scholarly journals Petrogenesis of Early Paleozoic high Sr/Y intrusive rocks from the North Qilian orogen: Implication for diachronous continental collision

Lithosphere ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 53-73 ◽  
Author(s):  
He Yang ◽  
Hongfei Zhang ◽  
Wenjiao Xiao ◽  
Biji Luo ◽  
Zhong Gao ◽  
...  
Keyword(s):  
Crustal Thickness ◽  
Crustal Thickening ◽  
Geochemical Data ◽  
Thickness Variation ◽  
Early Paleozoic ◽  
Isotopic Data ◽  
Differential Distribution ◽  
The North ◽  
Qilian Orogen ◽  
North Qilian

Abstract A combination of U-Pb zircon ages and geochemical and Sr-Nd-Hf isotopic data are presented for the Early Paleozoic granodiorites from the Haoquangou and Baimawa plutons in order to probe the crustal thickness variation of the eastern North Qilian and the diachronous evolution of the North Qilian orogen. The granodiorites formed at 436–435 Ma and have high Sr/Y ratios (63–117). Elemental and isotopic data combined with geochemical modeling and comparisons with experimental data suggest that they were produced from the melting of relatively juvenile mafic rocks in the thickened lower crust. Together with other petrological and geochemical data and the calculation of variation in crustal thickness, this indicates that the eastern North Qilian experienced clear crustal thickening and thinning from the Late Ordovician to Late Silurian. Based on available data, we suggest that diachronous collision from east to west, which probably resulted in the distinct intensity of orogenesis between eastern and western North Qilian, can well account for the differential distribution of Early Paleozoic high Sr/Y magmatism and other geological differences between the eastern and western parts of the North Qilian. Our study also implies that diachronous collision may lead to, apart from distinct metamorphic, structural and sedimentary responses, the large differences in magmatism and deep crustal processes along the orogenic strike.

Integrated analyses constraining the provenance of sandstones, mudstones, and conglomerates, a case study: the Laojunshan conglomerate, Qilian orogen, northwest China

2007 ◽  
Vol 44 (7) ◽  
pp. 961-986 ◽  
Author(s):  
Zhen Yan ◽  
Wenjiao Xiao ◽  
Zongqi Wang ◽  
Jilian Li
Keyword(s):  
Tibetan Plateau ◽  
Middle Devonian ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Geochemical Data ◽  
The North ◽  
Northern Tibetan Plateau ◽  
Wide Range ◽  
Qilian Orogen ◽  
North Qilian

The Qilian orogenic belt in the northern Tibetan plateau connects the Altaids to the north with the Tethyan orogenic system to the south and occupies a key tectonic position in the evolution and assembly of Asia. The belt contains a wide range of subduction–accretion-related petrotectonic units. The Early–Middle Devonian Laojunshan conglomerate, deposited unconformably upon Cambrian–Silurian strata along the northern margin of the North Qilian terrane, contains a record of the late Paleozoic tectonism of the Qilian orogen. Its provenance and tectonic setting are critical in understanding not only the tectonic evolution of Tibetan plateau, but Paleozoic global reconstructions as well. The composition of clastic conglomerates and heavy mineral assemblages of sandstones suggests that coeval mafic, felsic, metamorphic, and sedimentary rocks were the main sources. The geochemistry of volcanic clasts and paleocurrent and paleogeographic data suggest derivation from subduction–accretion complexes in the North Qilian terrane. The geochemistry of siltstones and mudstones indicates that the Laojunshan conglomerate was derived from an arc and accumulated in an active continental margin. Geochemical data of granitoid clasts suggest that they were derived from Ordovician–Silurian subduction-related magmatic rocks. Mafic and ultramafic clasts, chromite, and magnetite decrease upwards in the stratigraphy whereas metamorphic, sedimentary and granitoid clasts, and garnet increase. These data imply that mafic rocks were the predominant source during initial deposition. Regional studies suggest that the North China plate subducted southwards and produced subduction-related arc magmatism along the southern margin of the North Qilian terrane during the Early–Middle Devonian. Therefore, we interpret the Laojunshan conglomerate as a fore-arc basin fill.

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

scholarly journals On the origin of mafic magmatic enclaves (MMEs) in syn-collisional granitoids: evidence from the Baojishan pluton in the North Qilian Orogen, China

2015 ◽  
Vol 109 (5) ◽  
pp. 577-596 ◽  
Author(s):  
Shuo Chen ◽  
Yaoling Niu ◽  
Wenli Sun ◽  
Yu Zhang ◽  
Jiyong Li ◽  
...  
Keyword(s):  
The North ◽  
Magmatic Enclaves ◽  
Qilian Orogen ◽  
North Qilian

scholarly journals Crustal thickness of the Grenville orogen: A Mesoproterozoic Tibet?

Geology ◽  
2021 ◽  
Author(s):  
Adam Brudner ◽  
Hehe Jiang ◽  
Xu Chu ◽  
Ming Tang
Keyword(s):  
Crustal Thickness ◽  
Detrital Zircons ◽  
Crustal Thickening ◽  
Geochemical Data ◽  
Geochronological Data ◽  
Grenville Province ◽  
Crustal Thinning ◽  
Paleoenvironmental Evolution ◽  
Orogenic Plateau ◽  
St Lawrence River

The Grenville Province on the eastern margin of Laurentia is a remnant of a Mesoproterozoic orogenic plateau that comprised the core of the ancient supercontinent Rodinia. As a protracted Himalayan-style orogen, its orogenic history is vital to understanding Mesoproterozoic tectonics and paleoenvironmental evolution. In this study, we compared two geochemical proxies for crustal thickness: whole-rock [La/Yb]N ratios of intermediate-to-felsic rocks and europium anomalies (Eu/Eu*) in detrital zircons. We compiled whole-rock geochemical data from 124 plutons in the Laurentian Grenville Province and collected trace-element and geochronological data from detrital zircons from the Ottawa and St. Lawrence River (Canada) watersheds. Both proxies showed several episodes of crustal thickening and thinning during Grenvillian orogenesis. The thickest crust developed in the Ottawan phase (~60 km at ca. 1080 Ma and ca. 1045 Ma), when the collision culminated, but it was still up to 20 km thinner than modern Tibet. We speculate that a hot crust and several episodes of crustal thinning prevented the Grenville hinterland from forming a high Tibet-like plateau, possibly due to enhanced asthenosphere-lithosphere interactions in response to a warm mantle beneath a long-lived supercontinent, Nuna-Rodinia.

Finding of Neoproterozoic (∼775 Ma) magmatism recorded in metamorphic complexes from the North Qilian orogen: Evidence from SHRIMP zircon U-Pb dating

2006 ◽  
Vol 51 (8) ◽  
pp. 963-970 ◽  
Author(s):  
Chien-Yuan Tseng ◽  
Houng-Yi Yang ◽  
Wan Yusheng ◽  
Liu Dunyi ◽  
Da-Jen Wen ◽  
...  
Keyword(s):  
The North ◽  
Qilian Orogen ◽  
Shrimp Zircon ◽  
North Qilian ◽  
Metamorphic Complexes

Compositional and Sr–Nd–Hf isotopic variations of Baijingsi eclogites from the North Qilian orogen, China: Causes, protolith origins, and tectonic implications

2015 ◽  
Vol 28 (2) ◽  
pp. 721-734 ◽  
Author(s):  
Choon-Muar Ker ◽  
Huai-Jen Yang ◽  
Jianxin Zhang ◽  
Yen-Hong Shau ◽  
Chia-Ju Chieh ◽  
...  
Keyword(s):  
The North ◽  
Tectonic Implications ◽  
Qilian Orogen ◽  
Isotopic Variations ◽  
North Qilian

Cambrian magmatic flare-up, central Tibet: Magma mixing in proto-Tethyan arc along north Gondwanan margin

2021 ◽  
Author(s):  
Pei-yuan Hu ◽  
Qing-guo Zhai ◽  
Peter A. Cawood ◽  
Guo-chun Zhao ◽  
Jun Wang ◽  
...  
Keyword(s):  
Magma Mixing ◽  
Geochemical Data ◽  
Early Paleozoic ◽  
East African ◽  
Lhasa Terrane ◽  
The North ◽  
Magmatic Rocks ◽  
East African Orogen ◽  
Andean Type ◽  
Central Tibet

Accompanying Gondwana assembly, widespread but diachronous Ediacaran−early Paleozoic magmatism of uncertain origin occurred along the supercontinent’s proto-Tethyan margin. We report new geochemical, isotopic, and geochronological data for Cambrian magmatic rocks (ca. 500 Ma) from the Gondwana-derived North Lhasa terrane, located in the present-day central Tibetan Plateau. The magmatic rocks are composed of basalts, gabbros, quartz monzonites, granitoids (with mafic microgranular enclaves), and rhyolites. Nd-Hf isotopic and whole-rock geochemical data indicate that these rocks were probably generated by mixing of mantle-derived mafic and crust-derived felsic melts. The mantle end-member volumes of mafic, intermediate, and felsic rocks are ∼75%−100%, 50%−60%, and 0−30%, respectively. Integration of our new data with previous studies suggests that the North Lhasa terrane experienced long-term magmatism through the Ediacaran to Ordovician (ca. 572−483 Ma), with a magmatic flare-up at ca. 500 Ma. This magmatism, in combination with other Ediacaran−early Paleozoic magmatism along the proto-Tethyan margin, was related to an Andean-type arc, with the magmatic flare-up event related to detachment of the oceanic slab following collisional accretion of Asian microcontinental fragments to northern Gondwana. Diachroneity of the proto-Tethyan arc system along the northern Gondwanan margin (ca. 581−531 Ma along the Arabian margin and ca. 512−429 Ma along the Indian-Australian margin) may have been linked to orogenesis within Gondwana. The North Lhasa terrane was probably involved in both Arabian and Indian-Australian proto-Tethyan Andean-type orogens, based on its paleogeographic location at the northern end of the East African orogen.

Partial melting of thickened lower crust in post‐collisional setting: Evidence from high silicon adakitic granites in the North Qilian orogen

2019 ◽  
Vol 55 (5) ◽  
pp. 3990-4007
Author(s):  
Yun‐shuai Li ◽  
Liang‐jia Xu ◽  
Sheng‐yao Yu ◽  
Jian‐xin Zhang ◽  
Jing Guo ◽  
...  
Keyword(s):  
Partial Melting ◽  
Lower Crust ◽  
The North ◽  
High Silicon ◽  
Qilian Orogen ◽  
North Qilian
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