中朝克拉通老于38亿年的残余陆壳──离子探针质谱锆石微区U-Pb年代学证据 |
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关键词:zircons ion microprobe U-Pb dating Sino-Korean craton |
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THE REMNANTS OF ≥3 800 Ma CRUST IN SINO-KOREAN CRATON───THE EVIDENCE FROM ION MICROPROBE U-Pb DATING OF ZIRCONS |
Ion microprobe U- Pb analyses of zircons from the Sino-Korean craton have identified remnants of≥3800 Ma crust at two localities-near Caozhuang east of Beijmg,and near Anshan,northeast China,Near Caozhuang,the detrital zircons in an Archean metaquartzite are 3550 Ma or older;about one-fourth have ages beween 3 800 and 3 850 Ma.The ages for detrital zircons with concor-dant U-Pb ages form a polymodal distribution, interpreted to show that the detritus that formed the quartzite was derived from a terrane containing early Archean rocks of several ages.Near Anshan,sheared gneiss is present in a complex containing ca.3300 and 3000 Ma granites,Some ̄(207)Pb/ ̄(206)Pb age of 3 804±5 Ma(2σ),interpreted to be the age of the protolith of the gneiss. |
LIU Dun-yi,A. P. Nutman,J.S.Williams,W.Compston,WU Jia-shan,SHEN Qi-han.1994.THE REMNANTS OF ≥3 800 Ma CRUST IN SINO-KOREAN CRATON───THE EVIDENCE FROM ION MICROPROBE U-Pb DATING OF ZIRCONS[J].Acta Geoscientica Sinica,15(1,2):3-13. |
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