Three‐dimensional electrical structure of the crust and upper mantle in Ordos Block and adjacent area: Evidence of regional lithospheric modification

Dong, Hui; Wei, Wenbo; Ye, Gaofeng; Jin, Sheng; Jones, Alan G.; Jing, Jianen; Zhang, Letian; Xie, Chengliang; Zhang, Fan; Wang, Hui

doi:10.1002/2014gc005270

Cited by 66 publications

(51 citation statements)

References 75 publications

(83 reference statements)

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“…Zhao et al [] interpreted the feature to be related to low temperatures and a relatively depleted geochemical composition. Consistent results from electromagnetic data demonstrate that a zone with low resistivity can be tracked downward to 150 km [see Dong et al , , Figure 5]. The zone of low resistivity moves southward as depth increases, which is in good agreement with that we see in the V p / V s ratio.…”

Section: Discussionmentioning

confidence: 99%

Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

Sun

2016

Geophysical Research Letters

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The Pn and Sn residuals from regional events provide strong constraints on the structure and lithological characteristics of the uppermost mantle beneath eastern China and its surroundings. With the dense Chinese Digital Seismic Network in eastern China, separate Pn and Sn tomographic inversions have been exploited to obtain P and S velocities at a resolution of 2° × 2° or better. The patterns of P velocities are quite consistent with the S velocities at depth of 50 and 60 km, but the amplitude of P wave speed anomalies are a little larger than those of S wave speed. The low P wave speed, high S wave speed, and low Vp/Vs ratio beneath the northern part of Ordos Basin are related to upwelling hot material. Abrupt changes in material properties are indicated from the rapid variations in the Vp/Vs ratio.

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Section: Discussionmentioning

confidence: 99%

Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

Sun

2016

Geophysical Research Letters

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“…conductivity domains were imaged beneath the North Anatolian fault (Kaya et al, 2013), the Red River fault system (Pham et al, 1995), and beneath suture zones in Asia and North America (Dong et al, 2014;Meqbel et al, 2014). In contrast, high resistivity is associated with the Great Slave shear zone up to 50 km depth (Yin et al, 2014) and with a Neoproterozoic collisional suture in northeast Brazil .…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Heterogeneity and anisotropy in the lithospheric mantle

Tommasi

Vauchez

2015

Tectonophysics

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International audienceThe lithospheric mantle is intrinsically heterogeneous and anisotropic. These two properties govern the repartition of deformation, controlling intraplate strain localization and development of new plate boundaries. Geophysical and geological observations provide clues on the types, ranges, and characteristic length scales of heterogeneity and anisotropy in the lithospheric mantle. Seismic tomography points to variations in geothermal gradient and hence in rheological behavior at scales of hundreds of km. Seismic anisotropy data substantiate anisotropic physical properties consistent at scales of tens to hundreds of km. Receiver functions imply lateral and vertical heterogeneity at scales < 10 km, which might record gradients in composition or anisotropy. Observations on naturally deformed peridotites establish that compositional heterogeneity and Crystal Preferred Orientations (CPOs) are ubiquitous from the mm to the km scales. These data allow discussing the processes that produce/destroy heterogeneity and anisotropy and constraining the time scales over which they are active. This analysis highlights: (i) the role of deformation and reactive percolation of melts and fluids in producing compositional and structural heterogeneity and the feedbacks between these processes, (ii) the weak mechanical effect of mineralogical variations, and (iii) the low volumes of fine-grained microstructures and difficulty to preserve them. In contrast, olivine CPO and the resulting anisotropy of mechanical and thermal properties are only modified by deformation. Based on this analysis, we propose that strain localization at the plate scale is, at first order, controlled by large-scale variations in thermal structure and in CPO-induced anisotropy. In cold parts of the lithospheric mantle , grain size reduction may contribute to strain localization, but the low volume of fine-grained domains limits this effect

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“…Previous regional seismic imaging revealed broad high velocities beneath the Ordos block extending to ≥ 200‐km depths (e.g., Jiang et al, ; Lei, ; Zhao et al, ), and receiver function studies indicated that the lithosphere‐asthenosphere boundary (LAB) is ~200 km deep (Chen et al, ), implying the presence of overall thick cratonic SCLM beneath the Ordos block. However, more recent geophysical observations suggest that lithospheric rejuvenation also occurs at the margins of Ordos during the late Cenozoic, resulting in significant intracratonic heterogeneities (Dong et al, ; Guo, Afonso, et al, ; Guo & Chen, , ; Yu & Chen, ). However, it is still unclear to what extent the SCLM of Ordos block is being modified and what is the dynamic mechanism responsible for the rejuvenation.…”

Section: Introductionmentioning

confidence: 99%

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Guo

Chen

et al. 2018

JGR Solid Earth

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We constructed a high‐resolution 3‐D Vs model of the northern Ordos block and its surrounding areas by surface wave tomography, which reveals significant intracratonic heterogeneities. In the western Ordos, the lithosphere thickness is ~200 km with shear velocities comparable to the high velocities of other Archean cratons worldwide. However, the lithosphere thins gradually toward the east and Vs drops by 2–3% in the uppermost mantle beneath the eastern Ordos, coincident with the high surface heat flow (~68 mW/m2 in average) there. This observation suggests that the thick, cratonic keel is only locally preserved beneath the western Ordos, and the eastern part of the Ordos seems to undergo local rejuvenation. At greater depths (>180 km), a low‐velocity channel is observed beneath the high‐velocity keel of the Ordos. Beneath the Datong volcanoes, a low‐velocity anomaly is observed, dipping westward with depth and closely following the slope of the lithosphere beneath the northern Ordos. This prominent low velocity is connected with the low‐velocity zone beneath the northern Ordos, which is further connected with the low‐velocity zone beneath the northeastern Tibetan Plateau (NET). We propose that the asthenosphere beneath the NET flows toward the northern Ordos in response to the continuous northward convergence of the Indian‐Eurasian continents, and the asthenosphere flows upward following the eastward thinning lithosphere which leads to decompression partial melting, which migrates upward to feed the Datong volcanoes. The significant variations of the lithospheric thickness of the Ordos block may control the distribution of the asthenospheric flow.

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Three‐dimensional electrical structure of the crust and upper mantle in Ordos Block and adjacent area: Evidence of regional lithospheric modification

Cited by 66 publications

References 75 publications

Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

Heterogeneity and anisotropy in the lithospheric mantle

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

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