SHRIMP zircon U-Pb ages and REE partition for high-grade metamorphic;rocks in the North Dabie complex: Insight into crustal evolution with;respect to Triassic UHP metamorphism in east-central China

	SHRIMP zircon U-Pb ages and REE partition for high-grade metamorphic;rocks in the North Dabie complex: Insight into crustal evolution with;respect to Triassic UHP metamorphism in east-central China
	Jian, Ping 4; Kroener, Alfred ; Zhou, Gaozhi
刊名	CHEMICAL GEOLOGY
	2012
卷号	328;SI SI 页码:49-69
关键词	Zircon Monazite REE Granulite North Dabie complex Continental collision
ISSN号	024QY
英文摘要	We present SHRIMP U-Pb ages and REE data for zircon of two granulites, a garnet pyroxenite and a clinopyroxene amphibolite from the North Dabie complex. The North Dabie complex is a major fault-bounded petrotectonic unit in the Dabie continental collisional orogen between the South and North China Blocks. Zircon REE data are applied to link ages to specific petrological processes. In addition to SHRIMP zircon U-Pb dating, measurements were made on monazites from a HP-UHT metapsammitic granulite. Metamorphic zircon grains and coeval overgrowths on detrital cores from one granulite yielded a weighted mean Pb-207/Pb-206 age of 2042 +/- 7 Ma, corresponding to peak HP/UHT metamorphism. The zircon cores have well-preserved oscillatory, magmatic growth zoning and generated a range of Pb-207/Pb-206 ages from 2766 +/- 8 Ma to 3089 +/- 3 Ma, representing the detrital source. Concordant analyses of monazites from the same granulite sample yielded a weighted mean Pb-207/Pb-206 age of 2001 +/- 6 Ma, which we interpret as the time of exhumation to the middle crustal level. A magnetite-orthopyroxene-garnet quartzite associated with a banded iron formation has a metamorphic zircon age of 2293 +/- 7 Ma (granulite-facies) with a detrital core age of 2435 +/- 28 Ma. These results are interpreted to indicate a composite affinity to the South China and North China Blocks for the ancient Archean-Paleoproterozoic crust in the North Dabie metamorphic rocks. The garnet pyroxenite, known as a typical HP-UHP granulite, contains a multiple, latest Permian to Triassic metamorphic zircon population with Pb-206/U-238 ages of ca. 254-253, ca. 242-226, ca. 210, and ca. 203 Ma. Along with published zircon and titanite U-Pb age data and mineralogical evidence, we suggest that the HP-UHP granulite evolved broadly synchronously with UHP eclogites during continental collision in the latest Permian to Triassic. In the garnet pyroxenite, there is also zircon inheritance of variable ages (ca. 291-2477 Ma), indicative of a probable sedimentary origin of the protolith; there also occur young, mid-Jurassic to Cretaceous zircons ranging in age between 165 and 112 Ma, signifying considerable crustal reworking in mid-Jurassic and Cretaceous times. Zircons from the clinopyroxene amphibolite have a weighted mean Pb-206/U-238 age of 780 +/- 6 Ma representing the minimum time of protolith emplacement, and 133 +/- 2 Ma for an anatectic event in the postcollisional stage. The age data of this amphibolite are similar to those of granitic gneisses/migmatites in the North Dabie complex. The new U-Pb zircon ages for the North Dabie rocks provide constraints on the affinity of collided crustal blocks, the metamorphic history of HP-UHP granulites, and post-collisional crustal reworking. (C) 2012 Elsevier B.V. All rights reserved.
学科主题	变质岩岩石学
WOS关键词	TRACE-ELEMENT GEOCHEMISTRY ; SUBDUCTED CONTINENTAL-CRUST ; ZONE SOUTHERN ; ALPS ; SULU OROGENIC BELT ; ULTRAHIGH-PRESSURE METAMORPHISM ; GRANULITE-FACIES METAMORPHISM ; MELANGE-FORMING PROCESSES ; BULK ; COMPOSITION CONTROL ; O-ISOTOPE EVIDENCE ; HUANGTULING GRANULITE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	Dr. Ian S. Williams advised PJ in SHRIMP U-Th-Pb and REE methodology;when visiting Beijing, and the manuscript benefitted from discussion;with professors Y.-F. Zheng, S.G. Li, B.-m. Jahn, S.T. Xu, and Z.M.;Zhang. Two anonymous reviewers are gratefully acknowledged, and we;appreciate the editorial patience of Yong-Fei Zheng (Guest Editor) and;Klaus Mezger (Editor-in-Chief). The Natural Science Foundation of China;(Grant no. 41030314) supported this research. PJ is particularly;indebted to the late Dr. Shen-Su Sun who spent his last energy and;months in thoughtfully helping PJ and coauthors in their Dabie UHP;zircon work (EPSL 250, 650-666, 2006), and this paper is dedicated to;his memory.
WOS记录号	WOS:000310124900003
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39644]
专题	中国地质科学院地质研究所
作者单位	1.Chinese Acad Geol Sci, SHRIMP Ctr, Inst Geol, Beijing 100037, Peoples R China. 2.Johannes Gutenberg Univ Mainz, Inst Geowissensch, D-55099 Mainz, Germany. 3.Hubei Geol Survey, Wuhan 430034, Peoples R China. 4.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Jian, Ping,Kroener, Alfred,Zhou, Gaozhi. SHRIMP zircon U-Pb ages and REE partition for high-grade metamorphic;rocks in the North Dabie complex: Insight into crustal evolution with;respect to Triassic UHP metamorphism in east-central China[J]. CHEMICAL GEOLOGY,2012,328;SI SI:49-69.
APA	Jian, Ping,Kroener, Alfred,&Zhou, Gaozhi.(2012).SHRIMP zircon U-Pb ages and REE partition for high-grade metamorphic;rocks in the North Dabie complex: Insight into crustal evolution with;respect to Triassic UHP metamorphism in east-central China.CHEMICAL GEOLOGY,328;SI SI,49-69.
MLA	Jian, Ping,et al."SHRIMP zircon U-Pb ages and REE partition for high-grade metamorphic;rocks in the North Dabie complex: Insight into crustal evolution with;respect to Triassic UHP metamorphism in east-central China".CHEMICAL GEOLOGY 328;SI SI(2012):49-69.