Lattice-particle simulation of stress patterns in a Rwenzori-type rift transfer zone

Sachau, T., Koehn, D. and Passchier, C. (2011) Lattice-particle simulation of stress patterns in a Rwenzori-type rift transfer zone. Journal of African Earth Sciences, 61(4), pp. 286-295. (doi: 10.1016/j.jafrearsci.2011.08.006)

Abstract

A new 3D spring lattice computer model has been developed and used to calculate the stress-field in the vicinity of a rift transfer zone. The numerical setup is based on the Rwenzori block, a transfer zone in the Western Branch of the East African Rift Valley. The study has two closely related, yet independent aims: primarily to gain insight into the pattern and the causes of the stress field in the Rwenzori area. The second aim is the evaluation of the model itself, based on a comparison of the model results with local geological structures. <br/> The simulations calculate the stress in the brittle part of the crust, at the topographic surface and at a depth of 10 km. The model does therefore not rely on the rate of the continental extension, but only on the amount. The generated stress maps display the maximum and minimum principal normal stress. The stress is calculated for a total extension of 7.5 km, a value based on common estimates for the local rift extension. <br/> The local stress field is created by the interplay of the plate driven far-field stress and the mechanics of the rift system. The propagation of the rift system leads thus to stress rotations and to characteristic stress patterns. An important mechanism is lithospheric bending caused by rift flank uplift, which reverses the far field stress in rift vicinity. <br/> The stress-field resulting from the simulations explains several previously unexplained structural features encountered in the Rwenzori block.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Koehn, Dr Daniel
• Authors: Sachau, T., Koehn, D., and Passchier, C.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Journal of African Earth Sciences
• ISSN: 1464-343X