Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane insights from mineral inclusions, trace elements, U-Pb and Lu-Hf isotope analyses of zircon in orthogneiss

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	Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane insights from mineral inclusions, trace elements, U-Pb and Lu-Hf isotope analyses of zircon in orthogneiss
	Liu, FL (Liu, F. L.)3; Gerdes, A (Gerdes, A.); Xue, HM (Xue, H. M.)
刊名	JOURNAL OF METAMORPHIC GEOLOGY
	2009
卷号	27 期号:9 页码:805-825
关键词	differential subduction and exhumation Lu-Hf isotope mineral inclusions orthogneiss REE SHRIMP U-Pb dating Sulu UHP terrane zircon
ISSN号	0263-4929
英文摘要	Based on new evidence the Sulu orogen is divided from south-east to north-west into high-pressure (HP) crustal slice I and ultrahigh-pressure (UHP) crustal slices II and III. A combined set of mineral inclusions, cathodoluminescence images, U-Pb SHRIMP dating and in situ trace element and Lu-Hf isotope analyses was obtained on zircon from orthogneisses of the different slices. Zircon grains typically have three distinct domains that formed during crystallization of the magmatic protolith, HP or UHP metamorphism and late-amphibolite facies retrogression, respectively (i) oscillatory zoned cores, with low-pressure (LP) mineral inclusions and Th/U > 0.38; (ii) high-luminescent mantles (Th/U < 0.10), with HP mineral inclusions of Qtz + Grt + Arg + Phe + Ap for slice I zircon and Coe + Grt + Phe + Kfs + Ap for both slices II and III zircon; (iii) low-luminescent rims, with LP mineral inclusions and Th/U < 0.08. Zircon U-Pb SHRIMP analyses of inherited cores point to protolith ages of 785-770 Ma in all seven orthogneisses. The ages recorded for UHP metamorphism and subsequent retrogression in slice II zircon (c. 228 and c. 215 Ma, respectively) are significantly older than those of slice III zircon (c. 218 and c. 202 Ma, respectively), while slice I zircon recorded even older ages for HP metamorphism and subsequent retrogression (c. 245 and c. 231 Ma, respectively). Moreover, Ar-Ar biotite ages from six paragneisses, interpreted as dating amphibolite facies retrogression, gradually decrease from HP slice I (c. 232 Ma) to UHP slice II (c. 215 Ma) and UHP slice III (c. 203 Ma). The combined data set suggests decreasing ages for HP or UHP metamorphism and late retrogression in the Sulu orogen from south-east to north-west. Thus, the HP-UHP units are interpreted to represent three crustal slices, which underwent different subduction and exhumation histories. Slice I was detached from the continental lithosphere at similar to 55-65 km depth and subsequently exhumed while subduction of the underlying slice II continued to similar to 100-120 km depth (UHP) before detachment and exhumation. Slice III experienced a similar geodynamic evolution as slice II, however, both UHP metamorphism and subsequent exhumation took place c. 10 Myr later. Magmatic zircon cores from two types of orthogneiss in UHP slices II and III show similar mid-Neoproterozoic crystallization ages, but have contrasting Hf isotope compositions (epsilon Hf((similar to 785)) = -2.7 to +2.2 and -17.3 to -11.1, respectively), suggesting their formation from distinct crustal units (Mesoproterozoic and Paleoproterozoic to Archean, respectively) during the breakup of Rodinia. The UHP and the retrograde zircon domains are characterized by lower Th/U and 176Lu/177Hf but higher 176Hf/177Hf(t) than the Neoproterozoic igneous cores. The similarity between UHP and retrograde domains indicates that late retrogression did not significantly modify chemical and isotopic composition of the UHP metamorphic system.
学科主题	变质岩岩石学
WOS关键词	ULTRAHIGH-PRESSURE ECLOGITE ; COESITE-BEARING ZIRCON ; SCIENTIFIC-DRILLING PROJECT ; EAST-CENTRAL CHINA ; CONTINENTAL-CRUST ; OXYGEN-ISOTOPE ; RETROGRADE METAMORPHISM ; PBSHRIMP GEOCHRONOLOGY ; JIANGSU-PROVINCE ; ROCKS
WOS研究方向	Geology
语种	英语
出版者	WILEY-BLACKWELL PUBLISHING, INC
WOS记录号	WOS:000271523900014
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38934]
专题	中国地质调查局
作者单位	1.[Liu, F. L. 2.Xue, H. M.] Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China [Gerdes, A.] Inst Geowissensch, D-60438 Frankfurt, Germany 3.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Liu, FL ,Gerdes, A ,Xue, HM . Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane insights from mineral inclusions, trace elements, U-Pb and Lu-Hf isotope analyses of zircon in orthogneiss[J]. JOURNAL OF METAMORPHIC GEOLOGY,2009,27(9):805-825.
APA	Liu, FL ,Gerdes, A ,&Xue, HM .(2009).Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane insights from mineral inclusions, trace elements, U-Pb and Lu-Hf isotope analyses of zircon in orthogneiss.JOURNAL OF METAMORPHIC GEOLOGY,27(9),805-825.
MLA	Liu, FL ,et al."Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane insights from mineral inclusions, trace elements, U-Pb and Lu-Hf isotope analyses of zircon in orthogneiss".JOURNAL OF METAMORPHIC GEOLOGY 27.9(2009):805-825.