Eocene supra-subduction zone mafic magmatism in the Sibumasu Block of SW Yunnan: Implications for Neotethyan subduction and India–Asia collision

Wang, Yuejun; Zhang, Limin; Cawood, Peter A.; Ma, Licheng; Wu, Fan; Zhang, Aimei; Zhang, Yuzhi; Bi, Xian‐Wu

doi:10.1016/j.lithos.2014.08.012

Cited by 43 publications

(23 citation statements)

References 97 publications

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“…In addition, no matter whether the model contains crust eclogitization or not, oceanic slab breakoff can significantly promote exhumation of the subducted continental crustal materials and asthenospheric upwelling, inducing a considerable heating in the collision zone. Our numerical results reasonably explain the flare-ups of the Gangdese igneous rocks in South Lhasa and rapid exhumation of the subducted continental crust at ~50 Ma in response to the slab breakoff (Wang Y et al, 2015(Wang Y et al, , 2014Chung et al, 2005). Meanwhile, the altitude of the collision zone can sharply increase by ~1 000 m in response to the slab breakoff (Fig.…”

Section: Thermal and Topography Evolution On The India-asia Early Colsupporting

confidence: 69%

Effects of crustal eclogitization on plate subduction/collision dynamics: Implications for India-Asia collision

Huangfu

Wang

et al. 2016

J. Earth Sci.

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2D thermo-mechanical models are constructed to investigate the effects of oceanic and continental crustal eclogitization on plate dynamics at three successive stages of oceanic subduction, slab breakoff, and continental subduction. Crustal eclogitization directly increases the average slab density and accordingly the slab pull force, which makes the slab subduct deeply and steeply. Numerical results demonstrate that the duration time from initial continental collision to slab breakoff largely depends on the slab pull force. Specifically, eclogitization of subducted crust can greatly decrease the duration time, but increase the breakoff depth. The detachment of oceanic slab from the pro-continental lithosphere is accompanied with obvious exhumation of the subducted continental crust and a sharp uplift of the collision zone in response to the disappearance of downward drag force and the induced asthenospheric upwelling, especially under the condition of no or incomplete crustal eclogitization. During continental subduction, the slab dip angle is strongly correlated with eclogitization of subducted continental lower crust, which regulates the slab buoyancy nature. Our model results can provide several important implications for the Himalayan-Tibetan collision zone. For example, it is possible that the lateral variations in the degree of eclogitization of the subducted Indian crust might to some extent contribute to the lateral variations of subduction angle along the Himalayan orogenic belt. Moreover, the accumulation of highly radiogenic sediments and upper continental crustal materials at the active margin in combination with the strong shear heating due to continuous continental subduction together cause rising of isotherms in the accretionary wedge, which facilitate the development of crustal partial melting and metamorphism.

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Section: Thermal and Topography Evolution On The India-asia Early Colsupporting

confidence: 69%

Effects of crustal eclogitization on plate subduction/collision dynamics: Implications for India-Asia collision

Huangfu

Wang

et al. 2016

J. Earth Sci.

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“…In this scenario, the fluids and/or melts released from the subducted slab would have metasomatized the continental lithospheric mantle, as shown for the mafic dikes in the eastern part of the southern Lhasa Subterrane (Gao et al, ; Ma et al, ; Yue & Ding, ; Zhao et al, ). The latter is also the case in the Yunnan Province east of Tibet (Xu et al, ; Wang et al, ), where the dikes show island‐arc‐like geochemical characteristics. On incompatible trace element diagrams, the Daju mafic rocks show enriched trace element characteristics.…”

Section: Discussionmentioning

confidence: 79%

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Huang

Zeng

et al. 2017

Geochem Geophys Geosyst

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Oceanic slab breakoff significantly affects the thermal regime of the lithosphere during continental collision. This often triggers extension‐related mafic magmatism and crustal melting. It is generally accepted that the Neo‐Tethyan lithosphere subducted beneath the southern Lhasa Subterrane, resulting in the formation of the Gangdese magmatic arc. However, the timing of slab breakoff is still disputed, due to a lack of evidence for extension‐related mafic magmatism. In this study, we provide comprehensive age, element and Sr–Nd–Hf isotopic data of mafic dikes, felsic intrusions, and enclaves from the Daju area, southern Lhasa Subterrane. The timing of mafic dikes and granitoids are contemporaneous at circa 57 Ma. The mafic dikes are characterized by high Th/U, and Zr/Y ratios, their geochemistry indicates an intraplate affinity rather than arc magmas. Furthermore, the mafic dikes show strongly variable igneous zircon ɛHf(t), and lower whole‐rock ɛNd(t) than granitoids. This evidence suggests that the mafic dikes represent asthenosphere‐derived melts contaminated by various degrees of ancient lithosphere. However, the granitoids were directly derived from the juvenile lower crust. Given the abrupt decrease in the convergence rate between India and Asia, and the surface uplift and sedimentation cessation in the southern Lhasa Subterrane in the early Cenozoic, the occurrence of synchronous mafic dikes and granitoids is best explained by a slab breakoff model. The occurrence of intraplate‐type magmas likely corresponds to the magmatic expression of the initial stage of Neo‐Tethyan slab breakoff. The slab breakoff concept also explains the onset of the magmatic “flare‐up” and crustal growth after 57 Ma.

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“…The Lhasa terrane is a ~200-300-km-wide continental strip that trends east-west in southern Tibet and wraps around the eastern Himalayan Haproff et al | Northern Indo-Burma Ranges framework and lateral correlation of Himalayan-Tibetan lithologic units GEOSPHERE | Volume 15 | Number 3 syntaxis to a north-south trend in northern Myanmar and western Yunnan of China (e.g., Lin et al, 2013;Wang et al, 2014) (Fig. 1B).…”

Section: Lhasa Terranementioning

confidence: 99%

Geologic framework of the northern Indo-Burma Ranges and lateral correlation of Himalayan-Tibetan lithologic units across the eastern Himalayan syntaxis

et al. 2019

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The Cenozoic India-Asia collision generated both the east-trending Himalayan orogen and the north-trending Eastern and Western Flanking Belts located along the margins of the Indian subcontinent. Although the tectonic development of both flanking belts is key to understanding mechanisms of continental deformation during indenter-induced collision, few field-based studies coupled with geochronological and geochemical methods have been applied to these tectonic domains. In this study, we investigate the lateral correlation of lithologic units between the northern Indo-Burma Ranges, the northernmost segment of the Eastern Flanking Belt, and the eastern Himalayan-Tibetan orogen by integrating field observations, U-Pb zircon geochronology, and whole-rock geochemistry. Our findings provide new quantitative constraints to interpretations that the northern Indo-Burma Ranges expose the eastward continuation of several lithologic units of the Himalayan orogen and Lhasa terrane. Our field work documents a stack of thrust-bounded lithologic units present in the study area. The northernmost and structurally highest Lohit Plutonic Complex consists of Mesoproterozoic basement rocks (ca. 1286 Ma) and Late Jurassic-Cretaceous granitoids (ca. 156-69 Ma) with positive ε Nd values and initial 87 Sr/ 86 Sr ratios of ~0.705, which are correlative to the Bomi-Chayu complex and the northern Gangdese batholith, respectively. The structurally lower Tidding-Mayodia mélange complex, composed of basalt, gabbro, ultramafic rocks, and mafic schist of a dismembered ophiolite sequence, is interpreted in this study as the eastward extension of the Indus-Yarlung suture zone. Structurally below the suture zone are the Mayodia gneiss and Lalpani schist, which are interpreted to correlate with the Lesser Himalayan Sequence based on comparable metamorphic lithologies, negative ε Nd values, and similar Mesoproterozoic-Cambrian detrital zircon age spectra. In contrast to the above metamorphic units, the structurally lowest Tezu unit consists of siliciclastic strata that may be correlated with the Miocene-Pliocene Siwalik Group of the Himalayan orogen. Despite the above correlations, notable Himalayan-Tibetan lithologic units are absent in the northern Indo-Burma Ranges, including the Mesozoic-Cenozoic southern Gangdese batholith belt and its cover sequence of the Linzizong volcanic rocks, Xigaze forearc basin, Tethyan Himalayan Sequence, and Greater Himalayan Crystalline Complex of south-central Tibet and the central Himalaya. We interpret the absence of these lithologic units to be a result of a greater magnitude of crustal shortening and/or underthrusting of the Indian cratonal rocks than that across the Himalayan orogen to the west. This interpretation is supported by a southward decrease in the map-view distance between the active range-bounding thrust and the Indus-Yarlung suture zone in the northern Indo-Burma Ranges, from ~200 km in the north near the eastern Himalayan syntaxis to ~5 km in the south across a distance of ~200-300 km.

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Eocene supra-subduction zone mafic magmatism in the Sibumasu Block of SW Yunnan: Implications for Neotethyan subduction and India–Asia collision

Cited by 43 publications

References 97 publications

Effects of crustal eclogitization on plate subduction/collision dynamics: Implications for India-Asia collision

Effects of crustal eclogitization on plate subduction/collision dynamics: Implications for India-Asia collision

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Geologic framework of the northern Indo-Burma Ranges and lateral correlation of Himalayan-Tibetan lithologic units across the eastern Himalayan syntaxis

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