Paleozoic multi-stage accretionary evolution of the SW Chinese Tianshan: New constraints from plutonic complex in the Nalati Range

Zhong, Linglin; Wang, Bo; Алексеев, Д. В.; Cao, Yuchuang; Biske, Yu. S.; Liu, Huan; Zhai, Yong‐Ping; Xing, Langzhang

doi:10.1016/j.gr.2016.12.012

Cited by 53 publications

(41 citation statements)

References 126 publications

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“…According to the vergence of structures along the STS, to the east of the Talas Ferghana Fault, extrusion of the HPMU was accommodated by a basal (top‐to‐the‐north) thrust and an upper (top‐to‐the‐south) detachment (Figure b), which suggests that the subduction of the Turkestan Ocean was south‐dipping (e.g., Charvet et al., ; Loury et al., ). This south‐dipping subduction is also suggested by the opening of back‐arc basins along the N‐Tarim margin (upper plate) at 334–309 Ma (Wang et al., ; Zhong et al., ). In contrast, to the west of the Talas Ferghana Fault, a nappe stack includes c .…”

Section: Geological Settingmentioning

confidence: 73%

Tectonometamorphic evolution of the Atbashi high‐Punits (KyrgyzCAOB, Tien Shan): Implications for the closure of the Turkestan Ocean and continental subduction–exhumation of the South Kazakh continental margin

Loury

Rolland

Guillot

et al. 2018

Journal Metamorphic Geology

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The South Tien Shan (STS) belt results from the last collision event in the western Central Asian Orogenic Belt (CAOB). Understanding its formation is of prime importance in the general framework of the CAOB. The Atbashi Range preserves high‐P (HP) rocks along the STS suture, but still, its global metamorphic evolution remains poorly constrained. Several HP units have been identified: (a) a HP tectonic mélange including boudins of mafic eclogites in a sedimentary matrix, (b) a large (>100 km long) high‐P metasedimentary unit (HPMU) and (c) a lower blueschist facies accretionary prism. Raman Spectroscopy on carbonaceous material combined with phengite and chlorite multiequilibria and isochemical phase diagram modelling indicates that the HPMU recorded homogeneous P–T conditions of 23–25 kbar and 560–570°C along the whole unit. 40Ar/39Ar dating on phengite from the HPMU ranges between 328 and 319 Ma at regional scale. These ages are interpreted as (re‐) crystallization ages of phengite during Tmax conditions at a pressure range of 20–25 kbar. Thermobarometry on samples from the HP tectonic mélange provides similar metamorphic peak conditions. Thermobarometry on the blueschist to lower greenschist facies accretionary prism indicates that it underwent P–T conditions of 5–6 kbar and 290–340°C, highlighting a 17–20 kbar pressure gap between the HPMU‐tectonic mélange units and the accretionary prism. Comparison with available geochronological data suggests a very short time span between the prograde path (340 Ma), HP metamorphic peak (330 Ma), the Tmax (328–319 Ma) and the final exhumation of the HPMU (303–295 Ma). Extrusion of the HPMU, accommodated by a basal thrust and an upper detachment, was driven by buoyant forces from 70–75 km up to 60 km depth, which directly followed continental subduction and detachment of the HPMU. At crustal depths, extrusion was controlled by collisional tectonics up to shallow levels. Lithological homogeneity of the HPMU and its continental‐derived character from the North Tien Shan suggest this unit corresponds to the hyper‐extended continental margin of the Kazakh continent, subducted southward below the north continental active margin of the Tarim craton. Integration of the available geological data allows us to propose a general geodynamic scenario for Tien Shan during the Carboniferous with a combination of (a) N‐dipping subduction below the Kazakh margin of Middle Tien Shan until 390–340 Ma and (b) S‐dipping subduction of remaining Turkestan marginal basins between 340 and 320 Ma.

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Section: Geological Settingmentioning

confidence: 73%

Tectonometamorphic evolution of the Atbashi high‐Punits (KyrgyzCAOB, Tien Shan): Implications for the closure of the Turkestan Ocean and continental subduction–exhumation of the South Kazakh continental margin

Loury

Rolland

Guillot

et al. 2018

Journal Metamorphic Geology

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“…(b) A southward subduction model (e.g., Charvet et al, ; B. Chen et al, ; Loury et al, ; Wang et al, ). This is supported by arc‐type magmatic rocks in the STOB (Guo et al, ; Lin et al, ; Zhong et al, ; Z. X. Zhu et al, ) and top‐to‐the‐north ductile deformation in metamorphic rocks and ophiolitic mélanges (Charvet et al, ; Lin et al, ; Wang et al, ). Moreover, (c) a double‐sided subduction was proposed by Gao, Long, et al () and T. Jiang et al () through integrating the above geological characteristics.…”

Section: Implications For the Tectonic Evolution Of The Stobmentioning

confidence: 93%

“…The South Tianshan Orogenic Belt (STOB) is located north of the Tarim Craton and the southwest margin of the CAOB and is characterized by the distribution of ophiolitic mélanges and metamorphic rocks (Figure b). Although some progress has been achieved in the past decades (e.g., Gao, Long, et al, ; Gao, Qian, et al, ; Gao et al, ; B. F. Han, He, Wang, & Guo, ; Huang et al, ; Klemd, John, Scherer, Rondenay, & Gao, ; Wang, Shu, Charvet, Faure, & Ma, ; Zhang, Ai, Li, et al, ; Zhang, Ai, Song, Liou, & Wei, ; Zhong et al, ), controversy still exists regarding the geodynamic setting of the South Tianshan Ocean, the subduction polarity of ocean closure, and the time of the collision. Some authors thought that there was only one single broad basin that is continuously subducted (C. Chen, Lu, Jia, Cai, & Wu, ; Gao, Li, Xiao, Tang, & He, ; Long et al, ; Xiao et al, ).…”

Section: Introductionmentioning

confidence: 99%

Accreted seamounts in the South Tianshan Orogenic Belt, NW China

Yang

et al. 2018

Geological Journal

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The South Tianshan Orogenic Belt (STOB) is situated in the southwest margin of the Central Asian Orogenic Belt and is characterized by the distribution of ophiolitic mélanges and metamorphic rocks. In this study, we focus on 5 ophiolitic mélanges with ocean island basalt (OIB) and aim to discuss the tectonic evolution of the South Tianshan Ocean. The Kynda, Kainar, Uchkel, Heiyingshan, and Guluogou ophiolitic mélanges in STOB mainly consist of metamorphic peridotite, gabbros, basaltic lavas (pillows), abyssal radiolarian cherts, and limestones. The basaltic rocks mainly occur as tectonic blocks within the mélanges. These basaltic rocks are characterized by LREE enrichment and HREE depletion, very weak or no Eu anomalies, and no obvious Nb, Ta, and Ti negative anomalies, positive εNd(t) values, relatively high initial 87Sr/86Sr ratios, and wide 206Pb/204Pb ratios, showing the signature of OIB. The OIB‐type rocks from Kynda, Kainar, and Guluogou are likely to be derived from garnet lherzolite by relatively high degrees of melting (10% to 20%). But the basaltic rocks of Uchkel and Heiyingshan formed at significantly lower degrees of partial melting (1% to 5%) of spinel and/or garnet lherzolite. The OIB‐type rocks in these ophiolitic mélanges are considered as accreted seamount fragments and may represent mantle plume‐related magmatism within the South Tianshan Ocean. In combination with previous work, we suggest an updated model, which is bidirectional oceanic subduction with seamounts accretion and subduction system, is suitable for Palaeozoic tectonic evolution of the South Tianshan Ocean.

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“…Permian formations include the Early Permian bimodal volcanic rocks, and the Middle to Late Permian molasse deposition uncomfortably overlying the pre‐Permian rocks (He, Zhang, Wang, Qian, & Sun, ; Wang et al, ). Voluminous Ordovician‐Permian granitoids intrusions on both sides of the Yili Block (Figure 1b) were interpreted to be related to the subduction of the Junggar and/or South Tianshan oceans beneath the Yili Block (Huang et al, ; Long et al, ; Su et al, ; Wang et al, ; Xu et al, ; Zhong et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

“…Ordovician-Permian granitoids intrusions on both sides of the Yili Block ( Figure 1b) were interpreted to be related to the subduction of the Junggar and/or South Tianshan oceans beneath the Yili Block (Huang et al, 2013;Long et al, 2011;Su et al, 2018;Wang et al, 2012;Xu et al, 2013;Zhong et al, 2017).…”

Section: Voluminousmentioning

confidence: 99%

Volcanic–plutonic connection and associated Au‐Cu mineralization of the Tulasu ore district, Western Tianshan, NW China: Implications for mineralization potential in Palaeozoic arc terranes

et al. 2020

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Constructing the plutonic–volcanic connections in volcanic arc setting is essential for understanding a variety of magmatic processes from continental crust differentiation to formation of magmatic‐hydrothermal ore deposits. Based on the combination of zircon U–Pb geochronology and Hf isotope and whole‐rock geochemistry and Sr‐Nd isotopes, we evaluated the potential connections between volcanic and plutonic rocks from the Tulasu Basin, the largest epithermal gold ore district in the Chinese Western Tianshan. The peak of volcanism coincides well with the major plutonism, representing an important magma event at ~347–367 Ma. These contemporaneous volcanic and plutonic rocks show broadly similar arc‐related geochemical signatures and zircon in‐situ Hf (εHf[t] = −1.0–14.3) and whole‐rock Nd (εNd[t] = −4.2–4.6) isotopic compositions, indicative of formation from parental magmas derived from a common depleted mantle source metasomatized by slab‐derived melts, despite diverse consequent processes (fractional crystallization, crustal contamination, and magma mixing/mingling) during their differentiation in a subduction‐related setting. Volcanic rocks from the Axi caldera in the centre of the Tulasu district are geochemically less evolved than the coeval porphyritic granite, which indicates that the intrusive rocks might originate from residual melts left behind by extraction of erupted magmas. In contrast, the porphyry Cu mineralized Kexiaxi pluton, which occurs in the margin of the Tulasu district, is compositionally indistinguishable from the coeval volcanic suites. This implies that the Kexiaxi pluton represents the intrusive equivalent of a common magma reservoir feeding the volcanic eruptions, and magma fluxes may have controlled their differentiation. We thus suggest that the depleted mantle derived calc‐alkaline magma, modified during slab‐related melt metasomatism, crustal contamination, and magma mixing may have played an important role in copper enrichment at Kexiaxi. Finally, the relatively water‐rich and fertile nature of arc magma of the Tulasu district indicates high exploration potential for significant porphyry Cu‐Au deposits. The existing alteration‐immobile fertility proxy (V/Sc) for intrusive rocks may also be useful to assess the fertility of cogenetic volcanic rocks, in turn with implications for unexposed porphyry Cu deposits at depths.

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Paleozoic multi-stage accretionary evolution of the SW Chinese Tianshan: New constraints from plutonic complex in the Nalati Range

Cited by 53 publications

References 126 publications

Tectonometamorphic evolution of the Atbashi high‐Punits (KyrgyzCAOB, Tien Shan): Implications for the closure of the Turkestan Ocean and continental subduction–exhumation of the South Kazakh continental margin

Tectonometamorphic evolution of the Atbashi high‐Punits (KyrgyzCAOB, Tien Shan): Implications for the closure of the Turkestan Ocean and continental subduction–exhumation of the South Kazakh continental margin

Accreted seamounts in the South Tianshan Orogenic Belt, NW China

Volcanic–plutonic connection and associated Au‐Cu mineralization of the Tulasu ore district, Western Tianshan, NW China: Implications for mineralization potential in Palaeozoic arc terranes

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