Possible Impact Structures in Saudi Arabia
Neville, Allen S.1; Afifi, Abdulkader M.1; Cook, Douglas J.*1
(1) Exploration, Saudi Aramco, Dhahran, Saudi Arabia.
Five isolated circular structures in the subsurface of the Arabian platform are identified as possibly due to meteorite impacts. Three of these structures (Saqqar, Jalamid, and Banat Baqr) are located in the northern Nafud basin, while the Hamidan and Zaynan structures are located in the Rub’ Al Khali basin. On seismic data, these structures appear as circular features with central uplifts surrounded by circular rims whose diameters range between 4 and 30 kilometers. The structural deformation of the central uplift decreases and disappears with depth. In addition, three of these structures have circular magnetic and/or gravity anomalies. Initial study of samples from wells drilled in three of these structures did not reveal evidence of shock metamorphism except for possible planar deformation lamellae in quartz from a core in the Saqqar structure. Their geologic setting makes it unlikely that these structures formed as salt diapirs, mud diapirs or magma intrusions, and an impact origin is the most plausible.
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain