Mantle structure and dynamics beneath SE Tibet revealed by new seismic images

Huang, Zhouchuan; Wang, Pan; Xu, Mingjie; Wang, Liangshu; Ding, Zhongli; Wu, Yanqiang; Xu, Min; Mi, Ning; Yu, Dan; Hua, Li

doi:10.1016/j.epsl.2014.11.040

Cited by 116 publications

(127 citation statements)

References 55 publications

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“…8). They are consistent with previous teleseismic P-wave tomographic studies (Yang et al, 2014;Huang et al, 2015;Li et al, 2006). A large-scale high-velocity perturbation (Hv2) appears in the 300 and 400 km depth sections in the central part (Fig.…”

Section: Resultssupporting

confidence: 80%

“…8). Huang et al (2015) also defined Figure 5. Checkerboard resolution test at 50, 100, 200, 300, 400, 500, 600, 700, and 800 km depth sections relative to the IASP91 1-D velocity model (Kennett and Engdahl, 1991).…”

Section: Resultsmentioning

confidence: 99%

“…In the past 2 decades, several seismic tomographic studies have been carried out on the Emeishan LIP and surrounding regions, including 2.5-D tomography of the uppermost mantle (Lü et al, 2014), ambient noise Love and Rayleigh wave tomography (Li et al, 2010(Li et al, , 2009, teleseismic P-wave tomography (Bai et al, 2011;Yang et al, 2014;Huang et al, 2015), local earthquake tomography Xu et al, 2012), interstation Pg and Sg differential travel-time tomography , and Pn anisotropic tomography (Lei et al, 2014). These works have revealed the velocity structure of the crust and upper mantle beneath this region, although they did not directly address the mechanism of the Emeishan LIP formation.…”

Section: Introductionmentioning

confidence: 99%

“…These works have revealed the velocity structure of the crust and upper mantle beneath this region, although they did not directly address the mechanism of the Emeishan LIP formation. Huang et al (2015) carried out a tomographic study using 411 temporary stations within 20-33 • N and 95-110 • E and obtained the velocity structure of the crust and upper mantle in the Chuandian area. Here, we carry out an extended study in the region northward and eastward within 20-35 • N and 97-111 • E so as to cover all the regions of the Emeishan LIP.…”

Section: Introductionmentioning

confidence: 99%

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Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

Santosh

2017

Solid Earth

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Abstract. The voluminous magmatism associated with large igneous provinces (LIPs) is commonly correlated to upwelling plumes from the core-mantle boundary (CMB). Here we analyse seismic tomographic data from the Emeishan LIP in southwestern China. Our results reveal vestiges of delaminated crustal and/or lithospheric mantle, with an upwelling in the upper mantle beneath the Emeishan LIP rather than a plume rooted in the CMB. We suggest that the magmatism and the Emeishan LIP formation might be connected with the melting of delaminated lower crustal and/or lithospheric components which resulted in plume-like upwelling from the upper mantle or from the mantle transition zone.

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Section: Resultssupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

Santosh

2017

Solid Earth

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“…1 Earthq Sci (2016) 1989) model. Seismic tomography shows important extensive low-velocity zones in the upper mantle under Yunnan which are proposed as back-arc spreading due to the subduction of the Indian or Burman Plate (e.g., Ni et al 1989;Li et al 2008;Lei et al 2009;Wang et al 2010;Wei et al 2012;Huang et al 2015b). There is possible asthenospheric flow from SE Tibet to eastern China (e.g., Li et al 2008;Lei et al 2014;Huang et al 2015b, c) that may probably help the lithosphere of the Indochina and South China blocks above it move southeastward (e.g., Tapponnier et al 1982Tapponnier et al , 2001.…”

Section: Discussionmentioning

confidence: 99%

Crustal stress field in Yunnan: implication for crust-mantle coupling

Huang

Wang

et al. 2016

Earthq Sci

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We applied the gCAP algorithm to determine 239 focal mechanism solutions 3:0 M W 6:0 ð Þwith records of dense ChinArray stations deployed in Yunnan, and then inverted 686 focal mechanisms (including 447 previous results) for the regional crustal stress field with a damped linear inversion. The results indicate dominantly strike-slip environment in Yunnan as both the maximum (r 1 ) and minimum (r 3 ) principal stress axes are sub-horizontal. We further calculated the horizontal stress orientations (i.e., maximum and minimum horizontal compressive stress axes: S H and S h , respectively) accordingly and found an abrupt change near *26°N. To the north, S H aligns NW-SE to nearly E-W while S h aligns nearly N-S. In contrast, to the south, both S H and S h rotate laterally and show dominantly fan-shaped patterns. The minimum horizontal stress (i.e., maximum strain axis) S h rotates from NW-SE to the west of Tengchong volcano gradually to nearly E-W in west Yunnan, and further to NE-SW in the South China block in the east. The crustal strain field is consistent with the upper mantle strain field indicated by shear-wave splitting observations in Yunnan but not in other regions. Therefore, the crust and upper mantle in Yunnan are coupled and suffering vertically coherent pure-shear deformation in the lithosphere.

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P wave tomography and anisotropy beneath Southeast Asia: Insight into mantle dynamics

2015

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Southeast Asia is surrounded by subduction zones resulting from the interactions of several lithospheric plates. Its evolution has been also influenced by active tectonics due to the Indo‐Asian collision in the Cenozoic. In this study, we use a large number of arrival‐time data of local and regional earthquakes to determine 3‐D P wave tomography and azimuthal anisotropy in the mantle beneath SE Asia. High‐velocity (high‐V) anomalies representing the subducting slabs are clearly visible in the upper mantle and the mantle transition zone (MTZ). Low‐velocity (low‐V) zones with trench‐normal anisotropy are revealed in the uppermost mantle, which indicate back‐arc spreading or secondary mantle‐wedge flow induced by the slab subduction. In contrast, trench‐parallel anisotropy dominates in the deep upper mantle and reflects structures either in the subducting slab or in the upper mantle surrounding the slab. The trench‐parallel anisotropy is also significant in the lower MTZ, which may contribute to shear wave splitting observations. A low‐V body extending down to the lower mantle is visible under the Hainan volcano far away from the plate boundaries, suggesting that Hainan is a hot spot fed by a lower‐mantle plume. The low‐V body under Hainan is connected with low‐V zones in the upper mantle under SE Tibet and Vietnam. Our P wave anisotropy results reflect significant mantle flow existing in the asthenosphere from SE Tibet to Hainan and further southwestward to Vietnam. The present study, especially the 3‐D P wave anisotropy results, provides important new insight into mantle dynamics in SE Asia.

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Mantle structure and dynamics beneath SE Tibet revealed by new seismic images

Cited by 116 publications

References 55 publications

Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

Mantle roots of the Emeishan plume: an evaluation based on teleseismic P-wave tomography

Crustal stress field in Yunnan: implication for crust-mantle coupling

P wave tomography and anisotropy beneath Southeast Asia: Insight into mantle dynamics

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