Crustal structure of the eastern Qinling orogenic belt and implication for reactivation since the Cretaceous

Guo, Zhen; Chen, Y. John

doi:10.1016/j.tecto.2016.06.007

Cited by 27 publications

(10 citation statements)

References 67 publications

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“…Shear wave splitting measurements also suggested that the asthenosphere mantle flow existed beneath the WQT [e.g., Chang et al ., ; Yu and Chen , ]. The absence of mafic lower crust characterized by high velocity is obvious from our 3‐D V s model (Figure c) and DSS studies [ Vergne et al ., ; Liu et al ., ], which could be a consequence of removal of mafic lower crust [ Chung et al ., ; Guo and Chen , ]. Petrological study suggested a granodioritic to quartz‐dioritic crustal composition beneath the WQT [e.g., Gao et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

Xingchen

Ding

et al. 2017

JGR Solid Earth

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We present a new 3‐D lithospheric Vs model for the NE Tibetan Plateau (NETP) and the western North China Craton (NCC). First, high‐frequency receiver functions (RFs) were inverted using the neighborhood algorithm to estimate the sedimentary structure beneath each station. Then a 3D Vs model with unprecedented resolution was constructed by jointly inverting RFs and Rayleigh wave dispersions. A low‐velocity sedimentary layer with thicknesses varying from 2 to 10 km is present in the Yinchuan‐Hetao graben, Ordos block, and western Alxa block. Velocities from the middle‐lower crust to the uppermost mantle are generally high in the Ordos block and low in the Alxa block, indicating that the Alxa block is not part of the NCC. The thickened crust in southwestern Ordos block and western Alxa block suggests that they have been modified. Two crustal low‐velocity zones (LVZs) were detected beneath the Kunlun Fault (KF) zone and western Qilian Terrane (QLT). The origin of the LVZ beneath the KF zone may be the combined effect of shear heating, localized asthenosphere upwelling, and crustal radioactivity. The LVZ in the western QLT, representing an early stage of the LVZ that has developed in the KF zone, acts as a decollement to decouple the deformation between the upper and lower crust and plays a key role in seismogenesis. We propose that the crustal deformation beneath the NETP is accommodated by a combination of shear motion, thickening of the upper‐middle crust, and removal of lower crust.

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Section: Discussionmentioning

confidence: 99%

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

Xingchen

Ding

et al. 2017

JGR Solid Earth

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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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“…In our research area, there are two notable geological features, namely, the basin‐range system in the north that includes the Qinling Mountains and the Weihe Basin and the Dabashan Orocline system in the south that includes the Dabashan Mountains, the Shennongjia‐Huangling (SNHL) dome, the Hannan‐Micang (HNMC) dome, and the Sichuan Basin (Figure b). Although the uplift and exhumation of the Qinling Mountains (Chen et al, ; Enkelmann et al, ; Guo & Chen, ; Hu et al, ) and the extension of the Weihe Basin (Bao et al, ; Bao, Song, et al, ; Rao et al, ; Tang et al, ; Y. Zhang et al, ) have been studied thoroughly and separately, the relationship between the Qinling Mountains and Weihe Basin has not been fully discussed. In recent years, the Dabashan Orocline has received extensive attention (Dong et al, ; J. Li et al, ; Shi et al, , ).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, high‐resolution surface wave tomography using cross‐correlation functions estimated from ambient noise within a dense seismic array has become an effective method for investigating fine‐scale structures in the continental crust and uppermost mantle (Guo & Chen, ; H. Li, Li, et al, 2012). In this study, we employ seismic data from a temporary linear array (Si et al, ) and the China National Seismic Network (Zheng et al, ) to measure the group and phase velocity dispersion curves at periods from 8 to 44 s, after which we jointly invert the data to obtain a high‐resolution three‐dimensional (3‐D) velocity model for the QOB and its adjacent areas.…”

Section: Introductionmentioning

confidence: 99%

“…The blue line demarcates the North-South Gravity Lineament dome, and the Sichuan Basin (Figure 1b). Although the uplift and exhumation of the Qinling Mountains Enkelmann et al, 2006;Guo & Chen, 2016;Hu et al, 2006) and the extension of the Weihe Basin (Bao et al, 2013;Rao et al, 2014;Tang et al, 2015;Y. Zhang et al, 1998) have been studied thoroughly and separately, the relationship between the Qinling Mountains and Weihe Basin has not been fully discussed.…”

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confidence: 99%

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Flyover Crustal Structures Beneath the Qinling Orogenic Belt and Its Tectonic Implications

et al. 2018

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Determining high‐resolution three‐dimensional (3‐D) crustal structures of the Qinling Orogenic Belt (QOB) can reveal significant evidences to enhance our understanding of its tectonic evolution. By jointly inverting group and phase velocity dispersion curves, we obtain a high‐resolution 3‐D shear wave velocity model for the QOB. According to the obviously layered features, which include an E‐W trending high‐velocity structure in the upper crust (0–10 km), a transitional zone in the middle crust (10–30 km), and an approximately N‐S trending low‐velocity zone in the middle‐lower crust (20–40 km), we elucidate the crustal structure as a flyover model to explain how the crust beneath the QOB was deformed under the perpendicular force systems from the NE‐SW and E‐W directions during the Meso‐Cenozoic. First, the apparent NE‐SW trending low‐velocity zone in the middle‐lower crust indicates that the low‐viscosity crustal materials beneath the northeastern Tibetan Plateau did not flow eastward into the eastern Qinling terrane during the Cenozoic. Second, the extension in the northern Qinling Mountains and Weihe Basin was not largely affected by the lateral crustal growth of the NE Tibetan Plateau, which might be the result of deep mantle upwelling and/or residual effects from the subduction of the western Pacific plate. Third, during the Mesozoic, the high‐velocity structures beneath the Hannan‐Micang and Shennongjia‐Huangling domes served as anchors resisting the northward subduction, rotation, and continuous collision of the Yangtze Block. The eastward extruding Hannan‐Micang dome served as an indenter that eventually shaped the present‐day asymmetric style of the Dabashan Orocline during the Cenozoic.

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Crustal structure of the eastern Qinling orogenic belt and implication for reactivation since the Cretaceous

Cited by 27 publications

References 67 publications

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

Three‐dimensional lithospheric S wave velocity model of the NE Tibetan Plateau and western North China Craton

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

Flyover Crustal Structures Beneath the Qinling Orogenic Belt and Its Tectonic Implications

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