Keywords and Phrases
East African Rift System; fault Growth; Fault Height/Length Profiles; Okavango Rift Zone; Pore Fluid Pressure; Tectonic Inheritance
"Integrated geophysical, remote sensing, and field investigations of the Okavango Rift Zone (ORZ), Botswana indicate that a feedback between optimum-oriented basement structures and fluid flow influence the nucleation and growth of continental rifts in their incipient stages. The ORZ, the youngest rift of the East African Rift System, occurs within a Proterozoic inter-cratonic suture zone - the NE-trending Precambrian Damara/Ghanzi-Chobe orogenic belts. The Pleistocene to Holocene ORZ forms a ~450 km long and ~100 km wide half-graben bounded by NE-trending normal faults. Basement units within the Damara/Ghanzi-Chobe orogenic belts exhibit a well-developed NE-trending linear fabric (045-065) defined by parallel limbs of tight folds. The Tsau - Chobe fault system nucleated along the Proterozoic tectonic sutures defining the location of the embryonic ORZ. The initial length of the rift was established first by the Tsau-Chobe master-border fault as ORZ faults have abnormally low D/L relationships as a result of failure along favorably oriented preexisting mechanical strength anisotropies in the crust. Fluid circulation within fault zones reduces the shear stress necessary to reactivate these faults. Subsequent slip events trigger a pore fluid wave that promotes along strike propagation of the fault with low displacement. This creates a positive feedback in which fewer, longer, faults suppress nucleation of new faults. Eventually these faults develop strong cohesive fault rocks, and are abandoned in favor of forming new faults along planar strength anisotropies into the Ghanzi-Chobe basement, widening the ORZ in a southeast direction"--Abstract, page iv.
Hogan, John Patrick
Abdel Salam, Mohamed G.
Gao, Stephen S.
Geosciences and Geological and Petroleum Engineering
Ph. D. in Geology and Geophysics
National Science Foundation (U.S.)
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- The role of crustal strength anisotropies in strain localization during incipient continental rifting: An example from the Okavango Rift Zone, Botswana
- The role of fluid-enhanced tectonic inheritance in continental rifting
xvi, 122 pages
© 2016 Angelica Alvarez Naranjo, All rights reserved.
Dissertation - Open Access
Electronic OCLC #
Alvarez Naranjo, Angelica, "The role of pre-existing basement fabrics in the initiation of continental rifting: The Okavango Rift Zone, Botswana" (2016). Doctoral Dissertations. 2642.