The timing of Barleik Formation and its implication for the Devonian tectonic evolution of Western Junggar, NW China

2021 ◽  
Vol 13 (1) ◽  
pp. 188-196
Author(s):  
Yuanxiu Hui ◽  
Ran Wang ◽  
Lu Li ◽  
Jingyu Lin ◽  
Zhouxuan Xiao ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Sedimentary Environment ◽  
Weighted Average ◽  
Island Arc ◽  
Late Devonian ◽  
Adjacent Area ◽  
Nw China ◽  
Icp Ms ◽  
Invertebrate Fossils ◽  
Tectonic Belt

Abstract The timing of Barleik Formation in Xinjiang, NW China, has not been constrained by accurate geochronology yet, while this work is of great significance to help reconstruct the geological tectonic evolution of Western Junggar. Based on the LA-ICP-MS U–Pb geochronology study, the weighted average age of magmatic zircons collected from the tuff in Barleik Formation, which reflects the formation age of the tuff, is 372 ± 2 Ma (N = 57, mean square of weighted deviates (MSWD) = 1.15). The first report in this study of the zircon U–Pb dating result indicates that Barleik Formation along the West Junggar tectonic belt occurred in the Late Devonian rather than in the middle Devonian period as previously claimed. Meanwhile, chronology data and the geochemical features comparing with the Island Arc-related rocks in the adjacent area, as well as stratigraphic structural relationship, suggest that volcanic activities may exist in the Late Devonian, and the relevant volcanic ash deposited in the Barleik forearc basin may be derived from the adjacent island arc (current geographic coordinate). In addition, the fossil assemblage dominated by bathyal-abyssal invertebrate fossils and bathyal-abyssal facies indicates that the Barleik Formation is a bathyal-abyssal sedimentary environment.

The tectonic evolution of the Irtysh tectonic belt: New zircon U–Pb ages of arc-related and collisional granitoids in the Kalaxiangar tectonic belt, NW China

Lithos ◽  
2017 ◽  
Vol 272-273 ◽  
pp. 46-68 ◽  
Author(s):  
Tao Hong ◽  
Reiner Klemd ◽  
Jun Gao ◽  
Peng Xiang ◽  
Xing-Wang Xu ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Nw China ◽  
Tectonic Belt

Permian to Triassic tectonic evolution of the Alxa Tectonic Belt, NW China: Constraints from petrogenesis and geochronology of felsic intrusions

Lithos ◽  
2021 ◽  
Vol 384-385 ◽  
pp. 105980
Author(s):  
Fenquan Xie ◽  
Jinghua Wu ◽  
Yonghe Sun ◽  
Lidong Wang ◽  
Jizhong Wu ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Nw China ◽  
Tectonic Belt

The Liuyuan complex in the Beishan, NW China: a Carboniferous–Permian ophiolitic fore-arc sliver in the southern Altaids

2011 ◽  
Vol 149 (3) ◽  
pp. 483-506 ◽  
Author(s):  
QIGUI MAO ◽  
WENJIAO XIAO ◽  
BRIAN F. WINDLEY ◽  
CHUNMING HAN ◽  
JUNFENG QU ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Weighted Average ◽  
Geochemical Data ◽  
Current Debate ◽  
Mafic Rocks ◽  
Nw China ◽  
Tectonic History ◽  
Icp Ms ◽  
Ocean Ridge ◽  
Basic Rocks

AbstractThe tectonic history and time of closure of the Palaeo-Asian ocean of the Altaids are issues of lively current debate. To address these issues, this paper presents detailed geological, petrological and geochemical data of the Liuyuan complex (LC) in the Beishan region in NW China, located in the southernmost Altaids, in order to constrain its age, origin and tectonic setting. The LC mainly comprises massive basalts, pillow basalts, basaltic breccias, gabbros and ultramafic rocks together with cherts and tuffs. Most prominent are gabbros and large volumes of basaltic lavas. These mafic rocks have high TiO2 contents, flat rare earth element (REE) patterns and show high-field-strength elements (HFSEs) similar to those of mid-ocean ridge basalts (MORB). The mafic rocks exhibit positive εNd(t) (6.6–9.0) values, representing magmas derived from the mantle. But these basic rocks are also enriched in Th relative to REEs, and are systematically depleted in Nb–Ta–(Ti) relative to REEs. There is also a large range in initial 87Sr/86Sr (0.7037–0.7093). All these variables indicate that mantle-derived magma was contaminated by fluids and/or melts from a subducting lithospheric slab, and formed in a supra-subduction zone (SSZ) setting. A gabbro intruded in the complex was dated by LA-ICP-MS on 20 zircons that yielded a 206Pb–238U weighted average age of 286 ± 2 Ma. Considering the fact that all these basalts are imbricated against Permian tuffaceous sediments and limestone, we propose that the LC formed as an ophiolite in a fore-arc in Carboniferous–Permian time. This indicates that the Palaeo-Asian ocean still existed at 286 ± 2 Ma in early Permian time, and thus the time of closure of the Palaeo-Asian ocean was in or after the late Permian.

scholarly journals Volcanism and intrusive magmatism of the Magnitogorsk paleoarc in the epoch of its “soft” collision with a margin of the East European continent

LITOSFERA ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 630-651
Author(s):  
D. N. Salikhov ◽  
V. V. Kholodnov ◽  
V. N. Puchkov ◽  
I. R. Rakhimov
Keyword(s):  
Chemical Elements ◽  
Early Carboniferous ◽  
Island Arc ◽  
Late Devonian ◽  
European Continent ◽  
East European ◽  
Icp Ms ◽  
Mantle Sources ◽  
Spatial Isolation ◽  
Academy Of Sciences

Research subject. The article sets out to investigate the change of the geodynamic regime from the island-arc type to the accretionary-collisional type in the Late Devonian–Early Carboniferous, which occurred as a result of 1) a collision between the Western part of the Magnitogorsk island arc and the Eastern margin of the East European continent and 2) its later coupling with the heterogeneous composite East Uralian terrain.Materials and methods. The content of petrogenic elements and microelements in the rocks of the Late Paleozoic island-arc complexes of the Magnitogorsk island arc were determined using XRF and ICP MS methods at the Laboratory of Physicochemical Research Methods of the Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences. In addition, available publications on the composition and formation conditions of these complexes were reviewed.Results. It was found that, in the Late Devonian–Early Carboniferous period, the process of island-arc magmatism of the Magnitogorsk paleoarc was substituted with the formation of intraplate volcano-intrusive complexes. The island-arc magmageneration and its manifestations were controlled by a latitudinal linear zoning and different depths of formation of magmatic cameras, reflecting the self-consistency and spatial isolation of these events.Conclusion. Due to the intensifying collision, melts from different mantle sources were mixing, thus contaminating the island-arc rocks by intraplate (plume-dependent) magmas. According to the composition and concentrations of high-field strength and fluid-mobile chemical elements, suprasubductional fluids played an important role in the evolution of late-island arc magmatic series.

Petrogenesis and tectonic evolution of the Palaeozoic to Mesozoic Niuxinshan granitoids in the North Qilian orogen, NW China

2021 ◽  
Author(s):  
Fan Yang ◽  
Fei Xue ◽  
M. Santosh ◽  
Zesheng Qian ◽  
Cun Zhang ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Nw China ◽  
The North ◽  
Qilian Orogen ◽  
North Qilian

Geochemical characteristics and geologic significance of rare earth elements in oil shale of the Yan’an Formation in the Tanshan area, in the Liupanshan Basin, China

2021 ◽  
pp. 1-41
Author(s):  
Lianfu Hai ◽  
Qinghai Xu ◽  
Caixia Mu ◽  
Rui Tao ◽  
Lei Wang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Oil Shale ◽  
Sedimentary Environment ◽  
Moderate Degree ◽  
Material Source ◽  
Icp Ms ◽  
Ree Distribution ◽  
Heavy Rare Earth Elements ◽  
Degree Of Differentiation

In the Tanshan area, which is at the Liupanshui Basin, abundant oil shale resources are associated with coals. We analyzed the cores, geochemistry of rare earth elements (REE) and trace element of oil shale with ICP-MS technology to define the palaeo-sedimentary environment, material source and geological significance of oil shale in this area. The results of the summed compositions of REE, and the total REE contents (SREE), in the Yan'an Formation oil shale are slightly higher than the global average of the composition of the upper continental crustal (UCC) and are lower than that of North American shales. The REE distribution pattern is characterized by right-inclined enrichment of light rare earth elements (LREE) and relative loss of heavy rare earth elements (HREE), which reflects the characteristics of crustal source deposition. There is a moderate degree of differentiation among LREE, while the differences among HREE are not obvious. The dEu values show a weak negative anomaly and the dCe values show no anomaly, which are generally consistent with the distribution of REE in the upper crust. The characteristics of REE and trace elements indicate that the oil shale formed in an oxygen-poor reducing environment and that the paleoclimatic conditions were relatively warm and humid. The degree of differentiation of REE indicates that the sedimentation rate in the study area was low, which reflected the characteristics of relatively deep sedimentary water bodies and distant source areas. The results also proved that the source rock mainly consisted of calcareous mudstone, and a small amount of granite was also mixed in.

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