Koobi Fora encompasses a small depocenter , underlain by Pliocene basalts and filled with nearly 600 meters of Pliocene-Pleistocene sediments , dating from about four-million to one-million years ago .
Koobi Fora is underlain by Pliocene basalts and filled with nearly 600 meters of Pliocene-Pleistocene sediments , dating from about four-million to one-million years ago .