Petrogenesis of Early Silurian granitoids in the Longshoushan area and their implications for the extensional environment of the North Qilian Orogenic Belt, China

Wang, Kaixing; Yu, Chi-Da; Yan, Jie; Liu, Xiaodong; Liu, Wenheng; Pan, Jiayong

doi:10.1016/j.lithos.2019.05.029

Cited by 23 publications

(19 citation statements)

References 65 publications

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“…However, the fresh host-granitoids in the Jiling uranium deposit were metaluminous to peraluminous without magmatic uraninite [30]. The chemical ages of the BP uraninite varied from 426 Ma to 445 Ma as discussed above, which is similar to the age range of crystallization of the granitoid intrusions in the area around the Jiling uranium deposit (from 427 to 441 Ma, U-Pb isotopic system on zircons by LA-ICP-MS) [30]. These age similarities together with the elevated REE, Th, and Y contents in the uraninite, and the weak fractionation of the whole REE patterns (Supplementary Materials B) are all in favor of a crystallization of the uraninite in the Jiling uranium deposit from magmatic-hydrothermal fluid.…”

Section: Origin Of Uranium Mineralizationmentioning

confidence: 98%

“…It is connected with the Northern Qilian orogenic belt to the south and the Chaoshui Basin to the north. The Altyn-Tagh Fault, a huge left slip strike-slip fault, cuts the western part of the LMB, and the Tarim Craton adjacent to the west part of the LMB ( Figure 1B) [9,[26][27][28][29][30].…”

Section: The Longshoushan Uranium Metallogenetic Belt (Lmb)mentioning

confidence: 99%

“…The NW-trending Jiling complex intrudes into the Proterozoic strata, with a length of 54 km and a width of two to three kilometers, representing an exposed area of 160 km 2 . The Jiling complex is composed of diorite, granite, syenite, and acidic and basic dikes [8,10,14,27,29,30,34,43]. The granitoids in the Jiling complex are mainly composed of medium to coarse-grained gray quartz monzonite and granodiorite (441 ± 14 Ma) [30], medium-coarse grained fleshy red granodiorite and granite (441 ± 15 Ma) [30], fine-grained granite (442 ± 6 Ma) [38], and syenite (427.2 ± 3.6 Ma) [26].…”

Section: The Jiling Uranium Depositmentioning

confidence: 99%

“…Uraninite occurs mainly in high fractionated peraluminous leucogranite and related pegmatites, such as the granites host hydrothermal-vein-type uranium deposit in South China [57,58], high-Ca metaluminous granites, low-Ca peraluminous granites, peralkaline granites, and in weakly peraluminous anatectic pegmatoids resulting from a low degree of partial melting of metasedimentary rocks [59,60]. However, the fresh host-granitoids in the Jiling uranium deposit were metaluminous to peraluminous without magmatic uraninite [30]. The chemical ages of the BP uraninite varied from 426 Ma to 445 Ma as discussed above, which is similar to the age range of crystallization of the granitoid intrusions in the area around the Jiling uranium deposit (from 427 to 441 Ma, U-Pb isotopic system on zircons by LA-ICP-MS) [30].…”

Section: Origin Of Uranium Mineralizationmentioning

confidence: 99%

“…During the Paleozoic, during the transition from a compressional to an extensional tectonic regime, an upwelling asthenospheric mantle heated up the lithospheric, and induced the generation of mafic and felsic magmas [30]. Granitoids and syenite were formed with different ratios of mixing between the felsic and mafic magmas.…”

Section: Uranium Mineralization Processmentioning

confidence: 99%

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Uranium Mineralogical and Chemical Features of the Na-Metasomatic Type Uranium Deposit in the Longshoushan Metallogenic Belt, Northwestern China

Wang

Liu

et al. 2020

Minerals

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The Longshoushan Metallogenic Belt (northwestern China) is known for its word-class Jinchuan Ni-Cu sulfide (Pt) deposit and is also an important uranium metallogenic belt. The Jiling uranium deposit in this belt is a typical Na-metasomatic uranium deposit, which rarely occurs in China. Mineralization in the Jiling uranium deposit is hosted in granitoids that have suffered a Na-metasomatic alteration. There are three kinds of uranium minerals, including uraninite, pitchblende, and coffinite in the Jiling uranium deposit. Pitchblende is the predominant uranium mineral. Integrating the mineralogy and geochemistry of uranium minerals, and in situ electron microprobe analyzer (EMPA) U-Th-Pb chemical dating, we aimed to unravel the age and nature of the mineralization, to decipher the characteristics of the hydrothermal alteration and the U mineralization process. Based on the microtextural features and compositional variations, primary uraninite was altered to uraninite A and B, and fresh pitchblende was altered to pitchblende A and B. The best-preserved uraninite crystals displayed a euhedral-shape with high Pb and low SiO2, CaO, FeO, and Al2O3 contents, and was interpreted as primary uraninite. The EMPA U-Th-Pb chemical ages revealed that uraninite may have formed at 435.9 ± 3.3 Ma. High ThO2 + ΣREE2O3 + Y2O3 contents illustrated that the best preserved uraninite crystallized at a high temperature. Altered pitchblende A showed a relatively brighter gray color in backscattered electron (BSE) images and with a lower SiO2 content than B. Three analysis spots of the fresh pitchblende showed low contents of ΣSiO2 + CaO, indicating no obvious alteration. EMPA U-Th-Pb chemical dating gave a mean chemical age of 361 Ma. The low Th + ΣREE2O3 contents indicated that this pitchblende formed at a relatively low temperature. According to the different characteristics of occurrence and chemical composition, the coffinite in the Jiling uranium deposit can be divided into coffinite A and B, respectively. The compositional variation of the fresh and altered uraninite and pitchblende indicated that both uraninite and pitchblende underwent at least two discrete hydrothermal fluid alterations. The U mineralization was divided into two stages; uraninite was formed at a high temperature and possibly from a magmatic-hydrothermal fluid during ore stage I. Then, pitchblende was formed at a low temperature, during ore stage II. According to the petrographic observations and their chemical compositions, coffinite A and B resulted from the alterations of uraninite and pitchblende, respectively.

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Section: Origin Of Uranium Mineralizationmentioning

confidence: 98%

Section: The Longshoushan Uranium Metallogenetic Belt (Lmb)mentioning

confidence: 99%

Section: The Jiling Uranium Depositmentioning

confidence: 99%

Section: Origin Of Uranium Mineralizationmentioning

confidence: 99%

Section: Uranium Mineralization Processmentioning

confidence: 99%

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Uranium Mineralogical and Chemical Features of the Na-Metasomatic Type Uranium Deposit in the Longshoushan Metallogenic Belt, Northwestern China

Wang

Liu

et al. 2020

Minerals

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Magma mixing in the genesis of the Qingshanbao granitoids in the Longshoushan area: Implications for the tectonic evolution of the North Qilian orogenic belt, NW China

et al. 2021

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The geochemical differences of magmatic rocks can be influenced by melt source and magmatic processes, including partial melting, fractional crystallization and magma mixing. New whole‐rock geochemical analyses, zircon U–Pb ages and Hf‐isotope data on granitoids from the Qingshanbao complex in the Longshoushan belt highlight a significant Late Ordovician–Early Silurian magmatic episode during the collision between the Alxa and Qilian‐Qaidam blocks, in which magma mixing was a fundamental process. The Qingshanbao complex comprises K‐feldspar granite, granodiorite and diorite emplaced coevally from 442 to 433 Ma. They exhibit peraluminous to metaluminous I‐type features, are enriched in large‐ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in high‐field‐strength elements (HFSEs). Chondrite‐normalized REE patterns are fractionated (LaN/YbN = 10.2–34.9) with weakly negative Eu anomalies (Eu/Eu* = 0.66–0.94). The 176Lu/177Hf zircon two‐stage model ages (TDM2) and the εHf(t) on zircons extracted from the K‐feldspar granite (1613–2,316 Ma, εHf(t) = −14.4 to −3.0) and granodiorite (1640–2015 Ma, εHf(t) = −9.6 to −3.6) suggest they were formed by the mixing of melts produced by the melting of Mesoproterozoic crustal materials, most likely meta‐basic rocks from the Longshoushan Group, and to a lesser extent mantle materials. In contrast, zircons in the diorite yield TDM2 ages ranging from 964 to 1767 Ma and εHf(t) values of −5.5 to 7.1, implying melting of depleted mantle rocks with subordinate participation of lower crust materials. We suggest that the Qingshanbao complex was emplaced when the North Qilian area was in a transitional stage from a compressional to an extensional environment as early as approximately 442 Ma.

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Palaeozoic tectonic transition of the North Qilian Belt in the northern margin of the Tibetan Plateau, NW China: Insights from detrital zircon U–Pb geochronology and sedimentology

et al. 2021

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This study presents new integrated stratigraphic, sedimentary, and geochronological data for Silurian to Devonian sedimentary rocks in the central North Qilian Belt (NQB), NW China. These data constrain the timing and processes involved in the Palaeozoic tectonic transition from compression to extension in the NQB. This study indicates that the Angzanggou Formation probably formed in a foreland basin setting during 439-430 Ma compression associated with the closure of the North Qilian Ocean. The terrestrial sedimentary rocks overlying the formation were most likely deposited in a superimposed basin at 409-388 Ma as a result of the post-orogenic extension of the NQB, an event that involved initial post-orogenic extension-related sedimentation. Silurian-Devonian sediments were derived from multiple sources, including the NQB, Central Qilian Block (CQB), and Alxa and Dunhuang blocks. Convergence between the CQB and the Alxa Block propagated westward, leading to the scissor-like closure of the North Qilian Ocean during the Middle to Late Silurian and the oblique docking and collision of these two blocks. This is evidenced by a lack of middle-upper Silurian sedimentary rocks in the middle and eastern NQB compared with the well-developed and well-preserved sedimentary strata in the western segment. Devonian retrogradation and intracontinental extension-related magmatism in the NQB also provide evidence of long-lived tectonic extension of the lithosphere.Combining these new data with previously published data for the NQB and the wider region suggests that the Devonian terrestrial strata were deposited in a postorogenic extensional setting similar to that in the North Qaidam and East Kunlun belts, indicating that the Palaeozoic large-scale tectonic transition from compression to extension in these three belts most likely started during the Early Devonian.

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Petrogenesis of Early Silurian granitoids in the Longshoushan area and their implications for the extensional environment of the North Qilian Orogenic Belt, China

Cited by 23 publications

References 65 publications

Uranium Mineralogical and Chemical Features of the Na-Metasomatic Type Uranium Deposit in the Longshoushan Metallogenic Belt, Northwestern China

Uranium Mineralogical and Chemical Features of the Na-Metasomatic Type Uranium Deposit in the Longshoushan Metallogenic Belt, Northwestern China

Magma mixing in the genesis of the Qingshanbao granitoids in the Longshoushan area: Implications for the tectonic evolution of the North Qilian orogenic belt, NW China

Palaeozoic tectonic transition of the North Qilian Belt in the northern margin of the Tibetan Plateau, NW China: Insights from detrital zircon U–Pb geochronology and sedimentology

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