Zircon SHRIMP U-Pb dating of granites from Dulan and the chronological framework of the North Qaidam UHP belt, NW China

Wu, Cailai; Gao, Yuanhong; Li, ZhaoLi; Lei, Min; Qin, Haipeng; Li, MinZe; Liu, Chunhua; Frost, Ronald B.; Robinson, Paul T.; Wooden, Joseph L.

doi:10.1007/s11430-014-4958-5

Cited by 68 publications

(36 citation statements)

References 37 publications

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“…Ague & Baxter, ; De Yoreo et al., ; Sandiford & Powell, ), although rare longer lived (>10 Ma) HT–LP metamorphism associated with coeval magmatism has been documented (Peressini, Quick, Sinigoi, Hofmann, & Fanning, ). Regionally, coeval mafic and granitic rocks with arc‐like compositional signatures are found in the South Qilian–North Qaidam orogenic belt (Fu, et al., ; Wu et al., , ; Yan et al., ; Zhu, Chen, Liu, & Li, ). These mafic and granitic intrusions have zircon crystallization ages of c .…”

Section: Discussionmentioning

confidence: 99%

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A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NWChina

Niu

Yakymchuk

et al. 2019

Journal Metamorphic Geology

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The early Palaeozoic South Qilian–North Qaidam orogenic belt in northwestern China records a nearly complete history of early‐stage long‐lived oceanic subduction–accretion followed by late‐stage continental collision. Most previous studies have focused on low dT/dP metamorphism (HP–UHP) in this belt whereas the paired high dT/dP belt in the hinterland has received little attention. In this contribution, phase equilibrium modelling is combined with zircon petrochronology to determine the P–T–t evolution of granulites in the North Wulan gneiss complex in the high dT/dP hinterland of the South Qilian–North Qaidam orogen. Granulites record a clockwise P–T path with near‐peak temperatures of ~800–900°C at 5.5–7 kbar. Peak metamorphism was followed by high‐T decompression. Zircon petrochronology reveals protracted zircon growth from c. 474 to 446 Ma during the high‐T portion of the P–T path. High dT/dP metamorphism in the North Wulan gneiss complex was likely the result of heat transfer from the underlying hot asthenosphere and minor coeval magmatism in an arc–back‐arc system during slab retreat and roll‐back of the South Qilian oceanic plate. Broadly contemporaneous but slightly younger HP–UHP metamorphism in the foreland of the South Qilian–North Qaidam orogenic belt indicates that the region records an early Palaeozoic paired metamorphic belt. This early Palaeozoic paired metamorphic belt provides a detailed example of dual thermal regimes in a modern‐style orogenic system that can be applied to understanding the time‐scales and P–T conditions of high dT/dP metamorphism that accompany subduction in Phanerozoic and Precambrian orogenic belts.

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Section: Discussionmentioning

confidence: 99%

“…These mafic and granitic intrusions have zircon crystallization ages of c . 470–445 Ma (Fu, et al., ; Wu et al., , ; Yan et al., ; Zhu et al., ), which are contemporaneous with c . 474–446 Ma HT–LP metamorphism in the North Wulan gneiss complex (Figures and ).…”

Section: Discussionmentioning

confidence: 99%

A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NWChina

Niu

Yakymchuk

et al. 2019

Journal Metamorphic Geology

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“…Partial melting also plays an important role in the geodynamics of continental subduction zones: It may result in crust–mantle interactions and even cause magmatism within subduction channels (Labrousse, Jolivet, Agard, Hébert, & Andersen, ; Labrousse, Prouteau, & Ganzhorn, ; Li, Chen, Zheng, Tang, & Hu, ; Song, Niu, Su, Wei, & Zhang, ; Zheng et al, ; Zheng & Hermann, ). Some syn‐collisional and post‐collisional magmatism has been identified within the Lüliangshan, Xitieshan, and Dulan terranes (Meng & Zhang, ; Song, Niu, Su, Wei, & Zhang, ; Wang, Song, Niu, & Su, ; Wu et al, ; Wu et al, ; Wu, Hanchar, et al, ; Wu, Wooden, et al, ; Wu, Zheng, et al, ; Zhao et al, ). Some syn‐collisional granite ages even overlap the peak age of ultrahigh‐pressure eclogite‐facies metamorphism (Meng & Zhang, ; Zhao et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that metamorphic zircon from different sources would have different Hf isotope compositions in an open system (Liu et al, ; Wu, Gao, et al, ; Zheng et al, ), while in a closed system metamorphic zircon could incorporate high 176 Hf/ 177 Hf(t) ratios from the breakdown of high Lu‐bearing major minerals (Amelin, Lee, & Halliday, ; Zheng et al, ) and low 176 Hf/ 177 Hf(t) ratios from the dissolution–reprecipitation of pre‐existing zircon (Wu, Gao, et al, ). The zircon REE pattern, in general, is also affected by the system type.…”

Section: Discussionmentioning

confidence: 99%

“…This may be attributable to either a high 176 Hf/ 177 Hf(t) ratio in the external melt that migrated in (Maki et al, ; Zeh & Gerdes, ) and/or the incorporation of radiogenic Hf from the breakdown of Lu‐bearing minerals (Zheng et al, ; Wu, Zheng, et al, ; Yang et al, ). In fact, due to the closed system, the high 176 Hf/ 176 Hf ratios in the metamorphic zircon core cannot have been caused by external melt but more likely incorporate Hf from high‐Hf internal minerals other than zircon (Wu, Gao, et al, ; Zheng et al, ). From the period of ca.…”

Section: Discussionmentioning

confidence: 99%

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Tracking the timing and nature of protolith, metamorphism, and partial melting of tourmaline‐bearing migmatites by zircon U–Pb and Hf isotopic compositions in the Yuka terrane, North Qaidam UHP metamorphic belt

Gao

Chen

et al. 2018

Geological Journal

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An integrated study using cathodoluminescence (CL) images, U–Pb geochronology, and Hf isotopic characterization of zircons was performed on migmatites from the Yuka terrane to provide insights into the timing and nature of the protoliths, metamorphism, and partial melting of these rocks. Zircon grains separated from the migmatites have three distinct domains. Residual zircon cores in samples YKT01 and YKT02 exhibit oscillatory zoning, high Th/U ratios (0.10–0.79), steep heavy rare earth element (HREE) patterns, and mean ages of 936 ± 5 Ma and 927 ± 11 Ma, respectively, indicating that they are igneous in origin and record Neoproterozoic magmatism during the Grenvillian Orogeny. CL‐grey cores record an ultrahigh‐pressure (UHP) peak metamorphism age of 435 ± 5 Ma and have low Th/U and 176Lu/177Hf ratios, weak negative Eu anomalies, and relatively flat HREE patterns. The CL‐bright rims have steep HREE patterns with lower middle rare earth element (MREE) concentrations but higher HREE concentrations compared with the metamorphic cores and a weighted average age of 422 ± 4 Ma, which records the timing of melt crystallization. The migmatites incorporate garnet relicts coexisting with fluid inclusions and hydrous minerals like peritectic phengite and peritectic large anhedral poikilitic tourmaline in the leucosomes. Peak temperatures are less than 750°C, suggesting that the anatectic melts may be derived from melting of felsic gneiss in the presence of water. The timing of melt crystallization is ca. 13 Ma later than UHP metamorphism, indicating that the partial melting took place during the exhumation stage. The metamorphic zircon cores have higher 176Hf/177Hf(t) ratios than the residual magmatic cores, which provides powerful evidence for the generation of the metamorphic zircons through the incorporation of internal high Hf minerals other than zircon in a closed system. Anatectic rims with lower 176Hf/177Hf(t) ratios but higher 176Lu/177Hf ratios than metamorphic cores suggest that the main formation mechanism is dissolution‐reprecipitation of pre‐existing zircons. In conclusion, the elevated 176Hf/177Hf(t), TDM2 age and decreasing 176Lu/177Hf(t) ratios in the metamorphic and anatectic domains imply that the new zircons in some migmatites and granites may not reflect the Hf isotope compositions of their source rocks, accounting for the variable Hf isotope compositions in S‐type granites.

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Geochronology and geochemistry of early‐middle Silurian intrusive rocks in the Lanzhou–Baiyin regions, eastern part of Qilian Block, NW China: Source and tectonic implications

Zhao

et al. 2017

Geological Journal

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The Qilian Block is one of many continental blocks involved in the early Paleozoic orogenesis of the Central China Orogen, which experienced complex interaction with adjacent blocks and orogens. In this study, we present zircon U–Pb–Hf isotopic, whole‐rock elemental, and Sr–Nd isotopic data of the early‐middle Silurian intrusive rocks in the Lanzhou–Baiyin regions, eastern part of the Qilian Block, to constrain their source and tectonic settings. The Houchangchuan granodiorite and Shichuan monzogranite were emplaced at ca. 437 Ma and ca. 428 Ma, respectively. These granitoids are peraluminous (A/CNK = 1.1–1.3), enriched in LREEs and LILEs (Rb, Th, U, Pb), depleted in HFSEs (Nb, Ta) with negative Eu and Sr anomalies, and have relatively high whole‐rock εNd(t), −4.3 to −2.1, and zircon εHf(t), −10.9 to 1.1, values. The Shichuan monzonite is characterized by intermediate SiO2, metaluminous (A/CNK = ~0.8), and high LREEs fractionation with LILEs (Th, U, Pb) enrichment and HFSEs (Nb, Ta) depletion. We suggest the Houchangchuan granodiorite and Shichuan monzogranite were derived from the metasedimentary (metapelitic) source, which could be the Mesoproterozoic basement of the Qilian Block, and the mantle‐derived materials injected into their source region. The Shichuan monzonite could have a mantle‐derived origin. Integrated with data from previous studies, the early‐middle Silurian (437–428 Ma) intrusive rocks in the eastern part of the Qilian Block were formed during the transition period from a syn‐collisional to postcollisional setting, relating to the collisional process after the consumption of North Qilian Ocean (Proto‐Tethys Ocean) in the northern margin of the Gondwana continent.

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Zircon SHRIMP U-Pb dating of granites from Dulan and the chronological framework of the North Qaidam UHP belt, NW China

Cited by 68 publications

References 37 publications

A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NWChina

A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NWChina

Tracking the timing and nature of protolith, metamorphism, and partial melting of tourmaline‐bearing migmatites by zircon U–Pb and Hf isotopic compositions in the Yuka terrane, North Qaidam UHP metamorphic belt

Geochronology and geochemistry of early‐middle Silurian intrusive rocks in the Lanzhou–Baiyin regions, eastern part of Qilian Block, NW China: Source and tectonic implications

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