Thermal and mechanical development of the East African Rift System

The deep basins, uplifted flanks, and volcanoes of the Western and Kenya rift systems have developed along the western and eastern margins of the 1300 km-wide East African plateau. Structural patterns deduced from field, Landsat, and geophysical studies in the Western rift reveal a series of asymmetric basins bounded by approximately 100 kmlong segments of the border fault system. These basins are linked by oblique-slip and strike-slip faults cross-cutting the rift valley. Faults bounding the Kenya and Western rift valleys delineate two north-south-trending, 40-75 km wide zones of crustal extension, and little or no crustal thinning has occurred beneath the uplifted flanks or the central plateau. In the Western rift, volcanism in Late Miocene time began prior to or concurrent with basinal subsidence, followed by rift flank uplift. Individual extensional basins developed diachronously, and basinal propagation may give rise to the along-axis segmentation of the rift valley. The coherence between gravity and topography data indicates that the mechanical lithosphere beneath the two rift valleys has been weakened relative to the central plateau and adjacent cratonic regions. Gravity and topography data at wavelengths corresponding to the overcompensated East African plateau can be explained by density variations within the upper mantle that are dynamically maintained.

Department dc:contributor.department

Joint Program in Oceanography

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1988

Author dc:creator

• Ebinger, Cynthia Joan

Advisor dc:contributor.advisor

• Leigh H. Royden.

• Joint Program in Oceanography.
• Earth, Atmospheric, and Planetary Sciences.
• Woods Hole Oceanographic Institution.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/53531

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/53531