Magnetochronology and age models of deposition of the Melka Kunture stratigraphic sequence (Upper Awash, Ethiopia) and age assessments of the main archeological levels therein contained

Abstract

We present new magnetostratigraphic results from the Melka Kunture sedimentary sequence outcropping along the Gombore and Garba gullies in the Upper Awash Valley of Ethiopia that provide a new temporal framework for human presence in this area of the Ethiopian plateau in the Pleistocene. We obtained a time-diagnostic sequence of normal and reverse polarity magnetozones representing a relatively continuous magnetochronologic record extending from the Brunhes Chron at the top to the Olduvai Subchron or possibly the Reunion Subchron at the base, assembled from 9 stratigraphic sections correlated in a regional lithostratigraphic context. By integrating our chronology provided by paleomagnetism with 40Ar/39Ar dating from the literature, we generated simple yet reliable and testable age models of deposition for the Melka Kunture sedimentary sequence that we used to estimate the mean ages of the main archeological levels therein contained that resulted ranging from ∼0.6 Ma to ∼2.1 Ma thus representing altogether one of the most persistent and prolonged records of human presence of the entire African continent.