The field has covered an area of about 3,000 square kilometres (1,200 sq mi) with lava domes, lava flows and volcanic cones[1] such as the shield volcanoes Ras el-Mohor and Ras Tebra. Exposed laccoliths are also common in some parts of the field, such as Kaf El Khalef, Kaf El Tekut, Kaf Mantrus, Kaf el-Tuam and Ras Tuint-Rabib.[5] The location of these vents appears to be controlled by a neighbouring graben and tectonic fractures.[4] The volcanic field developed on a basement formed by Mesozoiclimestones.[2]
Potassium-argon dating has yielded an age of about 12 to 1 million years ago for the field;[1] activity commenced in the Eocene with the basaltic plateau and continued in the late Eocene and later with lava domes and individual volcanoes.[6] Volcanic activity has been subdivided in several separate cycles.[7]
Al-Hafdh, N.M.; Gafeer, A.S. (April 2015). "The petrology and geochemistry of Gharyan volcanic province of NW Libya". Journal of African Earth Sciences. 104: 71–102. doi:10.1016/j.jafrearsci.2014.11.006. ISSN1464-343X.