Petrogenesis and tectonic setting of the Middle Permian A-type granites in Altay, northwestern China: Evidences from geochronological, geochemical, and Hf isotopic studies

2017 ◽  
Vol 53 (2) ◽  
pp. 527-546 ◽  
Author(s):  
Yunlong Liu ◽  
Hui Zhang ◽  
Yong Tang ◽  
Xin Zhang ◽  
Zhenghang Lv ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Middle Permian ◽  
Northwestern China ◽  
Isotopic Studies

scholarly journals Permian Triassic geologic evolution in the southern Kitakami Belt, Japan

1992 ◽  
Vol 6 ◽  
pp. 155-155
Author(s):  
Kotaro Kamada
Keyword(s):  
Middle Triassic ◽  
Sedimentary Basin ◽  
Tectonic Setting ◽  
Japan Sea ◽  
Passive Margin ◽  
Middle Permian ◽  
Asian Continent ◽  
Transform Faults ◽  
Magmatic Arc ◽  
The Japan Sea

Before opening of the Japan Sea, the Japanese islands were attached to the eastern margin of the Asian continent. The Southern Kitakami Belt is regarded as a micro-continent in an accretional complex of the islands, that accreted before the Early Cretaceous. But its tectonic setting and location between the belt and the Asian continent is still an unresolved argument.Permo-Triassic sequences in the Southern Kitakami Belt are composed of shallow to off-shore deposits. These deposits are composed of clastics, carbonates with volcaniclastics. But there was no volcanic activity in the belt in the Middle to Late Permian. From the viewpoint of the sedimentary character and history, the Middle Permian to Middle Triassic sequences differ from their previous and their following successions in the belt. And the sedimentary basin of Middle Permian to Middle Triassic was bounded by transform faults. Magmatic arc was replaced by passive margin as hinterland of the Southern Kitakami Belt during the Middle Permian to Middle Triassic. It means that the sedimentary basin moved from the margin of Yangtze Platform to Sino-Korean Platform at that time.

Geochemistry, zircon geochronology, and isotopic systematics of the Zhanbuzhale granites in the East Kunlun, Qinghai Province, northwestern China: implications for the tectonic setting

2020 ◽  
Vol 57 (2) ◽  
pp. 275-291
Author(s):  
Hao-Ran Li ◽  
Ye Qian ◽  
Feng-Yue Sun ◽  
Liang Li
Keyword(s):  
Tectonic Setting ◽  
Alkali Feldspar ◽  
Northwestern China ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Qinghai Province ◽  
East Kunlun ◽  
Initial Stage ◽  
High K ◽  
Tethys Ocean

The Zhanbuzhale region, in the Eastern Kunlun Orogen of northwestern China, is characterized by large volumes of Phanerozoic granitoid rocks and is an ideal region for investigating the tectonic evolution of the Paleo-Tethys system. However, the exact timing of the final closure of the Paleo-Tethys Ocean and initial continental collision remains controversial because of a lack of precise geochronological and detailed geochemical data. In this paper, we report new zircon U–Pb ages and mineralogical, petrographic, and geochemical data for samples of Middle Triassic granodiorite and alkali feldspar granite from the Zhanbuzhale region. The zircon U–Pb ages indicate that the granodiorite and alkali feldspar granite formed at 239 and 236 Ma, respectively. The granodiorites are high-K calc-alkaline, metaluminous, high Sr content, high Sr/Y ratios, low Y content, and show adakite-like affinities. The alkali feldspar granites display high SiO2, extremely low MgO, and low Zr+Nb+Ce+Y contents as well as low Fe2O3t/MgO ratios, showing metaluminous to peraluminous and high-K calc-alkaline features. Geochemical and petrological characteristics of the alkali feldspar granites suggest that they are highly fractionated I-type granites. The granodiorites and alkali feldspar granites have zircon εHf(t) values ranging from –2.26 to –0.18, and from –2.17 to +2.18, respectively. Together with regional geological data, we propose that the Triassic (approximately 239–236 Ma) granitoids were generated during the later stages of northward subduction of the Paleo-Tethys oceanic plate, and that the initial stage of collision between the East Kunlun and the Bayan Har–Songpan Ganzi terrane occurred at approximately 236–227 Ma.

scholarly journals Tectonic Evolution of the West Bogeda: Evidences from Zircon U-Pb Geochronology and Geochemistry Proxies, NW China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 341
Author(s):  
Yalong Li ◽  
Wei Yue ◽  
Xun Yu ◽  
Xiangtong Huang ◽  
Zongquan Yao ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Tectonic Setting ◽  
Continental Rift ◽  
Middle Permian ◽  
Upper Permian ◽  
Late Permian ◽  
Island Arcs ◽  
The West ◽  
Structural Deformations ◽  
Tian Shan

The Bogeda Shan (Mountain) is in southern part of the Central Asian Orogenic Belt (CAOB) and well preserved Paleozoic stratigraphy, making it an ideal region to study the tectonic evolution of the CAOB. However, there is a long-standing debate on the tectonic setting and onset uplift of the Bogeda Shan. In this study, we report detrital zircon U-Pb geochronology and whole-rock geochemistry of the Permian sandstone samples, to decipher the provenance and tectonic evolution of the West Bogeda Shan. The Lower-Middle Permian sandstone is characterized by a dominant zircon peak age at 300–400 Ma, similar to the Carboniferous samples, suggesting their provenance inheritance and from North Tian Shan (NTS) and Yili-Central Tian Shan (YCTS). While the zircon record of the Upper Permian sandstone is characterized by two major age peaks at ca. 335 Ma and ca. 455 Ma, indicating the change of provenance after the Middle Permian and indicating the uplift of Bogeda Shan. The initial uplift of Bogeda Shan was also demonstrated by structural deformations and unconformity occurring at the end of Middle Permian. The bulk elemental geochemistry of sedimentary rocks in the West Bogeda Shan suggests the Lower-Middle Permian is mostly greywacke with mafic source dominance, and tectonic setting changed from the continental rift in the Early Permian to post rift in the Middle Permian. The Upper Permian mainly consists of litharenite and sublitharenite with mafic-intermediate provenances formed in continental island arcs. The combined evidences suggest the initial uplift of the Bogeda Shan occurred in the Late Permian, and three stages of mountain building include the continental rift, post-rift extensional depression, and continental arc from the Early, Middle, to Late Permian, respectively.

scholarly journals Varying Contents of Sources Affect Tectonic-Setting Discrimination of Sediments: A Case Study from Permian Sandstones in the Eastern Tianshan, Northwestern China

2017 ◽  
Vol 125 (3) ◽  
pp. 299-316 ◽  
Author(s):  
Xiaoran Zhang ◽  
Guochun Zhao ◽  
Paul R. Eizenhöfer ◽  
Min Sun ◽  
Yigui Han ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Northwestern China ◽  
Eastern Tianshan

Geochemistry of metasedimentary rocks of the Proterozoic Xingxingxia complex: implications for provenance and tectonic setting of the eastern segment of the Central Tianshan Tectonic Zone, northwestern China

2005 ◽  
Vol 42 (3) ◽  
pp. 287-306 ◽  
Author(s):  
Qiugen Li ◽  
Shuwen Liu ◽  
Baofu Han ◽  
Jian Zhang ◽  
Zhuyin Chu
Keyword(s):  
Tectonic Setting ◽  
Active Continental Margin ◽  
Northwestern China ◽  
Geochemical Data ◽  
Isotopic Study ◽  
Tectonic Zone ◽  
Elemental Ratios ◽  
Chemical Index ◽  
Eastern Segment ◽  
Chemical Index Of Alteration

The eastern segment of the Central Tianshan Tectonic Zone in northwestern China includes the Proterozoic metasedimentary Xingxingxia complex. Because these rocks have been extensively deformed and metamorphosed to greenschist or amphibolite facies, a geochemical and Nd isotopic study was undertaken to constrain their provenance and tectonic setting, as well as to evaluate the effects of weathering and sedimentary processes on the source rock signature. Major- and trace-element data indicate that these samples are characterized by negative Eu anomalies, low chemical index of alteration values, and high index of compositional variability values. Chemical index of alteration values and the plot of molecular proportions Al2O3–(CaO* + Na2O)–K2O suggest low degrees of weathering of the source. They are compositionally immature and poorly sorted. Geochemical data and immobile elemental ratios, for example Al2O3/TiO2, Cr/Th, Eu/Eu* and (La/Yb)n, indicate that the clastic materials were derived predominantly from felsic sources. Sedimentary tectonic discrimination diagrams demonstrate that most of the samples of the Xingxingxia complex were deposited on an active continental margin or continental island-arc setting. Rare-earth element distributions, εNd(t) values (calculated at 1.20 Ga, varying from –3.00 to +6.1), TDM model ages (ranging from 1.30 to 2.30), and t – εNd(t) plot, indicate that sediments of the Proterozoic Xingxingxia complex were derived from varying degrees of mixing between Paleoproterozoic crust and juvenile materials with the former predominating. There is an increased flux of juvenile materials from Weiya in the east through Dikar to Kumishi. The secondary juvenile source may be 1.2 Ga arc-magma materials.

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