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Constraints of late Cambrian mafic rocks from the Qushi'ang ophiolite on a back-arc system in a continental margin, East Kunlun Orogen, Western China

Published on Jan 1, 2019in Journal of Asian Earth Sciences2.76
· DOI :10.1016/j.jseaes.2018.08.006
Ruibao Li3
Estimated H-index: 3
(Chang'an University),
Xianzhi Pei4
Estimated H-index: 4
(Chang'an University)
+ 7 AuthorsKeng Feng (Chang'an University)
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Abstract
Abstract Early Palaeozoic ophiolites emplaced in the central East Kunlun fault zone (CEKF) offer critical clues to the tectonic evolution of the Proto-Tethys ocean and the accretionary process of CEKF. The Qushi'ang Ophiolite, located within the eastern segment of the CEKF, consists of dismembered serpentinites, meta-gabbros and meta-basalts. This study presents petrologic, whole-rock geochemical, and in situ zircon U-Pb and Hf isotope data for basic rocks (both metagabbros and metabasalts) from the Qushi'ang ophiolite to constrain the formation age and tectonic setting of the ophiolite. Zircons from two meta-gabbro samples yield concordant U-Pb ages of ca. 498 Ma and ca. 505 Ma, indicating that the Qushi'ang ophiolite was formed in the late Cambrian. The meta-gabbros and meta-basalts show significant enrichment in large ionic lithophile elements (LILEs), such as Cs, Rb, Ba, U, and Pb, and depletion in high field strength elements (HFSEs), such as Nb, Ta, Zr, and Ti, suggesting the influence of fluids derived from a subducting oceanic slab. On the N-MORB normalized trace element diagrams, these rocks share similar features with arc basalts and back-arc basalts and far away from fore-arc basalts (FABs) and normal mid-ocean basalts (N-MORBs). Low zircon e Hf (t) values (−2.9 to +0.2) for the meta-gabbros further indicate that the Qushi'ang ophiolite likely originated from an weakly enriched mantle wedge source. Geochemical discrimination diagrams show that the Qushi'ang ophiolite formed in a back arc basin setting. Our new analyses, combined with previous data, suggest that the Qushi'ang ophiolite represents a relict of a nascent back-arc basin, similar to the scenario of the Okinawa trough in Western Pacific.
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  • Citations (1)
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References70
Newest
Published on Dec 10, 2018in International Geology Review3.00
Ruibao Li3
Estimated H-index: 3
(Chang'an University),
Xianzhi Pei4
Estimated H-index: 4
(Chang'an University)
+ 6 AuthorsMeng Wang3
Estimated H-index: 3
(Chang'an University)
ABSTRACTThe Acite ophiolitic melange represents a remnant of the Proto-Tethys forearc oceanic lithosphere. Two gabbros yield zircon 206Pb/238U ages of 510-512 Ma. The magmatic rocks are divided into three subtypes: (1) Mid-ocean ridge basalt (MORB) -like forearc basalts (FABs), (2) Low-titanium tholeiitic gabbros (LTGs), and (3) Normal calc-alkaline dacites (CADs). The FABs have comparatively higher TiO2 concentrations (1.13–1.42 wt%) and show almost flat REE patterns. In the NMORB normalized tr...
Published on Dec 1, 2017in Earth-Science Reviews9.53
Yunpeng Dong21
Estimated H-index: 21
(Northwest University (United States)),
Dengfeng He8
Estimated H-index: 8
(Northwest University (United States))
+ 7 AuthorsJianhua Li13
Estimated H-index: 13
(HKU: University of Hong Kong)
Abstract The Kunlun Orogen is generally divided into the East Kunlun Orogenic Belt (E-KOB) and the West Kunlun Orogenic Belt (W-KOB) by the Altyn Tagh fault. The E-KOB forms part of the western segment of the Central China Orogenic System (CCOS), and is considered to have formed by the collision between the Qaidam Block and Qiangtang or Bayanhar Terrane as a consequence of the closure of the Kunlun Ocean (branch of the Paleo-Tethyan Ocean). Based on a compilation recently published high-quality ...
Published on Mar 11, 2016in International Geology Review3.00
Ruibao Li3
Estimated H-index: 3
(Chang'an University),
Xianzhi Pei4
Estimated H-index: 4
(Chang'an University)
+ 6 AuthorsTing Kou1
Estimated H-index: 1
ABSTRACTMid-Neoproterozoic rift-related Tadong amphibolites (TDA) are situated in the junction of the East Kunlun Orogen (EKO) and the West Qinling Orogen (WQO) in western China, and have important significance in the break-up of the Supercontinent Rodinia. The mineral assemblage of the TDA exhibits amphibolite facies metamorphism, and the protolith is basic volcanic rocks. Here, we present a detailed laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb age and geo...
Published on Jan 1, 2016
LISanzhong44
Estimated H-index: 44
,
Zhao Shujuan2
Estimated H-index: 2
+ 11 AuthorsYan Zhen6
Estimated H-index: 6
Published on Jun 1, 2015in Journal of Asian Earth Sciences2.76
Ruibao Li3
Estimated H-index: 3
(Chang'an University),
Xianzhi Pei4
Estimated H-index: 4
(Chang'an University)
+ 6 AuthorsJie Yang2
Estimated H-index: 2
(Chang'an University)
Abstract The Yikehalaer intrusives are distributed in the Buqingshan tectonic melange belt at the southern margin of East Kunlun, China. They tectonically intruded the conglomerate of Permian Gequ Formation to the south and the marble of Mesoproterozoic Kuhai Group to the north. These intrusives mainly consist of off-white coarse- and fine-grained granodiorite and granite. U–Pb dating of zircons from the intrusive samples yielded weighted mean 206 Pb/ 238 U ages of 436 ± 7 Ma and 437 ± 6 Ma, ind...
Published on May 1, 2015in Journal of Asian Earth Sciences2.76
Yunpeng Dong21
Estimated H-index: 21
(Northwest University (United States)),
Xiaoning Zhang7
Estimated H-index: 7
(Northwest University (United States))
+ 7 AuthorsFeifei Zhang3
Estimated H-index: 3
(Northwest University (United States))
Abstract The Qinling Orogen was built through collision between the North China and South China Blocks. Previous detailed geological, geochemical and geochronological investigations revealed that the mountain range can be divided into four tectonic units with distinct tectono-lithostratigraphy, which are, from north to south, the southern sector of the North China Block, North Qinling Belt, South Qinling Belt and northern sector of the South China Block, separated by the Kuanping, Shangdan and M...
Published on Feb 1, 2015in Gondwana Research6.48
Fancong Meng1
Estimated H-index: 1
,
Meihui Cui1
Estimated H-index: 1
+ 1 AuthorsYufeng Ren1
Estimated H-index: 1
Abstract The Heishan mafic–ultramafic complex in the Qimantag Mountains of the Eastern Kunlun Orogen, consists of olivine pyroxenites, pyroxenites, gabbros, and massive basalts. Zircons from the gabbros have magmatic sector zoning, with Th/U ratios of 0.5–2.3, and yield a SHRIMP age of 486 ± 6 Ma (MSWD = 0.31), which is taken as the time of magma crystallization. Spinel, pyroxene, and plagioclase mineral compositions indicate that the rocks formed in an island arc environment. The cumulates have...
Published on Apr 1, 2014in Elements4.22
Yildirim Dilek50
Estimated H-index: 50
(Miami University),
Harald Furnes46
Estimated H-index: 46
(University of Bergen)
Ophiolites are suites of temporally and spatially associated ultramafic, mafic, and felsic rocks that are interpreted to be remnants of ancient oceanic crust and upper mantle. Ophiolites show significant variations in their internal structure, geochemical fingerprints, and emplacement mechanisms. These differences are controlled by (1) the proximity, when formed at the magmatic stage, to a plume or trench; (2) the rate, geometry, and nature of ocean-ridge spreading; (3) mantle composition, tempe...
Published on Feb 1, 2014in Earth-Science Reviews9.53
Shuguang Song35
Estimated H-index: 35
(PKU: Peking University),
Yaoling Niu63
Estimated H-index: 63
(CAS: Chinese Academy of Sciences)
+ 2 AuthorsLifei Zhang41
Estimated H-index: 41
(PKU: Peking University)
The North Qaidam ultra-high pressure metamorphic (UHPM) belt in the northern Tibetan Plateau records a complete history of the evolution of a continental orogen from prior seafloor subduction, to continental collision and subduction, and to the ultimate orogen collapse in the time period from the Neoproterozoic to the Paleozoic. Lithologies in this UHPM belt consist predominantly of felsicgneisses containing blocks of edogite and peridotite. The 1120-900 Ma granitic and psammitic/pelitic gneisse...
Published on Jan 1, 2014
R.L. Rudnick1
Estimated H-index: 1
(UMD: University of Maryland, College Park),
S. Gao1
Estimated H-index: 1
This chapter reviews the present-day composition of the continental crust, the methods employed to derive these estimates, and the implications of the continental crust composition for the formation of the continents, Earth differentiation, and its geochemical inventories. We review the composition of the upper, middle, and lower continental crust. We then examine the bulk crust composition and the implications of this composition for crust generation and modification processes. Finally, we comp...
Cited By1
Newest
Published on Jun 1, 2019in Arabian Journal of Geosciences1.14
Zuochen Li (Ontario Ministry of Natural Resources), Xianzhi Pei (Ontario Ministry of Natural Resources)+ 7 AuthorsShaowei Zhao (Ontario Ministry of Natural Resources)
This study focuses on the zircon U–Pb geochronology and geochemistry of intermediate–basic dikes from the Buqingshan–A’nyemaqen tectonic melange belt (BTMB) along the southern margin of the East Kunlun orogenic belt (EKOB). Zircons from a diorite dike show oscillatory zoning and relatively high Th/U ratios (0.47–2.43), indicating that they are of magmatic origin. Using LA–ICP–MS, zircons of the diorite dike yield a U–Pb age of 205 ± 1 Ma (MSWD = 0.88), implying that the diorite dikes were formed...
View next paperGeochemical Characteristics of Ophiolites in Yongzhu-Guomangcuo, Tibet and Its Tectonic Significance