MAGNETIC AND GRAVITY STUDY OF AL KUFRA BASIN, SOUTH EASTERN LIBYA

Although Libya, located at the northern extreme of the African continent, has relatively simple surface geology, it has a complex subsurface geology and geological history caused by several tectonic cycles including the Caledonia, Hercynian and Alpine orogenies. These tectonic cycles has yielded a complex crustal structure that is composed of a series of basins and uplifts. As a result, a total of seven sedimentary basins were developed and were separated by intervening uplifts.

Gravity and magnetic anomaly maps, when constrained by geological information has the capability of providing regional information on the structure of sedimentary basins. While gravity anomalies can provide information on the sedimentary units and the Precambrian basement, these same units commonly lack significant magnetization and thus magnetic anomalies usually only provide information on the underlying Precambrian crystalline basement.

This study represents a comprehensive analysis of the Al Kufra basin using magnetic and gravity data constrained by subsurface geological information. The Al Kufra Basin is bounded to the East by the Al Awaynat High, to the west by the Tibesti High and to the north by the Tazerbo (Dalma) High.

Primary results suggest the presence of three primary basement terrains: 1) a NE-SW oriented structural trend with generally high amplitude analytic signals named the Al Awaynat-East Al Kufra terrain. This terrain is the site of NE-SW Caledonian and Hercynian arching; 2) the Central Al Kufra terrain which is characterized by low analytic signal amplitudes and a strong NE-SW structural trend; and 3) The West Al Kufra-East Tibesti-South Siwa terrain which is characterized by high amplitude analytic signals and has N-S and NE-SW trending structural elements. This terrain was the site of Late Permian-Early Triassic arching.