International Geology Review ISSN: 0020-6814 (Print) 1938-2839 (Online) Journal homepage: http://www.tandfonline.com/loi/tigr20 Detrital zircon geochronology of Devonian quartzite from tectonic mélange in the Mianlue Suture Zone, Central China: provenance and tectonic implications Xing-Zhong Ji, Li-Qiang Yang, M. Santosh, Nan Li, Chuang Zhang, Zhi-Chao Zhang, Ri Han, Zai-Chun Li & Chun-Jun Wu To cite this article: Xing-Zhong Ji, Li-Qiang Yang, M. Santosh, Nan Li, Chuang Zhang, Zhi- Chao Zhang, Ri Han, Zai-Chun Li & Chun-Jun Wu (2016) Detrital zircon geochronology of Devonian quartzite from tectonic mélange in the Mianlue Suture Zone, Central China: provenance and tectonic implications, International Geology Review, 58:12, 1510-1527, DOI: 10.1080/00206814.2016.1167635 To link to this article: http://dx.doi.org/10.1080/00206814.2016.1167635 View supplementary material Published online: 04 Apr 2016. Submit your article to this journal Article views: 75 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tigr20 Download by: [Shanghai Jiaotong University] Date: 17 October 2016, At: 00:27 INTERNATIONAL GEOLOGY REVIEW, 2016 VOL. 58, NO. 12, 1510–1527 http://dx.doi.org/10.1080/00206814.2016.1167635 Detrital zircon geochronology of Devonian quartzite from tectonic mélange in the Mianlue Suture Zone, Central China: provenance and tectonic implications Xing-Zhong Jia, Li-Qiang Yanga, M. Santosha,b, Nan Lia, Chuang Zhangc, Zhi-Chao Zhanga, Ri Hana, Zai-Chun Lia and Chun-Jun Wud aState Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, PR China; bDepartment of Earth Sciences, University of Adelaide, Adelaide, Australia; cDivision of Geology and Mineral Resources, Beijing Research Institute of Uranium Geology, Beijing, PR China; dTechnology Centre, 12th Gold Mine Detachment of the Chinese Armed Police Force, Chengdu, PR China ABSTRACT ARTICLE HISTORY Devonian quartzite occurs as blocks within a phyllite matrix in Puziba area of the Mianlue Suture Received 5 January 2016 Zone (MLSZ) in central China. The depositional time of the quartzite is younger than 425 Ma Accepted 15 March 2016 – (mainly Early Devonian), constrained by the zircon U Pb geochronology data from the quartzite, KEYWORDS cross-cutting relationships with granite, and palaeontology evidence. The detrital zircons in the Detrital zircon quartzite show typical magmatic features with four main age peaks at: 2676–2420 Ma (11.6% of geochronology; quartzite; the population), 1791–1606 Ma (4.8%), 997–817 Ma (26.5%), and 597–425 Ma (17.5%). In combi- Mianlue Suture; Qinling nation with the zircon εHf(t) values, we propose that the quartzite in the MLSZ was sourced from Orogen; tectonic evolution Neoproterozoic and Palaeozoic magmatic and sedimentary rocks in the South Qinling Block and the South China Block (particularly from the Bikou Terrane), with minor contributions from Archaean and Palaeoproterozoic magmatic units from both of the South and North China blocks. The blocks of quartzite, slate, marble, metasandstone, and chert blocks in the phyllite matrix in the Puziba area show a typical block-in-matrix texture in a tectonic mélange, and provide significant evidence from sedimentary rock blocks rather than ophiolite or volcanic rock for the existence of the MLSZ. 1. Introduction The lithostratigraphic compositions of the different tectonic units in the Qinling Orogen are complex. The S- The Qinling Orogen, the central orogenic belt in China, NCB is mainly composed of ancient basements (Ar – which separates the North and the South China blocks 3 Pt ), volcanic rocks (Pt ), clastic and carbonate sequence [Figure 1(A) and (B)], is bounded by the Lingbao– 1 2 (Pt –Pt ), tillite (Pt ), and passive continental margin Lushan–Wuyang Fault (LWF) in the north and the 2 3 3 successions (Є–O) (Dong and Santosh 2015). The NQB Mianlue–Bashan–Xiangguang Fault (MBXF) in the consists of the Kuanping Group (Pt –Pt ophiolite, Pt south (Dong and Santosh 2015). The Orogen itself can 1 2 3 sedimentary units), Erlangping Group (Palaeozoic ophio- be divided into the Southern North China Block (S-NCB), lite), Qinling Group (Precambrian basement of gneiss, the North Qinling Block (NQB), and the South Qinling amphibolite and marble, Neoproterozoic, and Block (SQB) by the Luonan–Luanchuan Fault (LLF), the Palaeozoic plutons), Songshugou Complex (Pt –Pt Shangdan Suture Zone (SDSZ), and the Mianlue Suture 1 2 ophiolite), and Danfeng Group (ophiolite) (Zhang et al. Zone (MLSZ) from north to south [Figure 1(B)], respec- 2003). The Shangdan Suture comprises Palaeozoic tively. The Shangdan and the Mianlue Sutures contain ophiolitic assemblages, subduction-related volcanic, magmatic and sedimentary rocks and structures that and sedimentary rocks (530–470 Ma). The SQB could can be used to reconstruct the continental rifting, open- be divided into the Northern and the Southern SQB ing and closing of the oceanic basin, and the subduc- because of the different lithostratigraphic units, and tion and collision processes between the North and the the boundary is near the E–W trend fault from South China Blocks (Zhang et al. 2003; Dong and Mianxian to Shangnan [Figure 1(B)] (Dong and Santosh Santosh 2015). 2015). The Northern SQB is primarily composed of CONTACT Li-Qiang Yang [email protected] State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, No. 29 Xueyuan Road, Beijing 100083, PR China Supplemental data for this article can be accessed here. © 2016 Informa UK Limited, trading as Taylor & Francis Group INTERNATIONAL GEOLOGY REVIEW 1511 Figure 1. (A) Simplified geological map showing the central Qinling–Dabie Orogen separating the North and the South China blocks. (B) The geological map of the Qinling Orogenic Belt, showing the Mianlue and the Shangdan suture zones (modified from Zhang et al. 2003; Dong and Santosh 2015). QL, Qilian Orogen; DB, Dabie Terrane; SL, Sulu orogenic belt. gneiss and amphibolite (Pt3), pelagic turbidite (D2–D3) Carboniferous to late Permian, and the large scale of and clastic rocks (C, P, T); while the Southern SQB mainly subduction occurred from Early–Middle Triassic), with consist of granitic gneiss, amphibolite and marble (Ar3), the final closure of the Mianlue Ocean and the conse- clastic and volcanic rocks (Pt3), clastic and carbonate quent continent–continent collision between the South rocks (Pt3), limestone (Є–O), shale (S), and minor clastic China Block and the SQB occurring in the Middle–Late rocks (D, C, P, T) (Dong and Santosh 2015). To the south, Triassic, which also represents the final collision of the the Mianlue Suture comprises Neoproterozoic and North and South China blocks (Zhang et al. 2003; Dong Palaeozoic ophiolite and volcanic rocks, and continental and Santosh 2015). The region subsequently trans- margin sedimentary rocks (Palaeozoic-T2) (Zhang et al. formed into an intra-continental tectonic setting in the 2003). The Bikou Terrane is mainly composed of Late Triassic (Zhang et al. 2003). Several important sedi- Neoarchaean Yudongzi Group (gneiss, amphibolite, mentary–metamorphic quartzite and hydrothermal gold greenschist, and quartzite), Neoproterozoic volcanic– deposits (Li et al. 2007, 2014; Liang et al. 2014; Zhou sedimentary rock, and turbidite (Wei 1994; Yan et al. et al. 2014), located within or near the MLSZ, have been 2004). The Dabie Terrane is an ultra-high pressure meta- correlated to the tectonic evolution of the Mianlue morphic terrane, and it consists of granitic and pelitic Suture and the SQB. Hence, research on the rock asso- gneisses, with minor eclogite, garnet–peridotite, pyrox- ciations in the MLSZ is significant not only to clarify the enite, marble, and jadeite–quartzite (Zhang et al. 2009). tectonic evolution of the Qinling Orogen but also pro- The MLSZ, separating the SQB and the South China vide information on the genesis of the ore deposits and Block [Figure 1(B)], is the boundary fault zone of the the ore-forming processes (Deng et al. 2014a, 2014b; southern margin of the central orogenic belt in China. Yang et al. 2016a, 2016b). Previous studies of the ophiolite complex, volcanic and In recent years, with the development of analytical intrusive rock suites, and sedimentary units within the facilities using laser ablation inductively coupled plasma MLSZ have shown that the suture formed during the mass spectrometry (LA-ICP-MS) for zircon geochronol- late Palaeozoic to early Mesozoic (Li et al. 2002; Zhang ogy, detrital zircons in clastic sedimentary rocks have et al. 2003; Wu and Zheng 2013). The rifting and open- been extensively used to constrain the maximum age of ing of the initial Mianlue oceanic basin occurred during deposition, provide source information of the sedi- the early Silurian to early Carboniferous (Li et al.(2002) ments, and unravel the tectono-sedimentary evolution suggested the rifting existed from the Early Devonian to of continental realms (Burrett et al. 2014; Spencer et al. early Carboniferous), with the ocean reaching its largest 2014; Wang et al. 2014; Henrique-Pinto et al. 2015). In extent during the early Carboniferous to mid-Permian addition, the Lu–Hf isotopic composition of detrital zir- (Zhang et al. 2003). Subduction of the Mianlue Ocean cons can provide important clues on crustal growth took place during the late Permian to Middle Triassic (Li (Roberts and Spencer 2015). et al.(2002) thought the subduction and expansion of In this paper, we report LA-ICP-MS U–Pb ages and the Mianlue Ocean were coexisted from early Lu–Hf isotopic compositions of detrital zircons in the 1512 X.-Z. JI ET AL. Devonian quartzite from the Puziba area of the MLSZ. (Zhang et al. 2003). Therefore, our research has focused Our results provide new constraints on the depositional on this segment. time and provenance of the Devonian quartzite, and The Mianxian–Wenxian–Maqu segment of the throw light on the tectonic evolution of the Mianlue MLSZ is located between the SQB and the Bikou Suture.