Age and petrogenesis of late Paleozoic granites from the northernmost Alxa region, northwest China, and implications for the tectonic evolution of the region

Zhang, Wen; Pease, Victoria; Meng, Qingpeng; Zheng, Rongguo; Wu, Taotao; Chen, Yan; Gan, Lisheng

doi:10.1007/s00531-016-1297-0

Cited by 33 publications

(29 citation statements)

References 47 publications

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“…However, no evidence, such as tectonic deformation, magmatic activity or the sedimentary record, supports the northward subduction of the PAO represented by the Enger Us ophiolitic belt. Therefore, we conclude that the southward subduction of the PAO represented by the Yagan Fault Belt, which is located to the north of the study area and represents an important boundary according to the comparable lithologies on the southern and northern flanks of the boundary (Zhang et al 2017;Liu et al 2018), occurred during late Palaeozoic time and was responsible for the late Palaeozoic volcanic activity in the northern ZHTZ.…”

Section: C Tectonic Implications For the Northern Alxa Areamentioning

confidence: 81%

“…Three major fault belts have been recognized in the Alxa area, which are termed, from north to south, the Yagan Fault Belt, the Enger Us Fault Belt and the Quagan Qulu Fault Belt (also called the Badain Jaran Fault) (Wu & He, 1993). The Yagan Fault Belt has been suggested to represent an important boundary according to the comparable lithology of the southern and northern flanks of the boundary (Zhang et al 2017;Liu et al 2018). An ophiolitic mélange belt is exposed along the Enger Us Fault Belt, which is generally regarded as a major suture zone separating the CAOB to the north from the North China Craton to the south (Wang et al 1994).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Some authors suggested an active continental margin setting (Wu et al 1998;Liu et al 2018), whereas others argued for a postcollisional setting (Dang et al 2011;Zheng et al 2013;Zhang et al 2017;Fei et al 2019). This controversy partly results from insufficient petrogenetic constraints on the coeval mafic magmatic rocks that are more sensitive in defining key phases of tectonic environments compared to felsic rocks.…”

Section: B1 the Gabbrosmentioning

confidence: 99%

“…As a result, the region was transformed into an active continental margin during late Palaeozoic time (Wu et al 1998;Zheng et al 2013). Based on the geochemical and geochronological characteristics of the magmatic rocks exposed in the northern Alxa area, some authors argued that the late Palaeozoic volcanic activity in this region was related to the northward subduction of the PAO represented by the Enger Us ophiolitic belt (Liu et al 2016(Liu et al , 2017Zhang et al 2017). The Enger Us ophiolitic belt is widely accepted to represent the major suture of the PAO in the Alxa area, and the Quagan Qulu ophiolitic belt represents a back-arc basin.…”

Section: C Tectonic Implications For the Northern Alxa Areamentioning

confidence: 99%

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Early Permian to Late Triassic tectonics of the southern Central Asian Orogenic Belt: geochronological and geochemical constraints from gabbros and granites in the northern Alxa area, NW China

Zhang

Shi

et al. 2020

Geol. Mag.

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Situated between the North China Craton to the east and the Tarim Craton to the west, the northern Alxa area in westernmost Inner Mongolia in China occupies a key location for interpreting the late-stage tectonic evolution of the southern Central Asian Orogenic Belt. New LA-ICP-MS zircon U–Pb dating results reveal 282.2 ± 3.9 Ma gabbros and 216.3 ± 3.2 Ma granites from the Yagan metamorphic core complex in northern Alxa, NW China. The gabbros are characterized by low contents of Si, Na, K, Ti and P and high contents of Mg, Ca, Al and Fe. These gabbros have arc geochemical signatures with relative enrichments in large ion lithophile elements and depletions in high field strength elements, as well as negative εNd(t) (−0.91 to −0.54) and positive εHf(t) (2.59 to 6.37) values. These features indicate that a depleted mantle magma source metasomatized by subduction fluids/melts and contaminated by crustal materials was involved in the processes of magma migration and emplacement. The granites show high-K calc-alkaline and metaluminous to weakly peraluminous affinities, similar to A-type granites. They have positive εNd(t) (1.55 to 1.99) and εHf(t) (5.03 to 7.64) values. These features suggest that the granites were derived from the mixing of mantle and crustal sources and formed in a postcollisional tectonic setting. Considering previous studies, we infer that the final closure of the Palaeo-Asian Ocean in the central part of the southern Central Asian Orogenic Belt occurred in late Permian to Early–Middle Triassic times.

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Section: C Tectonic Implications For the Northern Alxa Areamentioning

confidence: 81%

Section: Geological Backgroundmentioning

confidence: 99%

Section: B1 the Gabbrosmentioning

confidence: 99%

Section: C Tectonic Implications For the Northern Alxa Areamentioning

confidence: 99%

See 2 more Smart Citations

Early Permian to Late Triassic tectonics of the southern Central Asian Orogenic Belt: geochronological and geochemical constraints from gabbros and granites in the northern Alxa area, NW China

Zhang

Shi

et al. 2020

Geol. Mag.

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“…Triassic terrestrial sediments consisting of conglomerate and sandstone are locally distributed. Late Palaeozoic plutons are intermediate to felsic in composition with ages from ~383 to ~283 Ma (Zhang et al, ). Mesozoic granites are locally distributed along this zone.…”

Section: Geological Settingmentioning

confidence: 99%

LateCarboniferous–earlyPermian arc magmatism in the south‐westernAlxaTectonicBelt (NW China):Constraints on the latePalaeozoic subduction history of thePalaeo‐AsianOcean

et al. 2018

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The tectonic setting of the Alxa Tectonic Belt (ATB) during the late Palaeozoic is highly controversial. The nature and tectonic origin of the late Palaeozoic magmatism in the ATB are key to resolving the current controversy. This paper provides field, petrographic, geochemical, and zircon U‐Pb‐Hf isotopic data for the late Palaeozoic granitoids and volcanic rocks from the south‐western ATB. The granitoids display a wide range of SiO2 contents from diorite, granodiorite, to granites, with widely distributed hydrous minerals such as hornblende and biotite. They are calc‐alkaline to high‐potassium calc‐alkaline, metaluminous with an enrichment of light rare earth elements and large‐ion lithophile elements (LILE), and a depletion of high‐field‐strength elements (HFSE). The presence of mafic‐intermediate enclaves in the plutons suggests the role of crust–mantle interaction in generating the granitoids. The volcanic rocks show “block‐in‐matrix” structures in the field. They are dacite‐porphyry and rhyolite and show calc‐alkaline characteristics with an enrichment of LILE and a depletion of HFSE. Laser ablation inductively coupled plasma mass spectrometry zircon U‐Pb dating shows that the granitoids and enclaves crystallized during ~317–287 Ma and the dacite porphyry formed at ~295 Ma. Hf‐in‐zircon isotopic compositions reveal predominately positive εHf (t) values and Neoproterozoic TDMC ages for the magmatic rocks, indicating mixing between mantle‐derived magma and Precambrian basement during their genesis. The diagnostic field, geochemical data, and isotopic data imply these rocks were generated in a subduction‐related active continental margin setting. The presence of A2‐type granite indicates an extensional environment resulted from slab rollback in a retreating accretionary context can best interpret the large‐scale late Carboniferous–early Permian magmatism in the ATB. Our new data, combined with published data, imply that a large active continental margin existed in the Beishan, Alxa, and the northern margin of the North China Craton, due to the south‐dipping subduction of the Palaeo‐Asian Ocean (PAO) in the late Palaeozoic. Therefore, our data suggest that the PAO did not close until after the early Permian.

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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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Age and petrogenesis of late Paleozoic granites from the northernmost Alxa region, northwest China, and implications for the tectonic evolution of the region

Cited by 33 publications

References 47 publications

Early Permian to Late Triassic tectonics of the southern Central Asian Orogenic Belt: geochronological and geochemical constraints from gabbros and granites in the northern Alxa area, NW China

Early Permian to Late Triassic tectonics of the southern Central Asian Orogenic Belt: geochronological and geochemical constraints from gabbros and granites in the northern Alxa area, NW China

LateCarboniferous–earlyPermian arc magmatism in the south‐westernAlxaTectonicBelt (NW China):Constraints on the latePalaeozoic subduction history of thePalaeo‐AsianOcean

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

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