Geochronological and geochemical study of the Darbut Ophiolitic Complex in the West Junggar (NW China): Implications for petrogenesis and tectonic evolution

Yang, Gaoxue; Li, Yongjun; Gu, Pingyang; Yang, Baofeng; Tong, Lili; Zhang, Hongwei

doi:10.1016/j.gr.2011.07.029

Cited by 128 publications

(55 citation statements)

References 64 publications

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“…Recently, many types of diagnostic rock associations have been found in West Junggar strongly suggesting that ridge subduction was in operation during the late Carboniferous-early Permian Tang et al, 2010Tang et al, , 2012Yin et al, 2010Yin et al, , 2013aYin et al, , b, 2015bMa et al, 2012;Zhang et al, 2011a, b;Yang et al, 2012). In Japan, ridge subduction has occurred every 100 Ma in the last 450 Ma.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Late Silurian–early Devonian adakitic granodiorite, A-type and I-type granites in NW Junggar, NW China: Partial melting of mafic lower crust and implications for slab roll-back

et al. 2017

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Late Silurian-early Devonian adakitic granodiorite, A-type and I-type granites in NW Junggar, NW China: Partial melting of mafic lower crust and implications for slab roll-back, Gondwana Research (2015), AbstractLate Silurian-early Devonian magmatism of the NW Junggar region in the Central Asian Orogenic Belt provides a critical geological record that is important for unraveling regional tectonic history and constraining geodynamic processes. In this study, we report results of U-Pb zircon ages and systematic geochemical data for late Silurian-early Devonian largely granitic rocks in NW Junggar, aiming to constrain their emplacement ages, origin and geodynamic significance. The magmatism consists of a variety of mafic to felsic intrusions and volcanic rocks, e.g. adakitic granodiorite, K-feldspar granite, syenitic granite, gabbro and rhyrolite. U-Pb zircon ages suggest that the granitoids and gabbros were emplaced in the late Silurian-early Devonian (420-405 Ma). Adakitic granodiorites are calc-alkaline, characterized by high Sr (407-532 ppm), low Y (12.2-14.7 ppm), Yb (1.53-1.77 ppm), Cr (mostly < 8.00 ppm), Co (mostly <11.0 ppm) and Ni (mostly <4.10 ppm) and relatively high Sr/Y (31-42) ratios, analogous to those of modern adakites. K-feldspar granites and rhyolites are characterized by alkali-and Fe-enriched, with high Zr, Nb and Ga/Al ratios, geochemically similar to those of A-type granites. Syenitic granites show high alkaline (Na 2 O+K 2 O=8.39-9.34 wt.%) contents, low Fe # values (0.73-0.80) and are weakly peraluminous (A/CNK=1.00-1.07). Gabbros are characterized by low MgO (6.86-7.15 wt.%), Mg # (52-53), Cr (124-133 ppm) and Ni (84.7-86.6 ppm) contents. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 3 The geochemical characteristics of the gabbroic samples show affinity to both MORB-and arc-like sources. All granitoids have positive εNd(t) (+3.9 to +6.9) and zircon εHf(t) (+9.8 to +15.2) values and low initial 87 Sr/ 86 Sr ratios (0.7035-0.7043), with young T DM (Nd) (605-791 Ma) and T DM (Hf) (425-773 Ma) ages, suggesting significant addition of juvenile material. The adakitic granodiorites probably resulted from partial melting of mafic lower crust, leaving an amphibolite and garnet residue. The K-feldspar granites, rhyolites and syenitic granites probably formed from partial melting of the Xiemisitai mid-lower crust, while the gabbroic intrusion was probably generated by interactions between asthenospheric and metasomatized lithospheric mantle. Voluminous plutons of various types (adakites, A-type granites, I-type granites, and gabbros) formed during 420-405 Ma, and their isotopic data suggest significant additions of juvenile material. We propose that a slab roll-back model can account for the 420-405 Ma magmatic "flare up" in NW Junggar as well as an extensional setting.

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Section: Accepted Manuscriptmentioning

confidence: 99%

Late Silurian–early Devonian adakitic granodiorite, A-type and I-type granites in NW Junggar, NW China: Partial melting of mafic lower crust and implications for slab roll-back

et al. 2017

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“…1, inset B). In this terrane, several Paleozoic ophiolitic mélanges have been documented but no Precambrian basement rocks have been discovered (Yang et al, 2012;Zhang and Huang, 1992). The oldest Tangbale ophiolite yielded an imprecise age of 508 ± 60 Ma, while the youngest Karamay ophiolite has a SHRIMP zircon U-Pb age of 332 ± 14 Ma, reflecting a complex accretionary history from the Cambrian to the Carboniferous Kwon et al, 1989;Xu et al, 2006).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The tectonic setting of West Junggar has long been controversial, such as a post-collisional environment since the Early Carboniferous (Chen and Arakawa, 2005;Chen and Jahn, 2004;Fan et al, 2007;Han et al, 1997Han et al, , 2006Su et al, 2006;Xu et al, 2012), or a subduction setting in the Late Carboniferous (Geng et al, 2009;Ma et al, 2012;Tang et al, 2010Tang et al, , 2012aXiao et al, 2008Xiao et al, , 2009Yang et al, 2012;Yin et al, 2010;Zhang et al, 2011a,b). Based on the occurrence of the I-type and A-type granites and their undeformed and alkali-enriched characteristics, most granitic plutons in West Junggar were previously interpreted as post-collisional granites (Chen and Jahn, 2004;Xu et al, 2012).…”

Section: Tectonic Setting In the Late Carboniferousmentioning

confidence: 99%

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A Late Carboniferous–Early Permian slab window in the West Junggar of NW China: Geochronological and geochemical evidence from mafic to intermediate dikes

Yin¹,

Long²,

Yuan³

et al. 2013

Lithos

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“…The vast accretionary complexes of the CAOB contain a significant proportion of more-enriched basalts (Yang et al, 2015), similar in composition to modern-day ocean island basalts (OIB). On the basis of their geochemistry and nature of associated sediments many of these enriched basalts have been interpreted as the accreted remnants of seamounts (e.g., Safonova and Santosh, 2014;Yang et al, 2012aYang et al, , 2012bYang et al, , 2013Yang et al, , 2015. However, since accreted seamounts generally get caught up in ophiolitic mélange belts they have undergone intense deformation, so can easily be misinterpreted as "classic" ophiolitic units (cf.…”

Section: Introductionmentioning

confidence: 99%

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Yang

Kerr

et al. 2018

Journal of Asian Earth Sciences

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A B S T R A C T The Carboniferous Bayingou ophiolitic mélange is exposed in the North Tianshan accretionary complex in the southwestern part of the Central Asian Orogenic Belt (CAOB). The mélange is mainly composed of serpentinised ultramafic rocks (including harzburgite, lherzolite, pyroxenite, dunite and peridotite), pillowed and massive basalts, layered gabbros, radiolarian cherts, pelagic limestones, breccias and tuffs, and displays blockin-matrix structures. The blocks of ultramafic rocks, gabbros, basalts, cherts, and limestones are set in a matrix of serpentinised ultramafic rocks, massive basalts and tuffs. The basaltic rocks in the mélange show significant geochemical heterogeneity, and two compositional groups, one ocean island basalt-like, and the other mid-ocean ridge-like, can be distinguished on the basis of their isotopic compositions and immobile trace element contents (such as light rare earth element enrichment in the former, but depletion in the latter). The more-enriched basaltic rocks are interpreted as remnants/fragments of seamounts, derived from a deep mantle reservoir with low degrees (2-3%) of garnet lherzolite mantle melting. The depleted basalts most likely formed by melting of a shallower spinel lherzolite mantle source with ∼15% partial melting. It is probable that both groups owe their origin to melting of a mixture between plume and depleted MORB mantle. The results from this study, when integrated with previous work, indicate that the Junggar Ocean crust (comprising a significant number of seamounts) was likely to have been subducted southward beneath the Yili-Central Tianshan block in the Late Devonian-Early Carboniferous. The seamounts were scraped-off and accreted along with the oceanic crust in an accretionary wedge to form the Bayingou ophiolitic mélange. We present a model for the tectonomagmatic evolution of this portion of the CAOB involving prolonged intra-oceanic subduction with seamount accretion

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Geochronological and geochemical study of the Darbut Ophiolitic Complex in the West Junggar (NW China): Implications for petrogenesis and tectonic evolution

Cited by 128 publications

References 64 publications

Late Silurian–early Devonian adakitic granodiorite, A-type and I-type granites in NW Junggar, NW China: Partial melting of mafic lower crust and implications for slab roll-back

Late Silurian–early Devonian adakitic granodiorite, A-type and I-type granites in NW Junggar, NW China: Partial melting of mafic lower crust and implications for slab roll-back

A Late Carboniferous–Early Permian slab window in the West Junggar of NW China: Geochronological and geochemical evidence from mafic to intermediate dikes

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

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