Chronostratigraphy and correlation of the Plio-Pleistocene tephra layers of the Konso Formation, southern Main Ethiopian Rift, Ethiopia

The Plio-Pleistocene Konso Formation is widely exposed in the Konso area lo cated at the southwestern end of the southern sector of the Main Ethiopian Rift. It is known for its rich Acheulean archeological occurrences and abun dant Vertebrate fossils, including those of A. boisei and H, erectus. The f ormation also contains more than 30 tephra layers. The lithologic character ization and major element compositions of discrete glass shards of these te phra, combined with single-crystal Ar-40/Ar-39 dating of seven tuffs, have established the tephrostratigraphy and age range of the 200-m thick formati on. The succession at Konso was deposited between approximately 1.9 and 1.4 Ma and is divided into the Sorobo, Turoha, Kayle, and Karat Members in asc ending stratigraphic order. Two of the Konso tephra are correlative to the Pliocene KBS and the early Pleistocene Chari Tuffs of the Omo-Turkana Basin along the Ethiopian and Kenyan border. This correlation enables precise ti me-controlled comparisons of faunal and archeological remains between the t wo regions. (C) 2000 Elsevier Science Ltd. All rights reserved.