--> Abstract: Tectonic Inversion of Kattaniya Basin, North Western Desert, Egypt, by Farouk Metawalli, John Pigott, and Ali M. Bakr; #90072 (2007)

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Tectonic Inversion of Kattaniya Basin, North Western Desert, Egypt

Farouk Metawalli1, John Pigott2, and Ali M. Bakr3
1Helwan University, Cairo, Egypt
2University of Oklahoma, Norman, OK
3Apache Oil Company, Cairo, Egypt

The tectonic subsidence history of the Kattaniya Basin of the northern Western Desert of Egypt reveals two major episodes: an extensional subsiding phase which initiated at the end of the Early Cretaceous and a shortening uplifting phase which began during the Miocene. Integration of the subsurface information with the surrounding regional geology of the Qarun Region provides insight into the fault mechanical stratigraphy as well as allows comparison of the strain history of this basin to basins that have experienced inversion elsewhere in the world.
During the extensional phase, NE-SW trending faults separated the basin into half-grabens. Thermal modeling suggests potential source rock units down dip reached maturity with both oil and gas generation confirmed in the Turonian and Cenomanian reservoirs of the intra Kattaniya, El Gindi, and Qarun inverted sub-basins. During crustal shortening, existing faults were either reactivated or new ones formed owing to either to their orientation, their sliding friction coefficient, and/or their state of stress. Flexuring and folding of the sediment cover generally occurred prior to reactivation of the faults. The reverse slip movement first occurred at depth for these faults and became locked at steeply-dipping upper levels. Propagation of the slip movement along the upper level of the fault and into the sediment cover was greatly a function of shortening. Reactivation of some steeply dipping faults may have nucleated segments of large strike slip faults.
However, whether a particular inherited fault system can accommodate a new stress field appears to differ in that convergent strike-slips tend to reactivate relatively high angle normal faults (which become reverse faults) whereas such faults tend to lock when subjected to more direct pure shear which tends to create lower angle faults for stress accommodation.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece