Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry

doi:10.1016/j.precamres.2014.03.017

	Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry
	Meng, En 9; Liu, Fu-Lai ; Liu, Ping-Hua ; Liu, Chao-Hui ; Yang, Hong ; Wang, Fang ; Shi, Jian-Rong ; Cai, Jia 7
刊名	PRECAMBRIAN RESEARCH
	2014
卷号	247 页码:92-109
关键词	Paleoproterozoic meta-mafic rocks Zircon U-Pb-Hf isotopes Geochemistry Petrogenesis Tectonic implications Liaodong Peninsula
ISSN号	0301-9268
DOI	10.1016/j.precamres.2014.03.017
英文摘要	The central Liaodong Peninsula is located in the northwestern part of the Jiao-Liao-ji Belt in the Eastern Block of the North China Craton. Surface rocks in this region are voluminous meta-mafic rocks, which mainly comprise amphibolite and metamorphic gabbro or diabase. We present zircon cathodoluminescence images, U-Pb dates, and Lu-Hf isotope data, as well as whole-rock geochemical data for these rocks, in order to constrain the tectonic nature and evolution of the jiao-Liao-ji Belt. Zircons from these meta-mafic rocks can be divided into two groups, with one having a typical magmatic origin and the other a metamorphic origin. Zircon U-Pb dating and Lu-Hf isotopic results show that the magmatic zircons have two peak ages at 2503 and 2154 Ma, with the former have epsilon(Hf) = +7.1 to +8.1 and single-stage model ages (T-Hf) = 2.50-2.55 Ga, indicating that these captured or inherited zircons formed at ca. 2.50 Ga by partial melting of coeval juvenile crust. The younger magmatic zircons have epsilon(Hf) = +3.2 to +9.6, mainly varying from +7.4 to +9.6 (average = +8.7), and T-Hf = 2.15-2.34 Ga (peak at 2.19 Ga), suggesting that the meta-mafic rocks were emplaced at ca. 2.15 Ga and derived by partial melting of depleted mantle. The metamorphic zircons yield a peak age of 1897 Ma and have epsilon(Hf) = -4.5 to +6.8. These zircons can be further divided into three groups on the basis of Hf isotope data (i.e., epsilon(Hf) = -4.5 to -2.3, -0.6 to +1.0, and +3.1 to +6.8; T-Hf = 2.39-2.54, 2.26-2.39, and 2.03-2.11 Ga, respectively), indicating they were derived by reworking of Neoarchean-Paleoproterozoic ancient crust and some Paleoproterozoic juvenile crust. Thus there existed two crustal growth events at 2.50 and 2.15 Ga and one reworking event at ca. 1.90 Ga in the Eastern Block. Geochemical data show that these meta-mafic rocks are characterized by: SiO2 = 47.3-49.8 wt%; TiO2 = 0.97-1.59 wt.%; K2O = 0.39-1.95 wt.%; Na2O/K2O = 1.03-4.85; Mg# = 39-52; Cr = 29-247 ppm; and Ni =24.4-73.4 ppm. These features, combined with low total rare earth element concentrations (Sigma REE), relative enrichment in light REE, significant positive Rb, Ba, K, and P anomalies, and depletions in high-field strength elements (e.g., Nb, Ta, and Ti), indicate derivation by partial melting of depleted lithospheric mantle that had been metasomatized by subduction-derived fluids, with little or no crustal contamination during magma ascent. Given our dating results and the regional geological framework, we propose that the subduction in the eastern Longgang Block took place at least in age of 2.15 Ga, and that the meta-mafic rocks in the central Liaodong Peninsula may have formed in a back-arc basin. However, the tectonic location of this magmatic arc and its relationship with the Nangrim Block need to be further studied to confirm this hypothesis. (C) 2014 Elsevier B.V. All rights reserved.
学科主题	变质岩岩石学
WOS关键词	ULTRAHIGH-TEMPERATURE METAMORPHISM ; PRESSURE PELITIC GRANULITES ; EASTERN LIAONING-PROVINCE ; ARCHEAN CRUSTAL EVOLUTION ; SOUTH-LIAOHE-GROUP ; CRATON KEY ISSUES ; CONTINENTAL-CRUST ; JI BELT ; DETRITAL ZIRCONS ; JIAOBEI MASSIF
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000336821300005
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40495]
专题	中国地质科学院地质研究所
作者单位	1.[Meng, En 2.Liu, Fu-Lai 3.Liu, Ping-Hua 4.Liu, Chao-Hui 5.Yang, Hong 6.Wang, Fang 7.Shi, Jian-Rong 8.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 9.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Meng, En,Liu, Fu-Lai,Liu, Ping-Hua,et al. Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry[J]. PRECAMBRIAN RESEARCH,2014,247:92-109.
APA	Meng, En.,Liu, Fu-Lai.,Liu, Ping-Hua.,Liu, Chao-Hui.,Yang, Hong.,...&Cai, Jia.(2014).Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry.PRECAMBRIAN RESEARCH,247,92-109.
MLA	Meng, En,et al."Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry".PRECAMBRIAN RESEARCH 247(2014):92-109.