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Article
Mantle Structure beneath the Incipient Okavango Rift Zone in Southern Africa
Geosphere
  • Youqiang Yu
  • Kelly H. Liu, Missouri University of Science and Technology
  • Zhouchuan Huang
  • Dapeng Zhao
  • Cory A. Reed
  • Moikwathai Moidaki
  • Jianshe Lei
  • Stephen S. Gao, Missouri University of Science and Technology
Abstract

Numerous investigations of the mature segments of the East African rift system (EARS) have significantly improved our understanding of the structure and processes associated with well-developed continental rifts. In contrast, knowledge of rifting processes at their early stage is still significantly limited. Here we present results from a teleseismic P-wave tomography investigation of the incipient Okavango rift zone (ORZ), which is located at the southwestern terminus of the EARS. P-wave relative travel-time residuals recorded by 17 recently deployed portable seismic stations were manually picked and inverted for three-dimensional upper-mantle and mantle transition-zone tomographic images beneath the ORZ and its adjacent areas. High-velocity anomalies probably representing cratonic lithosphere are visible under the Congo and Kalahari cratons, extending to depths of ∼250–350 km. The tectonic boundary of the Congo craton is observed along the western edge of the ORZ. A localized low-velocity anomaly of about –1% in magnitude is revealed in the upper asthenosphere beneath the ORZ, which is interpreted to represent decompression melting induced by lithospheric thinning. The results support the notion that the initiation and early-stage development of the ORZ are mostly due to lithospheric stretching resulted from the relative motion between the Archean Congo and Kalahari cratons along preexisting ancient orogenic zones.

Department(s)
Geosciences and Geological and Petroleum Engineering
Research Center/Lab(s)
Center for High Performance Computing Research
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2016 Geological Society of America, All rights reserved.
Publication Date
11-1-2016
Citation Information
Youqiang Yu, Kelly H. Liu, Zhouchuan Huang, Dapeng Zhao, et al.. "Mantle Structure beneath the Incipient Okavango Rift Zone in Southern Africa" Geosphere Vol. 13 (2016) ISSN: 1553-040X
Available at: http://works.bepress.com/kelly-liu/49/