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

Li, Ruibao; Pei, Xianzhi; Wei, Bo; Li, Zuochen; Pei, Lei; Chen, Youxin; Liu, Chengjun; Cheng, Guochao; Wang, Meng; Feng, Keng

doi:10.1016/j.jseaes.2018.08.006

Cited by 25 publications

(3 citation statements)

References 58 publications

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“…537–243 Ma (Dong et al, 2021; Dong, He, et al, 2018). The SSZ type ophiolites are widely distributed in Tatuo (522 Ma; Wei, 2015), Qushiang (505–498 Ma; Li et al, 2019), Wenquan (331 Ma; Jia, 2015), Wutuo (243 Ma; Dong, He, et al, 2018), and Aqikekulehu (Wu, Lan, Li, & Yu, 2001). Moreover, there are some E‐MOR type ophiolites distributed in Kekekete (509 Ma; Feng, 2010), Changshishan (537 Ma; Qi et al, 2016), and Qingshuiquan (516–436; Li et al, 2021; Ren et al, 2009).…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

Geochemistry, geochronology, and Hf isotope of diorites in the Marzheng area: Implications for the Early Palaeozoic tectonic evolution of the East Kunlun Orogenic Belt

et al. 2022

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The East Kunlun Orogenic Belt (E-KOB) of the northern Tibetan Plateau is an accretionary orogenic belt, which has experienced complicated tectonic evolutionary processes of the Proto-to Palaeo-Tethys Ocean. The Muztagh-Buqingshan-Anemaqen ophiolitic mélange zone (MBAM) is an accretionary complex related to the northward subduction of the Tethyan Ocean. Numerous intrusions outcropped in MBAM have witnessed the long-term subduction-accretionary process and thus site the key to comprehending the tectonic evolution of the E-KOB, as well as the Tethyan Ocean.In this study, petrological, geochronological, and geochemical studies of the Marzheng diorites in the MBAM were carried out to explore the Early Palaeozoic tectonic evolution of the E-KOB. Zircon U-Pb dating analysis suggests that the diorites were formed in the Early Ordovician at ca. 470 Ma. Furthermore, the ε Hf (t) values (5.3-14.1), Mg # values (39.7-51.2), and Nb/Ta (12.8-14.8), Zr/Hf (33.8-44.8), and Lu/Yb (0.15-0.16) ratios are generally close to those of depleted mantle-derived rocks and the diorites were originated from a depleted asthenosphere mantle source. In addition, these diorites are characterized by enriched light rare earth elements (LREEs) (La and Nd) and depleted high-field-strength elements (HFSEs) (Nb, Ta, P, and Ti), similar to the fingerprints of arc-related gabbroic-dioritic rocks. This is also consistent with their high H 2 O melt (6.0-8.3%) and oxygen fugacity (logfO 2 = À14.3 to À13.5) features, indicating that they were formed in a subduction-related setting. Our new investigations suggest that the Proto-Tethys Ocean in the East Kunlun was still actively subducting northward during the Early Ordovician.

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Section: Geological Setting and Samplesmentioning

confidence: 99%

Geochemistry, geochronology, and Hf isotope of diorites in the Marzheng area: Implications for the Early Palaeozoic tectonic evolution of the East Kunlun Orogenic Belt

et al. 2022

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“…Paleozoic ophiolites and related metamorphic units in the EKOB preserve a valuable record of the geodynamics of the northern Gondwana margin during the evolution of the Proto-Tethys Ocean [2]. Over the past decade, ophiolitic mélanges [3][4][5][6] and eclogites in the EKOB [7][8][9][10][11][12] have been targets for petrological and geochemical studies focused on understanding metamorphic histories and P-T paths. Results show that these metabasites record diverse Early Paleozoic high-to ultrahigh-pressure (HP-UHP) metamorphic conditions and thus provide an opportunity to understand the transition from subduction to continental collision within the Proto-Tethys domain [8][9][10]13].…”

Section: Introductionmentioning

confidence: 99%

Metabasites from the Central East Kunlun Orogenic Belt Inform a New Suture Model for Subduction and Collision in the Early Paleozoic Proto-Tethys Ocean

Chang,

Zhang,

Xiong

et al. 2024

Minerals

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The discovery of eclogite outcrops in the East Kunlun Orogen Belt (EKOB) has confirmed the existence of an Early Paleozoic HP-UHP metamorphic belt. However, the protoliths and metamorphic histories of widespread metabasites remain poorly constrained. We collected three types of metabasites from the central part of EKOB. We present an integrated study of petrography, whole-rock geochemistry, Sr-Nd isotopes, estimated P–T conditions, and zircon U-Pb isotope ages. The results show that amphibolites and retrograde eclogites have clockwise P–T paths with peak conditions of, respectively, 11–12 kbar and 675–695 °C, and 21.5–22.2 kbar and 715–750 °C. Zircon dating of metabasites from Dagele yields Late Ordovician (~449 Ma) to Early Silurian (~440 Ma) protolith ages and Early Devonian (~414 Ma) amphibolite facies metamorphic ages. Retrograde eclogites from east Nuomuhong have a protolith age of ~902 Ma and metamorphic ages of ~418 Ma, consistent with other eclogites from East Kunlun. Our data suggest that the protoliths of Dagele metabasites represent arc-type magmatism during the subduction of a small back-arc oceanic basin. Instead, the protoliths of retrograde eclogites are Neoproterozoic tholeiitic basalts emplaced into continental crust and subsequently deeply subducted. We develop a new model for Early Paleozoic subduction and collision in the East Kunlun region, emphasizing the role of ‘dominant’ and ‘secondary’ suture boundaries. This model helps explain the ages and metamorphic histories of the metabasites studied here and offers new perspectives on the evolution of the Proto-Tethys Ocean.

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“…Therefore, the existence of Dongkaco microcontinent became an on-going hot debate. Subduction-related ophiolites were produced under various tectonic environments in subduction zones, such as fore-arc (Reagan et al, 2010), arc (Ishimaru, Saikawa, Miura, Parlak, & Arai, 2018) and back-arc (Li, Pei, et al, 2019). These ophiolites generally display different geochemical characteristics (Pearce, 2008(Pearce, , 2014.…”

Section: Introductionmentioning

confidence: 99%

Geochemistry and geochronology of Pengco subduction‐related ophiolites, Tibet: Implications for Dongkaco microcontinent in the Bangong–Nujiang suture zone

Shao

Song

et al. 2021

Geological Journal

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The identification of a microcontinent in Bangong-Nujiang suture zone (BNSZ) is important to understanding the tectonic evolution of Bangong-Nujiang Tethys Ocean (BNTO). Subduction-related ophiolite is one of the keys to discriminate a microcontinent in suture zones, which can be generated during the oceanic subduction beneath the microcontinent. Generally, ophiolites in the adjacent area of a microcontinent would show characteristics of a volcanic arc, while ophiolites in adjacent area of an ocean show characteristics of a fore-arc. North Pengco ophiolites (NPOs) and South Pengco ophiolites (SPOs) were collected in the central section of BNSZ, and dated at 115.0-111.5 Ma by SHRIMP II. According to their trace element characteristics, NPOs were determined to have formed at a setting of subduction-related volcanic arc and affected by slab-derived fluids or melts. The diagram based on the Ce versus Ce/Y shows that NPOs originated from the partial melting of spinel peridotites. On the other hand, SPOs were generated from the partial melting of ultra-depleted mantle at a setting of subduction-related fore-arc on the basis of extraordinarily low REEs summation and HFSEs (e.g., Zr, Ti, Nb and Ta), relatively high concentrations of compatible elements (e.g., Cr, Ni), large ratios of CaO/TiO 2 (37.67-437.50) and Al 2 O 3 /TiO 2 (20.78-424.50), which were also affected by slab-derived fluids. Based on the relative location of NPOs and SPOs, it reasonably proposed that a northward subduction of a minor oceanic basin had occurred at the Early Cretaceous, trigged by the Dongkaco microcontinent (DMC). In reverse, these ophiolites provide evidence for the existence of DMC in BNTO. Combining with other subduction-related ophiolites developed in BNSZ, BNTO might have comprised of several minor oceanic basins separated by some blocks like DMC in the central and west sections, rather than a unified ocean basin.

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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

Cited by 25 publications

References 58 publications

Geochemistry, geochronology, and Hf isotope of diorites in the Marzheng area: Implications for the Early Palaeozoic tectonic evolution of the East Kunlun Orogenic Belt

Geochemistry, geochronology, and Hf isotope of diorites in the Marzheng area: Implications for the Early Palaeozoic tectonic evolution of the East Kunlun Orogenic Belt

Metabasites from the Central East Kunlun Orogenic Belt Inform a New Suture Model for Subduction and Collision in the Early Paleozoic Proto-Tethys Ocean

Geochemistry and geochronology of Pengco subduction‐related ophiolites, Tibet: Implications for Dongkaco microcontinent in the Bangong–Nujiang suture zone

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