3-D electrical structure across the Yadong-Gulu rift revealed by magnetotelluric data: New insights on the extension of the upper crust and the geometry of the underthrusting Indian lithospheric slab in southern Tibet

Wang, Gang; Wei, Wenbo; Ye, Gaofeng; Jin, Sheng; Jing, Jianen; Zhang, Letian; Dong, Hui; Xie, Chengliang; Omisore, Busayo Oreoluwa; Guo, Zhenhua

doi:10.1016/j.epsl.2017.06.027

Cited by 53 publications

(44 citation statements)

References 48 publications

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“…According to a deep conductor beneath the Yadong‐Gulu rift from an MT model, G. Wang et al. (2017) suggested that rifts were caused by tearing of the Indian lithospheric slab. However, a new mechanism of “extensional extrusion” was suggested in the study of Dong et al.…”

Section: Discussionmentioning

confidence: 99%

“…Some geophysical studies have suggested that asthenospheric upwelling enters the upper layer through gaps and/or tearing windows (X. Tian, Chen, et al, 2015;G. Wang et al, 2017).…”

Section: Melting Mechanismsmentioning

confidence: 99%

“…Tian, Chen, et al (2015) argued a weakly coupled mechanism between surface and deep structures, although asthenospheric upwelling contributed to the pattern of extension across the rifts. According to a deep conductor beneath the Yadong-Gulu rift from an MT model, G. Wang et al (2017) suggested that rifts were caused by tearing of the Indian lithospheric slab. However, a new mechanism of "extensional extrusion" was suggested in the study of Dong et al (2016), in which higher density MT array data were used.…”

Section: Crustal East-west Extensionsmentioning

confidence: 99%

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Middle Crustal Partial Melting Triggered Since the Mid‐Miocene in Southern Tibet: Insights From Magnetotelluric Data

et al. 2021

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A weak middle crust induced by fluid phases is generally considered to exist beneath the Himalayan‐Tibetan orogen; however, there remains controversy regarding the interpretation of high‐conductivity and low‐velocity regions imaged in various geophysical studies. To better understand middle crustal rheological behaviors and associated triggering mechanisms beneath southern Tibet, we present a geoelectrical model derived from a three‐dimensional magnetotelluric inversion in this study. An effective conductivity of 0.3 S/m at depths of 10–28 km indicates a high melt fraction of ∼35 vol% in the Lhasa terrane. In the Tethyan Himalayan orogen, an effective conductivity of <0.2 S/m corresponds to a melt fraction <15 vol%, which is lower than previous estimations. We obtain very low viscosities either from laboratory data (1010–1012 Pa s) or empirical models (1016–1018 Pa s). A combination of radiogenic heat and strain heating may account for the weakened middle crust. We prefer a weak coupling between crustal east‐west extensions and mantle lithospheric deformations.

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Section: Discussionmentioning

confidence: 99%

“…Some geophysical studies have suggested that asthenospheric upwelling enters the upper layer through gaps and/or tearing windows (X. Tian, Chen, et al, 2015;G. Wang et al, 2017).…”

Section: Melting Mechanismsmentioning

confidence: 99%

Section: Crustal East-west Extensionsmentioning

confidence: 99%

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Middle Crustal Partial Melting Triggered Since the Mid‐Miocene in Southern Tibet: Insights From Magnetotelluric Data

et al. 2021

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“…Previous studies (e.g., Comeau et al., 2018; Le Pape et al., 2015; ten Grotenhuis et al., 2005; Unsworth et al., 2005; Wang et al., 2017a) have shown that Archie's law is a feasible method to estimate the melt fraction of conductors when partial melt is interconnected. Furthermore, the melt fraction can be used as a proxy for viscosity (e.g., Comeau et al., 2016), and can then be used to determine whether the strength of the mid to lower crust meet the condition to deform locally, and thus whether it may be linked to the deformation of the upper crust or mechanically disassociated.…”

Section: Constraints On Rheology From the Electrical Conductivity Str...mentioning

confidence: 99%

Lithospheric Structure Near the Northern Xainza‐Dinggye Rift, Tibetan Plateau–Implications for Rheology and Tectonic Dynamics

et al. 2021

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“…Multiple tectonic events, and their superposition, have influenced the tectonic development of the Songliao Block, including the Paleo‐Asian Ocean closure, the Mongol‐Okhotsk Ocean closure, and the Paleo‐Pacific subduction system (e.g., Y. Liu et al., 2017; T. Wang et al., 2017; Wu et al., 2011; Xu, Pei, et al., 2013). Geophysical data (e.g., Fu et al., 2019; Yang et al., 2003) indicate that despite the superposition of later tectonic domains, the signatures of remnants of the pre‐existing tectonic systems can still be observed, and they suggest a complex tectonic history.…”

Section: Discussionmentioning

confidence: 99%

Evidence for the Superposition of Tectonic Systems in the Northern Songliao Block, NE China, Revealed by a 3‐D Electrical Resistivity Model

Wang

Comeau

et al. 2022

JGR Solid Earth

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The creation and evolution of the Songliao Block, Northeast China, is believed to be related to the closure of the Paleo‐Asian and Mongol‐Okhotsk oceans, and to the subduction of the Paleo‐Pacific Ocean. Geochemical and geophysical data indicate a complex tectonic history that may have left signatures of the superposition of separate tectonic events. However, the relationship between the current lithospheric structure of the Songliao Block and those tectonic events is not clear. In order to shed light on this question, a three‐dimensional electrical resistivity model of the crust and mantle was generated from 138 magnetotelluric sites. The results show a heterogenous lithosphere with anomalous low‐resistivity zones (∼10 Ω·m). The position of upper‐crustal features (<10 km) correlates with a network of fault systems and rift basins. Based on estimates of high crustal temperatures, mid‐lower crustal features (15–35 km), some of which appear near seismic reflectors, are attributed to partial melts (∼5%) containing moderate‐high water contents (4.5 wt. %). A deep (>45 km) feature is interpreted as an asthenospheric upwelling near the center of the Songliao Block, where seismic evidence indicates a thin lithosphere. It is proposed that the collision, convergence, and suturing of blocks caused by the closure of the Paleo‐Asian Ocean and the bidirectional convergence between the Mongol‐Okhotsk and Paleo‐Pacific Ocean may have produced weak tectonic zones throughout the lithosphere. They provided a structural basis for the later upward movement of fluids and melt, likely due to hydrous upwellings caused by the subduction of the Paleo‐Pacific system.

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3-D electrical structure across the Yadong-Gulu rift revealed by magnetotelluric data: New insights on the extension of the upper crust and the geometry of the underthrusting Indian lithospheric slab in southern Tibet

Cited by 53 publications

References 48 publications

Middle Crustal Partial Melting Triggered Since the Mid‐Miocene in Southern Tibet: Insights From Magnetotelluric Data

Middle Crustal Partial Melting Triggered Since the Mid‐Miocene in Southern Tibet: Insights From Magnetotelluric Data

Lithospheric Structure Near the Northern Xainza‐Dinggye Rift, Tibetan Plateau–Implications for Rheology and Tectonic Dynamics

Evidence for the Superposition of Tectonic Systems in the Northern Songliao Block, NE China, Revealed by a 3‐D Electrical Resistivity Model

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