303-1 The Desert Eyes Project: A Decade and a Half of Research in the Western Desert of Egypt Catalyzed by Professor Mohamed Abdelsalam

Session: Honoring the Late Professor Mohamed Abdelsalam: Outstanding Researcher, Generous Colleague, Legendary Mentor, and Ambassador for the Geosciences In Africa (Posters)

Poster Booth No.: 176

Presenting Author:

Barbara Tewksbury

Authors:

Tewksbury, Barbara J.¹, Tarabees, Elhamy Aly², Mehrtens, Charlotte J.³, Kattenhorn, Simon A.⁴, Hogan, John Patrick⁵, Dokmak, Asmaa⁶, Welch, Robert Marquand⁷

(1) Hamilton College, retired, Deansboro, NY, USA, (2) Geology Department, Damanhour University, Damanhour, Egypt, Arab Rep., (3) University of Vermont, retired, Burlington, VT, USA, (4) University of Hawaii at Hilo, Hilo, HI, USA, (5) Missouri Univ of Science & Technology, GGPE, Rolla, MO, USA, (6) Atmos Energy, Katy, TX, USA, (7) Loyola Marymount University, Los Angeles, CA, USA,

Abstract:

Since 2009, the Desert Eyes Project has investigated bedrock structures in Mesozoic and Paleogene rocks of the Western Desert, Egypt, using a combination of field work, geophysics, and satellite image analysis. The work, catalyzed and enthusiastically supported by late Professor Mohamed Abdelsalam, involved 5 American faculty, 5 Egyptian faculty, 32 American students, and 8 Egyptian students. Results include:

 

Polygonal faults. The Project discovered one of the only polygonal fault systems extensively exposed on land and mapped the system in Cretaceous chalk of the Khoman Formation near Farafra Oasis. The polygonal network of faults is characterized by clusters of dozens of high-angle, mechanically interacting normal faults with grooved fault surfaces and crack-seal calcite veins. The horizontal strain field was essentially isotropic and extensional. Formation of the network involved high pore fluid pressures, fluid escape, and layer-parallel shrinkage (doi.org/10.1130/G36059Y.1).

 

Non-tectonic sag synclines. The Project discovered and mapped an extensive network of narrow, non-tectonic sag synclines exposed in Eocene limestone over an area of ~8000 km² in the Western Desert. The network displays two distinct patterns: 1) synclines outlining polygons 700-2000 m across and 2) N-S zones of synclines spaced 5-10 km apart, connected by WNW-ESE to NW-SE synclines. We suggest that different network patterns reflect different patterns of faults and fractures in underlying strata that conveyed aggressive hypogene fluids upward into limestones, causing dissolution at depth and sag above (doi.org/10.3389/feart.2021.678565).

 

Slip history of E-W faults. In the southeast Western Desert, E-W faults and co-located domes and basins involve Eocene bedrock but have been inferred to also have been active during the Mesozoic. Field work, sample analysis, high-resolution satellite imagery, and burial estimates suggest that Late Mesozoic strike-slip reactivation of basement faults produced domes and basins in step-over regions, followed by late Eocene reactivation producing deformation band systems and extensively linked fault segments (doi.org/10.1016/j.jafrearsci.2017.06.026).

 

Possible mass transport deposits. Bedding surfaces in the Eocene Dungul Formation are extensively exposed on the southernmost Western Desert Limestone Plateau. High-resolution satellite imagery reveals previously unrecognized patterning on bedding surfaces in two stratigraphic horizons. We suggest that these horizons contain mass transport deposits mobilized on a shallow carbonate shelf (doi.org/10.1130/abs/2022AM-379763).

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6730

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