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Tectonic History of the Osbourn Spreading Center and Dynamic Subsidence of the Congo Basin


Downey, Nathan John (2009) Tectonic History of the Osbourn Spreading Center and Dynamic Subsidence of the Congo Basin. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/MXQF-GY83.


This is a thesis in two parts. First is the presentation of a new technique by which it is possible to constrain tectonic models of oceanic regions which are devoid of magnetic reversal anomalies. I applied this technique to the Osbourn region of the Southwest Pacific and determined the tectonic history of the Cretaceous Osbourn spreading center. The results of this analysis showed that the Osbourn Trough, although an extinct spreading center, was not part of the Cretaceous Pacific-Phoenix spreading center. The second part of this thesis involves study of the cratonic Congo sedimentary basin. I created instantaneous dynamic models of the Congo basin that are strongly constrained by observation and which demonstrate that the most recent subsidence event of the basin has a mantle dynamic origin. These models constrain the density structure of the upper mantle beneath the Congo. In addition, I examined geologic data that constrain the time-dependent history of the Congo basin in an attempt to determine the subsidence mechanism of cratonic sedimentary basins.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Congo basin; Dynamic topography; Osbourn Trough; Plate tectonics
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Stock, Joann M. (advisor)
  • Gurnis, Michael C. (co-advisor)
  • Clayton, Robert W. (co-advisor)
  • Simons, Mark (co-advisor)
Thesis Committee:
  • Avouac, Jean-Philippe (chair)
  • Helmberger, Donald V.
  • Heaton, Thomas H.
  • Tromp, Jeroen
Defense Date:21 August 2008
Record Number:CaltechETD:etd-08282008-093820
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3260
Deposited By: Imported from ETD-db
Deposited On:10 Sep 2008
Last Modified:12 Nov 2021 19:45

Thesis Files

PDF (NJD_Thesis_Final.pdf) - Final Version
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