Zircon Hf-O isotope and whole-rock geochemical constraints on origin of postcollisional mafic to felsic dykes in the Sulu orogen

doi:10.1016/j.lithos.2011.06.006

	Zircon Hf-O isotope and whole-rock geochemical constraints on origin of postcollisional mafic to felsic dykes in the Sulu orogen
	Zhang, Juan 1; Zhao, Zi-Fu 1; Zheng, Yong-Fei 1; Liu, Xiaoming 2; Xie, Liewen 3
刊名	LITHOS
	2012-04-01
卷号	136 页码:225-245
关键词	Crust-mantle interaction Continental subduction Postcollisional igneous rocks Petrogenesis Orogenic lithospheric mantle
ISSN号	0024-4937
DOI	10.1016/j.lithos.2011.06.006
文献子类	Article
英文摘要	Postcollisional mafic to felsic dykes in the western part of the Sulu orogen consist of monzogranite, diorite, plagioclase-bearing hornblendite and gabbro. LA-ICPMS zircon U-Pb dating yielded broadly consistent ages of 111 +/- 3 to 129 +/- 1 Ma for their crystallization, with Neoproterozoic ages of 743 +/- 9 to 773 +/- 9 Ma for residual cores. The mafic to felsic dykes are characterized by the arc-like patterns of trace element distribution with positive LILE and LREE anomalies but negative HFSE anomalies in the spidergram. They have high initial Sr-87/Sr-86 ratios of 0.7079 to 0.7100 and variably negative epsilon(Nd)(t) values of -21.6 to -13.6 for whole-rock Zircons also have highly negative epsilon(Hf)(t) values of -36.7 to -10.6, with two-stage Hf model ages of 1.84 to 3.47 Ga. The zircons exhibit relatively consistent delta O-18 values of 4.57 to 5.98 parts per thousand only some of them being slightly deviated from those for the normal mantle. The radiogenic isotope signatures for the mafic dykes require their derivations from isotopically enriched mantle sources, whereas the trace element compositions suggest that the mantle sources were metasomatized by arc-like crustal melts. Thus, the mantle sources may be generated by the reaction between the mantle-wedge peridotite and the felsic melts from the subducting continental crust during the Triassic continental collision. Nevertheless, there are significant differences in some element contents and slight differences in Nd-Hf isotope compositions between the gabbro and hornblendite, suggesting their derivation from different compositions of orogenic lithospheric mantle. The gabbro has relatively high MgO, Cr and Ni contents but low Al2O3 contents, indicating its derivation from an orthopyroxene-rich mantle source. The hornblendite displays relatively high Al2O3 and K2O contents but low MgO, Cr and Ni contents, suggesting its derivation from a hydrous (amphibole-rich) mantle source. On the other hand, there are general similarities in element and isotope characteristics between the felsic-intermediate dykes (monzogranite and diorite) and the widespread postcollisional Early Cretaceous granitoids in the Dabie-Sulu orogenic belt. This indicates their derivation from similar crustal sources, i.e. the subducted continental crust of the South China Block Therefore, the mafic to felsic dykes originated from partial melting of the orogenic lithosphere that included ultramafic pyroxenite and hornblendite which acted as sources for the mafic magmatism. (C) 2011 Elsevier B.V. All rights reserved.
WOS关键词	U-PB AGE ; SUBDUCTED CONTINENTAL-CRUST ; PRESSURE METAMORPHIC ROCKS ; NORTHERN DABIE COMPLEX ; EAST-CENTRAL CHINA ; NEOPROTEROZOIC RIFT MAGMATISM ; ULTRAHIGH-PRESSURE ; SOUTH CHINA ; TRACE-ELEMENT ; LITHOSPHERIC MANTLE
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000302517900014
资助机构	Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Ministry of Science and Technology(2009CB825004) ; Chinese Ministry of Science and Technology(2009CB825004) ; Natural Science Foundation of China(40921002 ; Natural Science Foundation of China(40921002 ; 41073025) ; 41073025) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Ministry of Science and Technology(2009CB825004) ; Chinese Ministry of Science and Technology(2009CB825004) ; Natural Science Foundation of China(40921002 ; Natural Science Foundation of China(40921002 ; 41073025) ; 41073025) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Ministry of Science and Technology(2009CB825004) ; Chinese Ministry of Science and Technology(2009CB825004) ; Natural Science Foundation of China(40921002 ; Natural Science Foundation of China(40921002 ; 41073025) ; 41073025) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Academy of Sciences(KZCX2-YW-Q08-3) ; Chinese Ministry of Science and Technology(2009CB825004) ; Chinese Ministry of Science and Technology(2009CB825004) ; Natural Science Foundation of China(40921002 ; Natural Science Foundation of China(40921002 ; 41073025) ; 41073025)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84118]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhao, Zi-Fu
作者单位	1.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei 230026, Peoples R China 2.NW Univ Xian, Dept Geol, State Key Lab Continental Dynam, Xian 710069, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithosphere Evolut, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Juan,Zhao, Zi-Fu,Zheng, Yong-Fei,et al. Zircon Hf-O isotope and whole-rock geochemical constraints on origin of postcollisional mafic to felsic dykes in the Sulu orogen[J]. LITHOS,2012,136:225-245.
APA	Zhang, Juan,Zhao, Zi-Fu,Zheng, Yong-Fei,Liu, Xiaoming,&Xie, Liewen.(2012).Zircon Hf-O isotope and whole-rock geochemical constraints on origin of postcollisional mafic to felsic dykes in the Sulu orogen.LITHOS,136,225-245.
MLA	Zhang, Juan,et al."Zircon Hf-O isotope and whole-rock geochemical constraints on origin of postcollisional mafic to felsic dykes in the Sulu orogen".LITHOS 136(2012):225-245.