Geochronology, geochemistry, and tectonic implications of early Neoproterozoic granitic rocks from the eastern Beishan Orogenic Belt, southern Central Asian Orogenic Belt

Wang, Biren; Yang, Xiao‐Song; Li, Shucai; Teng, Chao; Yang, Xinjie; Huang, Fuyong; Zhang, Xiaofei; Cao, Jian; Zhou, Yi; Zhang, Huachuan; Li, Jing

doi:10.1016/j.precamres.2020.106016

Cited by 14 publications

(5 citation statements)

References 52 publications

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“…Group III plutons of early episodic magmatism in the Dunhuang-Alxa Block (hereinafter referred to as Group III plutons) exhibit zircon U-Pb ages ranging from 929 Ma to 884 Ma, and are mainly composed of deformed two-mica granites, granitic gneiss, and mylonitized granite (Dan et al, 2014;Wang et al, 2021). These plutons of Group III contain peraluminous minerals, such as muscovite and tourmaline, consistent with their high A/CNK values (1.0-1.6, Fig.…”

Section: Group III Plutons: S-type Granitesmentioning

confidence: 88%

“…5b). In addition, Group III plutons exhibit high and constant P 2 O 5 contents (0.07-0.86 wt%, except one sample), which is different in comparison to the P 2 O 5 abundance of highly evolved peraluminous I-and A-type granites, but similar to those of the S-type granites (Dan et al, 2014;Wang et al, 2021). Thus, these Group III plutons can be classified as S-type granites.…”

Section: Group III Plutons: S-type Granitesmentioning

confidence: 89%

“…Group III plutons exhibit negative whole-rock ε Nd (t) values (−10.1 to −4.5), and highly variable zircon ε Hf (t) values (−6.2 to +3.8) with corresponding Hf model ages of 2160 Ma to 1544 Ma, which indicate that these Group III plutons originated from remelting of dominant (meta)sedimentary rocks with additions of mantle-derived melts (Dan et al, 2014;Wang et al, 2021).…”

Section: Group III Plutons: S-type Granitesmentioning

confidence: 99%

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A combination of plume and subduction tectonics contributing to breakup of northern Rodinia: Constraints from the Neoproterozoic magmatism in the Dunhuang-Alxa Block, northwest China

Zheng

Xiao

et al. 2022

GSA Bulletin

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Neoproterozoic igneous rocks are widely distributed in the Dunhuang-Alxa Block, northwest China, and record geodynamic processes caused by the assembly and break-up of Rodinia. In this study, we present new petrological, geochemical, and zircon U-Pb-Hf isotope data for the Langshan gabbros in the northeastern Alxa Block. Langshan gabbros (827−819 Ma) have depleted whole-rock Nd (+3.2 to +4.9) and zircon Hf (+4 to +21) isotopic compositions and weak enrichments in large-ion lithophile elements. These rocks were probably derived by partial melting of a depleted mantle wedge metasomatized by fluids released from a subducted slab in a back-arc basin environment. Geochemical and zircon Hf isotope data for early Neoproterozoic igneous rocks are consistent with the presence of a long-lived (ca. 930−810 Ma) retreating subduction zone along the northern margin of the Dunhuang-Alxa Block, indicating it was located at the northern margin of Rodinia. Some mantle plume-related magmatism, including A1-type silicic volcanic rocks in the Langshan Group and Jinchuan ultramafic-mafic intrusions, occurred in the interior of the Dunhuang-Alxa Block, which was similar to early Neoproterozoic plume-related magmatism (ca. 850−820 Ma) in the interior of northern Rodinia. The temporal link between subduction and extension suggests that this retreating subduction zone along the northern margin of Rodinia, in combination with a mantle plume beneath its interior, resulted in lithospheric extension and break-up of Rodinia during ca. 850−810 Ma.

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Section: Group III Plutons: S-type Granitesmentioning

confidence: 88%

Section: Group III Plutons: S-type Granitesmentioning

confidence: 89%

Section: Group III Plutons: S-type Granitesmentioning

confidence: 99%

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A combination of plume and subduction tectonics contributing to breakup of northern Rodinia: Constraints from the Neoproterozoic magmatism in the Dunhuang-Alxa Block, northwest China

Zheng

Xiao

et al. 2022

GSA Bulletin

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“…Some gneisses and granitoids exposed in the Jiujing region within the southern Beishan orogenic belt provided protolith intrusion ages of 1401–1450 Ma (He, Sun, et al, 2015; Yuan et al, 2019). Meanwhile, a series of gneissic granitoids and granitic gneisses exposed in the southern margin of southern Beishan orogenic belt provided protolith ages of 889–910 Ma, revealing the Neoproterozoic magmatic event (Figure 8; Jiang et al, 2013; Wang et al, 2021; Ye et al, 2013; Yuan et al, 2015). The Nd isotopic mapping of the Late Palaeozoic granitoids from the southern Beishan orogenic belt shows that these granitoids are characterized by variable ε Nd (t) values of 1.3 to −5.2 and old Nd model ages of 0.9–1.6 Ga (Figure 8 and 9b).…”

Section: Discussionmentioning

confidence: 99%

Discovery of a Mesoproterozoic granite in the northern Alxa Block and its tectonic implication

Shao

Niu

et al. 2022

Geological Journal

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A Mesoproterozoic granite covering about 5 km2 is firstly recognized in the Zhusileng area, which is located between the northern Alxa Block and the South Gobi microcontinent. New geochronological data from this area provide new insight for understanding the Precambrian crustal evolution of the middle segment of the southern Central Asian Orogenic Belt (CAOB). Based on the crystal shapes, internal textures, and high Th/U ratios, the zircons from this Mesoproterozoic granite are interpreted as magmatic origin. Meanwhile, LA‐ICP‐MS zircon U–Pb dating shows that it was emplaced at 1458 ± 7.5 Ma. Published geochronological data and Sr–Nd isotopic compositions of igneous rocks from the Zhusileng area and its vicinity are also compiled in this study. The Late Palaeozoic granitoids from the Zhusileng area have strongly negative εNd(t) values (−0.1 to −10.8), high (87Sr/86Sr)i (0.69657–0.73423) and old Nd model ages (0.9–1.8 Ga), suggesting the existence of Precambrian microcontinent in the Zhusileng area. Furthermore, the statistical analysis (or isotopic mapping) of Sr–Nd isotopic compositions of Palaeozoic granitoids from the middle segment of the southern CAOB also displays similar εNd(t) values and relatively old Nd model ages along the Hanshan Block, Zhusileng, Tsaggan Uul terrane, and Hutag Uul terrane. Therefore, we propose that those units may share a common basement during Mesoproterozoic to Early Neoproterozoic.

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“…It is a key area in the study of the tectonic evolution of the southern CAOB and the closure time of the PAO [15]. Four magmatic events occurred in the BOB [16]: Mesoproterozoic magmatic events representing the formation of an ancient basement in the Southern Beishan Orogenic Belt (SBOB) [17,18]; Neoproterozoic magmatism which represents the reworked ancient crust during the evolution of the Rodinia supercontinent [19,20]; Cambrian-Silurian arc magmatism related to the subduction of the Beishan ocean/PAO [21][22][23]; Ordovician-early late Paleozoic magmatic events correlating with the opening and closure of the branch of PAO [16,24], and the reference therein. Although a large number of late Paleozoic igneous rocks are distributed in the SBOB (Figure 1b), the formation environment of these magmatic rocks is still controversial (subduction, syn-collision or post collision) [12][13][14][25][26][27][28][29][30], which hampers the understanding of the final closure time of the PAO [12][13][14][25][26][27][28][29][30] and the tectonic evolution of the SBOB.…”

Section: Introductionmentioning

confidence: 99%

Early Permian Post-Collision Extensional Setting in the Southern Beishan Orogenic Belt: Evidence from the Zhangfangshan Granodiorite and the Baishantang Bimodal Volcanic Rocks

Wu,

Zhai,

Wang

et al. 2023

Minerals

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Outcrops of late Paleozoic magmatic rocks are common in the Southern Beishan Orogenic Belt (SBOB), Southern Central Asian Orogenic Belt (CAOB), which is a key object for the understanding of regional tectonism and defining the final closure time of the Paleo-Asian Ocean (PAO). We present zircon U-Pb chronology and whole-rock geochemistry data for late Paleozoic granodiorites and bimodal volcanic rocks from the Shuangyingshan-Huaniushan unit in the north Huitongshan-Zhangfangshan ophiolitic belt in the SBOB. The Zhangfangshan granodiorites (LA-ICP-MS, Ca. 288 Ma) are A2-type granite enriched in Rb, Th, Pb and LREEs and depleted in Nb, Ta, Ti, Sr, Ba and HREEs. They have varying MgO and TFe2O3 contents with high Mg# (38.56~48.97) values; the Lu/Yb ratios (0.14~0.15) of these granodiorites are similar to mantle-derived magma. A clear plagioclase zoning structure and acicular apatite occur in mineral assemblages derived from magma mixing between mafic and felsic magmas. The Baishantang bimodal volcanic rocks (272 Ma) consist of rhyolite and basaltic andesite. Baishantang rhyolites are A2-type felsic rock enriched in Rb, Th, Pb and LREEs and depleted in Nb, Ta, Ti, Sr, Ba and HREEs, with negative εNd(t) and εHf(t) (−5.2~−4.8 and −2.2~−1.9, respectively). Rhyolites originated from the partial melting of the crust, influenced by mantle material. Basaltic andesites belong to calc-alkaline series and have an enrichment of Rb, Ba, Th, U, Pb and LREEs, are weakly enriched in Zr-Hf, and are depleted in Nb, Ta, Ti and HREEs. The Nd-Hf isotopes of these basaltic andesites are not coupled with negative εNd(t) (−2.8~−0.4) and positive εHf(t) (1.8~5.5) values. These characteristics indicate that they originated from the partial melting of the mantle mixed with sediment-derived melts. In combination with previous studies, our findings show that the early Permian Zhangfangshan granodiorites and Baishantang bimodal volcanic rocks formed in a post-collision extensional setting, and the Huitongshan-Zhangfangshan ocean had been closed before early Permian.

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Geochronology, geochemistry, and tectonic implications of early Neoproterozoic granitic rocks from the eastern Beishan Orogenic Belt, southern Central Asian Orogenic Belt

Cited by 14 publications

References 52 publications

A combination of plume and subduction tectonics contributing to breakup of northern Rodinia: Constraints from the Neoproterozoic magmatism in the Dunhuang-Alxa Block, northwest China

A combination of plume and subduction tectonics contributing to breakup of northern Rodinia: Constraints from the Neoproterozoic magmatism in the Dunhuang-Alxa Block, northwest China

Discovery of a Mesoproterozoic granite in the northern Alxa Block and its tectonic implication

Early Permian Post-Collision Extensional Setting in the Southern Beishan Orogenic Belt: Evidence from the Zhangfangshan Granodiorite and the Baishantang Bimodal Volcanic Rocks

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