Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 1, 2005 | Published
Journal Article Open

Dynamic topography produced by lower crustal flow against rheological strength heterogeneities bordering the Tibetan Plateau


Dynamic stresses developed in the deep crust as a consequence of flow of weak lower crust may explain anomalously high topography and extensional structures localized along orogenic plateau margins. With lubrication equations commonly used to describe viscous flow in a thin-gap geometry, we model dynamic stresses associated with the obstruction of lower crustal channel flow due to rheological heterogeneity. Dynamic stresses depend on the mean velocity (Ū), viscosity (µ) and channel thickness (h), uniquely through the term µŪ/h^2. These stresses are then applied to the base of an elastic upper crust and the deflection of the elastic layer is computed to yield the predicted dynamic topography. We compare model calculations with observed topography of the eastern Tibetan Plateau margin where we interpret channel flow of the deep crust to be inhibited by the rigid Sichuan Basin. Model results suggest that as much 1500 m of dynamic topography across a region of several tens to a hundred kilometres wide may be produced for lower crustal material with a viscosity of 2 × 10^(18) Pa s flowing in a 15 km thick channel around a rigid cylindrical block at an average rate of 80 mm yr^(−1).

Additional Information

© 2005 RAS. Accepted 2004 December 23. Received 2004 November 30; in original form 2003 September 29. Published: 01 August 2005. The work in this paper was supported by a NSF graduate fellowship to MC, and NSF grants EAR-9814303, EAR-0003571 and EAR-9614970 to LR. JB gratefully acknowledges the financial support of the NSF through Career Grant CTS-0130465. We thank P. Molnar for his constructive review of this manuscript and B. C. Burchfiel, K. Whipple and M. House for their helpful comments and discussion on an earlier version. We also thank Z. Chen, X. Zhang and W. Tang of the Chengdu Institute of Geology and Mineral Resources and M. House for their assistance and expertise with geological research and field work in eastern Tibet.

Attached Files

Published - 162-2-575.pdf


Files (1.3 MB)
Name Size Download all
1.3 MB Preview Download

Additional details

August 19, 2023
August 19, 2023