3-D density structure under South China constrained by seismic velocity and gravity data

Deng, Yangfan; Zhang, Zhongjie; Badal, José; Wu, Fan

doi:10.1016/j.tecto.2013.07.032

Cited by 70 publications

(37 citation statements)

References 69 publications

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“…The inverted density structures of P1-P4 are shown in Figure 4; the structures have a conspicuous layered feature, which provides information about the crust, upper mantle density, and the rheology of each profile. According to Deng et al (2014) and Zhang et al (2017), the fit between the observed and calculated gravity anomalies strongly supports the reliability of the results, and we therefore validated our results using this method. Inside the Ordos Block and Qinling Orogen, the mismatch was found to be less than 2 mGal.…”

Section: Density Structures Of Crust Beneath the Qinling Orogensupporting

confidence: 82%

Crustal Density Structure, Lithosphere Flexure Mechanism, and Isostatic State Throughout the Qinling Orogen Revealed by In Situ Dense Gravity Observations

Wang

She

2018

JGR Solid Earth

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Gravity and GPS hybrid measurements were conducted at 385 stations throughout the Qinling Orogen, China, to update Bouguer gravity anomalies and free‐air gravity anomalies of the area. The crustal density structure, lithosphere flexure mechanism, and isostatic state of the Qinglin Orogen were studied in detail via these in situ observations. Bouguer gravity anomalies in the study area are mainly negative, ranging from −410 mGal in the Tibetan Plateau to −100 mGal in the eastern Qinglin Orogen. The estimated crustal thickness ranges from 56 to 35 km and thins eastward along the Qinling Orogen. The optimal effective elastic thickness (Te) of the study area is 14 km, and the loading comes from the Earth's surface, the interface between the upper and lower crust, and the Moho. Vertical tectonic stress borne by the lithosphere varies observably in the study area. Downward stress reaches a peak of −14 MPa in the Liupanshan Mountains, whereas the highest value of upward stress (8 MPa) is attained in the middle Qinling Orogen. Considering distributions of crustal density structures and vertical tectonic stress of the lithosphere, in addition to the distinct loading ratios of the eastern and western Qinling Orogen, a piecewise combination model was developed to interpret the uplift of the Qinling Orogen. This model shows that the eastern part of the Orogen is thickened by the upward migration of mantle materials under the thrusting of the South and North China Blocks, whereas uplift of the western part results from lower crustal flow derived from the Tibetan Plateau.

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Section: Density Structures Of Crust Beneath the Qinling Orogensupporting

confidence: 82%

Crustal Density Structure, Lithosphere Flexure Mechanism, and Isostatic State Throughout the Qinling Orogen Revealed by In Situ Dense Gravity Observations

Wang

She

2018

JGR Solid Earth

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“…The correlation coefficient is as high as 0.93 for the SE part and decreases to 0.75 for the NE part (the core of the Yangtze craton). The crustal thickness corresponding to zero altitude is large in the NE part, which may be related to a mantle lithosphere with high rock density and high seismic velocity [ Deng et al , ], showing the features of a stable block.…”

Section: Discussionmentioning

confidence: 99%

“…The density perturbation of the deep equivalent layer at 35.3 km shows that there are relatively high density anomalies in the middle and lower crust beneath northern Yangtze craton [ Yang et al , ] and a very high density anomaly at the top of the upper mantle beneath the Sichuan basin [ Deng et al , ]. The high‐density and high‐velocity lithosphere beneath the Sichuan basin [ Deng et al , ] corresponds to large crustal thickness at zero altitude, which may indicate that the high‐density lithosphere has a downward drag effect on the crust as a whole. It suggests that the crustal thickness in the northern part is not perfectly in accordance with the isostasy model and it achieves regional isostasy at lithospheric depth.…”

Section: Discussionmentioning

confidence: 99%

Crustal thickness and Poisson's ratio in southwest China based on data from dense seismic arrays

Wang

Fang

et al. 2017

JGR Solid Earth

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Crustal thickness and Poisson's ratio are important parameters to characterize regional isostasy state and material composition or state. Using the teleseismic waveform data from 141 permanent stations and 785 temporary stations in southwest China, we obtain the crustal thickness and average Poisson's ratio by the H‐κ stacking of receiver functions. In the west (the SE Tibetan Plateau and the Yunnan‐Burma‐Thailand block) and southeast (the Cathaysian block and southern Yangtze craton) of the study region, there are high correlation coefficients for the crustal thicknesses between what we obtain from the receiver functions and what we calculate from the Airy isostasy model, indicating that a state of isostasy can be achieved at the crust‐mantle boundary beneath these two regions. In the northeast (northern Yangtze craton), the correlation coefficient is lower, indicating that the effect of the lithosphere needs to be considered for a regional isostasy. Intermediate Poisson's ratios (0.26 ≤ σ ≤ 0.28) are found beneath the northern Panzhihua‐Emeishan region. Combing the high‐velocity features from previous study, we speculate that it may be related to the Emeishan large igneous province. High Poisson's ratios (σ > 0.28) are found beneath the SE Tibetan Plateau and the nearby strike‐slip faults, such as the Anninghe‐Zemuhe fault and the northern Xiaojiang fault. Combing the low‐velocity zones from previous study, we speculate that there may be partially melted and lower crustal flow.

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“…There are several methods to calculate the gravity anomaly, such as the cuboid method (Deng et al, 2014a(Deng et al, , 2014b and the polygon method (Jia and Meng, 2009;Wang et al, 2014aWang et al, , 2014b. In this study, we use the latter one, assuming that the gravity anomaly is generated by a horizontal polygonal prism lying parallel to the y axis, such that the subsurface mass can be divided into a finite number of these prisms (Jia and Meng, 2009).…”

Section: Gravitational Effect Of the Sedimentsmentioning

confidence: 99%

Magmatic underplating beneath the Emeishan large igneous province (South China) revealed by the COMGRA-ELIP experiment

et al. 2016

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3-D density structure under South China constrained by seismic velocity and gravity data

Cited by 70 publications

References 69 publications

Crustal Density Structure, Lithosphere Flexure Mechanism, and Isostatic State Throughout the Qinling Orogen Revealed by In Situ Dense Gravity Observations

Crustal Density Structure, Lithosphere Flexure Mechanism, and Isostatic State Throughout the Qinling Orogen Revealed by In Situ Dense Gravity Observations

Crustal thickness and Poisson's ratio in southwest China based on data from dense seismic arrays

Magmatic underplating beneath the Emeishan large igneous province (South China) revealed by the COMGRA-ELIP experiment

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