Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China

Meng, Fanwei; Zhang, Jianxin

doi:10.1007/s11434-009-0205-4

Cited by 13 publications

(5 citation statements)

References 29 publications

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“…For instance, the Xitieshan granite (ca. 441 Ma) (Zhao et al, 2017); Tuanyushan granitoids (444 ± 4 Ma) (Wu et al, 2009); Da Qaidam granites (446 ± 4 Ma) (Wu et al, 2007), and Lüliangshan granites (430 ± 8 Ma) (Meng and Zhang, 2009) provide strong evidence that they formed in a syn-collisional setting.…”

Section: Tectonic Setting and Implicationsmentioning

confidence: 99%

Geochemistry and Zircon U‐Pb Geochronology of Early Paleozoic S‐type Granites in the Eastern Qilian Block, Northwest China

Liu

Han

et al. 2021

Acta Geologica Sinica (Eng)

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The importance of granitoids in understanding the evolutionary history of a geological terrane has attracted petrologists to study the granitoids in the QB. However, the generation of the early Paleozoic magmatism and tectonic evolution of the QO are controversial. Previous researchers advocated that this orogeny was associated with the southward subduction of the North Qilian lithosphere beneath the QB and subsequent collision (

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Section: Tectonic Setting and Implicationsmentioning

confidence: 99%

Geochemistry and Zircon U‐Pb Geochronology of Early Paleozoic S‐type Granites in the Eastern Qilian Block, Northwest China

Liu

Han

et al. 2021

Acta Geologica Sinica (Eng)

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“…Distribution of metamorphic ages for the four terranes in the North Qaidam UHP metamorphic belt. Data are from Chen et al 2008Chen et al , 2009Meng and Zhang 2009;Mattinson et al 2006Mattinson et al , 2009Song et al 2003aSong et al , 2005bSong et al , 2006Song et al , 2011Xiong et al 2010;Yang et al 2005;Zhang, G.B. et al 2008aZhang, G.B.…”

Section: Relationship Between the Xitieshan Terrane And The Other Termentioning

confidence: 99%

First record and timing of UHP metamorphism from zircon in the Xitieshan terrane: Implications for the evolution of the entire North Qaidam metamorphic belt

Liu

Gao

et al. 2012

American Mineralogist

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The Xitieshan terrane is one of four metamorphic terranes in the North Qaidam metamorphic belt, which is an early Paleozoic high-pressure to ultrahigh-pressure (HP-UHP) metamorphic belt in NW China. However, conclusive evidence and precise timing of UHP metamorphism in the Xitieshan terrane have not been well documented. In this study, we report an integrated study of zircon grains from an amphibolite in the Xitieshan terrane in terms of mineral inclusions, trace elements, and U-Pb age systematics. The first record of coesite is reported as an inclusion in a metamorphic zircon, which provides unambiguous evidence for the UHP metamorphism of the Xitieshan terrane. The metamorphic zircon domains have weak or no zoning, very low Th/U ratios, insignificant Eu anomalies, and flat HREE patterns. Zircon grains contain inclusions of garnet, omphacite and rutile, in addition to the coesite inclusion. These inclusions indicate that the metamorphic zircon grains formed under UHP metamorphic conditions. The metamorphic zircon grains were dated by the SIMS and LA-ICPMS methods and yield weighted mean ages of 432 ± 14 and 441 ± 9 Ma, respectively. Combined with previous results, the HP-UHP metamorphism of the Xitieshan terrane may have lasted 460-440 Ma with the peak UHP metamorphism at 441 ± 9 Ma. A compilation of the reported geochronological data reveals that all four terranes of the North Qaidam metamorphic belt might have experienced coeval UHP metamorphism during the early Paleozoic (420-450 Ma), and thus may have suffered a coherent subduction, UHP metamorphism, and exhumation cycle.

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“…Zircon is absent in primitive peridotites due to unsaturation of both Zr and Si. , However, abundant zircon grains have been reported from peridotites (e.g., Griffin et al, 2000;Grieco et al, 2001;Zheng et al, 2003;Song et al, 2005Song et al, , 2009Zhang et al, 2005;Meng and Zhang, 2009;Liu et al, 2010). High modal content of magmatic zircons have been observed in garnet peridotite in Alaskan-type ultramafic cumulate intrusions (Song et al, 2005(Song et al, , 2009.…”

Section: Origin Of Group I Zircon and Formation Environment Of The Myanmar Jadeititementioning

confidence: 99%

“…High modal content of magmatic zircons have been observed in garnet peridotite in Alaskan-type ultramafic cumulate intrusions (Song et al, 2005(Song et al, , 2009. Zircon has also been found in melt/fluid-metasomatised mantle peridotites (e.g., Grieco et al, 2001;Meng and Zhang, 2009;Liu et al, 2010). Shervais (2008) reported that the Elder Creek ophiolite contains almost all of the components of a classic ophiolite (mantle tectonites, cumulate ultramafics and gabbro, dyke complex, volcanics), and has substantial volumes (25%-30% of the complex) of felsic plutonic rocks intimately associated with the other lithologies; the latter rocks crystallised abundant zircons.…”

Section: Origin Of Group I Zircon and Formation Environment Of The Myanmar Jadeititementioning

confidence: 99%

Trace element features of hydrothermal and inherited igneous zircon grains in mantle wedge environment: A case study from the Myanmar jadeitite

Lei

Shi

Santosh

et al. 2016

Lithos

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channel presumably from the overlying mantle wedge, and therefore zircons from these rocks provide important insights into mantle wedge processes. Here we investigate hydrothermal zircon (Group II) formed within a subduction zone and compare these with the igneous zircon cores (Group I) from the Myanmar jadeitite.Previous U-Pb studies reported ages of Group I and II zircons as ~163 Ma, and ~147 Ma respectively, and both show isotope signature of the depleted mantle. Group I zircons have much higher total concentrations of rare earth elements (REEs) (500 -1945 ppm) than those of Group II zircon (112 -307 ppm), and contains relatively higher abundance of Y, Nb, Ta, Ti, Th and U with higher (Sm/La) N ratios (25.3 -501) and Ce-anomalies (8.04 -140) but lower (Yb/Gd) N ratios (9.76 -57.0) than those of the Group II ( (Sm/La) N ratios = 2.12 -32.2, Ce-anomalies = 1.63 -19.6, (Yb/Gd) N ratios = 44.8 -142). Hf concentrations are broadly similar in both Groups. The Group I zircons are considered to be magmatic and crystallised from H 2 O-rich basaltic melt at relatively high pressure in the mantle wedge, whereas the Group II zircon overgrowth took place through recrystallisation and precipitation with distinct dissolution of the Group I zircons. Variation in the concentration of trace elements in zircons from Group I to II in the mantle wedge is related to an intra-oceanic subduction system in the presence of Na-rich hydrothermal fluids under high-pressure and low-temperature. The Ti-in-zircon thermometer yield a mean crystallisation 3 temperature of 742 ± 141ºC for Group I zircons, whereas the Group II zircons yields 339 ± 33ºC. The two groups of zircons also provide insights into the probable protolith involved in formation of the Myanmar jadeitite.

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Genesis of the mega-crystal zircons in the dunite veins of North Qaidam Mountains, northwestern China

Cited by 13 publications

References 29 publications

Geochemistry and Zircon U‐Pb Geochronology of Early Paleozoic S‐type Granites in the Eastern Qilian Block, Northwest China

Geochemistry and Zircon U‐Pb Geochronology of Early Paleozoic S‐type Granites in the Eastern Qilian Block, Northwest China

First record and timing of UHP metamorphism from zircon in the Xitieshan terrane: Implications for the evolution of the entire North Qaidam metamorphic belt

Trace element features of hydrothermal and inherited igneous zircon grains in mantle wedge environment: A case study from the Myanmar jadeitite

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