Geochemical characteristics and SHRIMP U-Pb dating of metamorphic zircons from allanite-bearing para- and ortho-gneiss in Sulu ultrahigh-pressure metamorphic (UHP) belt

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	Geochemical characteristics and SHRIMP U-Pb dating of metamorphic zircons from allanite-bearing para- and ortho-gneiss in Sulu ultrahigh-pressure metamorphic (UHP) belt
	Liu, FL (Liu FuLai); Xue, HM (Xue HuaiMin)
刊名	ACTA PETROLOGICA SINICA
	2007
卷号	23 期号:12 页码:3137-3152
关键词	orthogneiss and paragneiss zircon allanite higher oxygen fugacity Sulu UHP metamorphic belt
ISSN号	1000-0569
英文摘要	Laser Raman spectroscopy and cathodoluminescence (CL) images show that most zircons separated from allanite-bearing paragneiss (S27) and orthogneiss (S28) in drill hole CCSD-PP2 at Maobei, southwestern Sulu UHP terrane, retain low-P mineral-bearing inherited (detrital or magmatic) cores, coesite-hearing UHP mantles and retrogressive rims. LA-ICP-MS and SHRIMP U-Pb analyses of these zoned zircons identify three discrete and meaningful age groups Neoproterozoic protolith ages (> 810Ma) are recorded in the inherited cores, the UHP metamorphic event in the coesite-bearing zircon domains occurred at 241 similar to 223Ma (the weighted mean age is 229 +/- 7Ma and 230 +/- 7Ma for S27 and S28, respectively), and the late amphibolite-facies retrogression recorded in the outmost rims was at 217 similar to 200Ma (the weighted mean age is 210 +/- 2Ma and 211 +/- 3Ma for S27 and S28, respectively). Thus, the exhumation rate deduced from the SHRIMP and metamorphic P-T conditions for Sulu UHP terrane is 5.3km/Myr. Compared with the UHP zircon domains from common eclogite and its country-rocks in the Sulu-Dabie UHP terrane, the coesite-bearing zircon domains from S27 and S28 have unique trace element and rare earth element (REE) compositions. They are characterized by higher heavy rare earth element (HREE) content and lower U content (10 similar to 29 X 10(-6)) with higher Th/U ratios (0.45 similar to 0.92), which are genetically related to the compositions of UHP metamorphic allanite (being rich in light rare earth element) from the host-rocks. Moreover, lower U content and higher Th/U ratio of the coesite-bearing zircon domains are evidently controlled by higher oxygen fugacity during the UHP peak metamorphism.
学科主题	变质岩岩石学
WOS关键词	SUBDUCTED CONTINENTAL-CRUST ; EASTERN CHINA ; O-ISOTOPE ; MINERAL INCLUSIONS ; DABIE OROGEN ; TERRANE ; ECLOGITE ; AGES ; EXHUMATION ; PROTOLITH
WOS研究方向	Geology
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000254582000007
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38450]
专题	中国地质调查局
作者单位	Chinese Acad Geol Sci, Inst Geol, Key Lab Continental Dynam, Minist Land & Resources, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Liu, FL ,Xue, HM . Geochemical characteristics and SHRIMP U-Pb dating of metamorphic zircons from allanite-bearing para- and ortho-gneiss in Sulu ultrahigh-pressure metamorphic (UHP) belt[J]. ACTA PETROLOGICA SINICA,2007,23(12):3137-3152.
APA	Liu, FL ,&Xue, HM .(2007).Geochemical characteristics and SHRIMP U-Pb dating of metamorphic zircons from allanite-bearing para- and ortho-gneiss in Sulu ultrahigh-pressure metamorphic (UHP) belt.ACTA PETROLOGICA SINICA,23(12),3137-3152.
MLA	Liu, FL ,et al."Geochemical characteristics and SHRIMP U-Pb dating of metamorphic zircons from allanite-bearing para- and ortho-gneiss in Sulu ultrahigh-pressure metamorphic (UHP) belt".ACTA PETROLOGICA SINICA 23.12(2007):3137-3152.