismofcrustalrocksatmantledepths.Thecompositionandprop-ertiesoffluidinclusionscanreflectthephysico-chemicalconditionsofthefluidsduringplatesubduction,UHPmetamorphismandexhumation.However,UHPmeta-morphicrockscommonlyexperiencedconsiderablede-compressionrelatedtotherapidexhumationprocess.Thishascausedtheinternalpressureoftheinclusionstrappedinthemetamorphicmin… 相似文献
203.
SHRIMP U-Pb zircon ages for the UHP metamorphosed granitoid gneiss in Altyn Tagh and their geological significance 总被引:3,自引:0,他引:3
ZHANG Anda LIU Liang SUN Yong CHEN Danling WANG Yan & LUO Jinhai Key Laboratory of Continental Dynamics of the Ministry of Education Department of Geology Northwest University Xi’an China Correspondence should be addressed to Liu Liang 《科学通报(英文版)》2004,49(23):2527-2532
Different types of UHP metamorphic rocks havebeen recently discovered in the Altyn Tagh[1—4], the north-ern margin of Qadam Basin[5—7], the southwestern Tian-shan Mountains[8,9] and the northern Qinling Moun-tains[10,11] in Central and Western China. And these areashave attracted focus attention of geologists at home andabroad to the studying of UHP metamorphism and conti-nental deep subduction. However, as newly discoveredUHP metamorphic terranes, some questions have beenarisen abou… 相似文献
204.
WUCailai YANGJingsui JosephL.Wooden SHIRendeng CHENSongyong AndersMeibom ChrisMattinson 《科学通报(英文版)》2004,49(16):1736-1740
The Yematan batholith crops out over 120 km^2 in the North Qaidam ultrahigh pressure (UHP) metamorphic belt. It consists of granodiorite, monzogranite and biotite granite and forms an irregular intrusion into Neoproterozoic gneiss that has undergone Caledonian UHP metamorphism. Zircons from the Yematan granodiorite yield a SHRIMP U-Pb age of 397 3 Ma. These granitic rocks have geochemical characteristics intermediate between I- and S-type granites, and are post-collisional. We suggest that the Yematan granitic rocks were formed during the last exhumation event of the North Qaidam UHP belt. 相似文献
205.
Electron microprobe chemical ages of monazite from Qinling Group in the Qinling Orogen: Evidence for Late PanAfrican metamorphism? 总被引:5,自引:0,他引:5
CHEN Qiang CHEN Nengsong WANG Qinyan SUN Min WANG Xinyu LI Xiaoyan SHU Guiming 《科学通报(英文版)》2006,51(21):2645-2650
Electron microprobe chemical dating was carried out on monazites enclosed in two gen-erations of mineral paragenesis of St Ky Grt and Sil And Grt St, respectively, from the Qinling Group. Two different ages, 520±23 Ma and 435±9 Ma, were obtained from these monazites. This indicates that the Qinling Group experienced a metamorphism during the Early Cambrian, which is probably in response to the Late Pan-African subduction-accretion tectonothermal event. 相似文献
206.
YU Xuehui ZHAO Zhidan ZHOU Su MO Xuanxue ZHU Deqing WANG Yonglei 《科学通报(英文版)》2006,51(13):1621-1627
A suite of Cenozoic ultra-potassic volcanic rocks and carbonatites are widespread along the Lixian-Dang- chang areas of western Qinling in Gansu Province. There are abundant mantle-derived xenoliths within these ultra-potassic volcanic rocks. Systemmatic … 相似文献
207.
SHRIMP U-Pb zircon dating for the dacite of the Sangxiu Formation in the central segment of Tethyan Himalaya and its implications 总被引:8,自引:0,他引:8
ZHU Dicheng PAN Guitang MO Xuanxue WANG Liquan LIAO Zhongli JIANG Xinsheng & GENG Quanru . Chengdu Institute of Geology Mineral Resources Chengdu China . China University of Geosciences Beijing China 《科学通报(英文版)》2005,50(6):563-568
The Tethyan Himalaya is located between the In-dus-Yarlung Zangbo suture zone to the north and HigherHimalayan crystallines to the south, paleogeographicallybelonging to the northern margin of “Greater India”. TheSangxiu Formation is used to define a series of specialstrata with rich volcanic interbeds, and is only distributedto the southeast of Yangzuoyong Co within 200 km×50 km along the eastern part of central Tethyan Hima-laya[1]. Based on overlapped relationships of strata andfos… 相似文献
208.
CAIYanjun WarrenBeck ZHANGZhaofeng 《科学通报(英文版)》2005,50(8):817-821
Based on the comparison of dating results among high-precision TIMS U-series and AMS ^14C as well as the published ^14C dating results and their band counting ages(i.e. calendar ages), this paper discusses the effect of dead carbon on the speleothem ^14C dating. The result shows that the fraction of incorporated dead carbon during the formation of speleothem varies. The change in the fraction of dead carbon would result in big deviation in the ^14C age of the speleothem. It is indispensable to take the dead carbon into consideration when dating the speleothem using the ^14C method or studying the atmospheric ^14C concentration during the past with the speleothem. 相似文献
209.
SHENGuanjun LIJiankun JiXueping 《科学通报(英文版)》2005,50(4):355-359
The cultural deposits at pits T1 and T2 in Zhangkou Cave are intercalated with several flowstone layers. U-series dates show that the capping and 2rid flowstone layers are Holocene of age. The 4th and 5th flowstone layers are ca. 55 and 110 ka old respectively. The lithic artifacts bracketed by them provide unequivocal evidence for hominid presence during this time interval. The ““temporal gap““ of hominid fossil, widely quoted as in support of the out-of-Africa hypothesis, is most probably an artifact due to systematic errors of dating techniques. The infillings under 6th flowstone layer date to >300 ka, much older than the previous estimate at 15 ka based on classical 14C dating of fossil bones, providing one more example of the limited reliability of this chronometer. With rich relics and favorable conditions for precise dating, this site is promising for further multidisciplinary studies to address issues concerning recent human evolution in China. 相似文献
210.
Paleomagnetic dating of the topmost terrace in Kouma,Henan and its indication to the Yellow River's running through Sanmen Gorges 总被引:2,自引:0,他引:2
PANBaotian WANGJunping GAOHongshan GUANQingyu WANGYong SUHuai LIBingyuan LIJijun 《科学通报(英文版)》2005,50(7):657-664
In the east of Xiaolangdi, many river terraces are developed at the exit of the Yellow River Gorges. Among them the terraces in Kouma, Yanshi of Henan Province are most typical, where the Yellow River developed three staircase terraces, among which the altitude of gravel stratum of the topmost terrace is 30-35 m higher than the river level.The top of the gravel stratum was covered by 60 m eolian loess deposits which have many brownish-red paleosol strips.And the paleosol $14 is at its bottom. Research on systematic magnetostratigraphy and paleosol-loess matching indicates that the bottom age of the loess on the topmost terrace is 1165 ka. Therefore, it can be concluded that the terrace develops no later than 1.165 Ma and the situation that the Yellow River runs through Sanmen Gorges and inpours into East China Sea happened at least before 1.165 Ma. 相似文献