Anatexis of former arc magmatic rocks during oceanic subduction: A case study from the North Wulan gneiss complex

Li, Xiucai; Niu, Manlan; Yakymchuk, Chris; Yan, Zhen; Fu, Changlei; Zhao, Qida

doi:10.1016/j.gr.2018.04.016

Cited by 38 publications

(19 citation statements)

References 98 publications

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“…The Hf isotope trends of these metamorphic rims lie within the evolution trend of the 3.0 Ga tonalitic rocks (Fig. 8b), which implies that the Hf incorporated into metamorphic zircon was likely sourced from the dissolution of pre-existing zircon during anatexis, with no breakdown of radiogenic phases, or little time between growth and breakdown (e.g., Flowerdew et al 2006;Li et al 2018). We link these metamorphic events to the thermal events associated with magmatic accretion as recorded in the coeval minor magmatism.…”

Section: Later Magmatic and Metamorphic Eventsmentioning

confidence: 60%

Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

Gardiner

Kirkland

Hollis

et al. 2019

Contrib Mineral Petrol

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Constraining the source, genesis, and evolution of Archaean felsic crust is key to understanding the growth and stabilization of cratons. The Akia Terrane, part of the North Atlantic Craton, West Greenland, is comprised of Meso-to-Neoarchaean orthogneiss, with associated supracrustal rocks. We report zircon U-Pb and Lu-Hf isotope data, and whole-rock geochemistry, from samples of gneiss and supracrustals from the northern Akia Terrane, including from the Finnefjeld Orthogneiss Complex, which has recently been interpreted as an impact structure. Isotope data record two major episodes of continental crust production at ca. 3.2 and 3.0 Ga. Minor ca. 2.7 and 2.5 Ga magmatic events have more evolved εHf, interpreted as reworking of existing crust perhaps linked to terrane assembly. Felsic rocks from the Finnefjeld Orthogneiss Complex were derived from the same source at the same time as the surrounding tonalites, but from shallower melting, requiring any bolide-driven melting event to have occurred almost simultaneously alongside the production of the surrounding crust. A simpler alternative has the Finnefjeld Complex and surrounding tonalite representing the coeval genesis of evolved crust over a substantial lithospheric depth. Hafnium isotope data from the two major Mesoarchaean crust-forming episodes record a contribution from older mafic Eoarchaean crust. Invoking the involvement of an Eoarchaean root in the growth of younger Mesoarchaean crust puts important constraints on geodynamic models of the formation of the discrete terranes that ultimately assembled to form Earth's cratons.

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Section: Later Magmatic and Metamorphic Eventsmentioning

confidence: 60%

Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

Gardiner

Kirkland

Hollis

et al. 2019

Contrib Mineral Petrol

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“…(b) Tectonic subdivision of Altun–Qilian–Kunlun ( AQK ) orogenic system in the northeastern Tibet (compiled from Song et al., ; Yan et al., ; Zhang, Yu, et al., ). (c) Geological map of the North Wulan gneiss complex and localities of sampling (modified from Li et al., ) [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The North Wulan gneiss complex is exposed to the northeast of Wulan County (Figure c). It consists of orthogneiss, schist, calcsilicate rocks, metasandstone, marble, quartzite, amphibolite, pelitic and mafic granulites, and migmatite (Figures c and ), which are derived from Mesoproterozoic to early Palaeozoic protoliths (Li, Niu, Yan, Da, et al., ; Li, Niu, Yan, Wu, et al., ; Li et al., ; Wang et al., ). The Mesoproterozoic rocks are regarded as the crystalline basement of Oulongbuluke microcontinent (Chen et al., ; Lu et al., ).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Metamorphism and anatexis occurred at c . 480–450 Ma as determined from U–Pb zircon geochronology (Li, Niu, Yan, Da, et al., ; Li, Niu, Yan, Wu, et al., ; Li et al., ). The part of the P–T path that these ages record is unclear.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…(b) Tectonic subdivision of Altun-Qilian-Kunlun (AQK) orogenic system in the northeastern Tibet (compiled from Song et al, 2003;Yan et al, 2015;Zhang, Yu, et al, 2017). (c) Geological map of the North Wulan gneiss complex and localities of sampling (modified from Li et al, 2018) minerals in different samples are summarized in Table 1. Mineral abbreviations are from Whitney and Evans (2010) in addition to Liq for silicate melt.…”

Section: Petrographymentioning

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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The nature and history of the South Qilian orogenic belt: Constraints from compositions of rivers' sediments and their detrital zircon U–Pb geochronology, Lu‐Hf isotopic compositions

Kang

Chen

2019

Geological Journal

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Detrital zircon U-Pb dating, Hf isotopic data, and Nd isotopic compositions of river sediments are used to constrain crustal evolution processes of their provenance in the South Qilian orogenic belt. The detrital zircons from the Yuka, Tataleng, and Bayinguole rivers range in age from Neoarchean (2,772 Ma) to Permian (261 Ma), with age peaks at ca. 2.4 Ga, ca. 1.95 Ga, and ca. 0.45 Ga. Hf isotopic compositions of Paleoproterozoic, Pan-African, and Caledonian zircon age groups display a wide range of ε Hf (t) values, suggesting diverse sources of host magma of the zircon grains. The basement formation of the South Qilian orogenic belt from depleted mantle occurred at two stages; ca. 3.1-2.5 Ga and ca. 2.0-1.6 Ga. Meanwhile, the Nd model ages of silt-mud from the region are between 1.98 Ga and 2.27 Ga with an average value of 2.12 Ga. Our study indicates that the Qilian oceanic plate formed between the Qaidam and Alxa blocks from late Neoproterozoic to Silurian. The South Qilian orogenic belt is a product of the Qilian Ocean closure and subsequent collision between the Qaidam Block and central Qilian belt during Ordovician-Silurian times. Combining regional tectonothermal events with new results of river sediments suggests that rifting from a continent and opening of the Qilian Ocean occurred at ca. 780-520 Ma, subduction of the oceanic crust at ca. 520-440 Ma, ocean closure and continental subduction at ca. 440-420 Ma, exhumation of subducted crust at ca. 420-400 Ma, and orogenic collapse and extension at ca. 400-360 Ma. KEYWORDS detrital zircon, formation and evolution of crust, Nd isotope, Qilian oceanic plate, South Qilian orogenic belt, U-Pb-Hf isotopes

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Anatexis of former arc magmatic rocks during oceanic subduction: A case study from the North Wulan gneiss complex

Cited by 38 publications

References 98 publications

Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

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

The nature and history of the South Qilian orogenic belt: Constraints from compositions of rivers' sediments and their detrital zircon U–Pb geochronology, Lu‐Hf isotopic compositions

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