Weakness of the lower continental crust: a condition for delamination, uplift, and escape

Meißner, R.; Mooney, Walter D.

doi:10.1016/s0040-1951(98)00136-x

Cited by 214 publications

(133 citation statements)

References 54 publications

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“…Part of the SCIL might subduct and delaminate, possibly partly laterally because of the beginning of strong anisotropy slightly south oft he BNS (Huang et al, 2000). At depth, it might mobilize hot asthenospheric material and contribute to warming and uplift (England and Houseman, 1986;Meissner and Mooney, 1998). In Fig.…”

Section: Discussionmentioning

confidence: 98%

“…According to Dewey et al (1988) and Ratschbacher (1996), one third of the Indian -Asia conversion is accommodated by lateral extrusion. It is suspected that the upper (rigid) part of the crust moves on the shoulder of the hot and weak lower crust because many observations of seismology and heat flow studies indicate a warm and weak lower crust, apparently hot and wet in the south, hot and dry in the north Meissner and Mooney, 1998;Kola-Ojo and Meissner, 2001;Kind et al, 2002). It should be remembered that a temperature of 800 jC does not much weaken the upper mantle, but it is above the solidus of granitic and even gabbroic material (Meissner and Strehlau, 1982), causing a dramatic weakening in a thick crust (e.g., Haines et al, 2003), generating partial melts, possibly partly responsible for the low crustal velocities.…”

Section: Discussionmentioning

confidence: 99%

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About the lithospheric structure of central Tibet, based on seismic data from the INDEPTH III profile

2004

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Signals from 11 shots and 8 earthquakes, and numerous teleseismic events were recorded along the 400-km seismic line INDEPTH III in central Tibet and interpreted together with previous seismic and tectonic data. The abnormal behavior of various mantle phases reveals a complex Moho-transition zone, especially in the northern part of the line, in the Changtang Block, where the lower crust and the mantle show unusually low velocities, a shingled appearance of P n and no low-velocity layer in the upper crust. The strong east -west anisotropy in the Changtang Block is related to an easterly escape movement of the whole lithosphere, facilitated by the warm and weak layers in the lower crust and the upper mantle, bounded apparently by two prominent west -east running fault zones. D

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

About the lithospheric structure of central Tibet, based on seismic data from the INDEPTH III profile

2004

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“…If the rift had been opened by relative rotation of the lithospheric blocks, the extensional regime north of the profile (Figure 1) could have been replaced by a contraction in its vicinity. Also, if the lower lithosphere is mechanically weakened, escape tectonics [Meissner and Mooney, 1998] might have contributed to its additional thickening through a northward horizontal flow.…”

Section: Causes Of the Uppermost Mantle Heterogeneitymentioning

confidence: 99%

Heterogeneity of the uppermost mantle beneath Russian Eurasia from the ultra‐long‐range profile quartz

Морозова¹,

Morozov²,

Smithson³

et al. 1999

J. Geophys. Res.

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“…The blue box shows the location of our study area can be explained by the low mechanical strength of the lower crust. Tomography results also show low-velocity zones in the lower crust (Meissner and Mooney 1998;Galvé et al 2006;Wang et al 2007;Yao et al 2008;Yang et al 2012;Liu et al 2014). Furthermore, small elastic thickness and high Q value of Tibetan plateau both support a weak lower crust for the Tibetan plateau (Jordan and Watts 2005;Wang et al 2007;Bao et al 2011;Zhao et al 2013).…”

Section: Introductionmentioning

confidence: 76%

Analytical and numerical simulations of uplift processes at the Tibet-Sichuan boundary

Peng

Leng

2017

Earthq Sci

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Previous studies have shown that the uplift of Tibetan plateau started in response to the collision of Indian plate and Eurasian plate. During this process, the crust of Tibetan plateau has been greatly thickened which leads to significant elevations. The elevation gradient is extremely large at the east boundary of Tibetan plateau where Longmenshan fault exists, dropping from 4500 to 500 m within a distance of 100 km, while it is more gentle at the south and north sides of Sichuan basin. Such a difference of elevation gradient has been explained with a crustal channel flow model. However, previous crustal flow models consider the thickness of the lower crust as a constant which is highly simplified. Therefore, it is essential to build a more realistic crustal flow model, in which the thickness of the lower crust is variable and dependent on the inflow velocity of crustal materials. Here we build up both analytical and numerical models to study the mechanism and process of the uplift of Tibetan plateau at the eastern boundary. The results of the analytical model show that if the thickness of the lower crust can vary during the uplift process, the lower crustal viscosity of the Sichuan basin needs to be 10 22 Pas to fit the observed elevation gradient. Such a viscosity is one-order magnitude larger than the previous results. Numerical model results further show that the state of stresses at the plateau boundary changes during uplift processes. Such a stress state change may cause the formation of different fault types in the Longmenshan fault area during its uplift history.

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Weakness of the lower continental crust: a condition for delamination, uplift, and escape

Cited by 214 publications

References 54 publications

About the lithospheric structure of central Tibet, based on seismic data from the INDEPTH III profile

About the lithospheric structure of central Tibet, based on seismic data from the INDEPTH III profile

Heterogeneity of the uppermost mantle beneath Russian Eurasia from the ultra‐long‐range profile quartz

Analytical and numerical simulations of uplift processes at the Tibet-Sichuan boundary

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