An age for the Korath Range, Ethiopia and the viability of 40Ar/39Ar dating of kaersutite in Late Pleistocene volcanics

• We establish an age for the Korath Range, Ethiopia.
• We evaluate the influence of the range on major rivers in Omo valley.
• New weighted mean age is consistent with previous estimates.
• 40Ar/39Ar dating of Late Pleistocene kaersutite can be successful.

The Korath Range is the northernmost of five Quaternary volcanic fields along the axis of the Turkana rift of northern Kenya and southern Ethiopia. It is located within the Omo River valley of Ethiopia, a culturally diverse region that contains abundant Plio-Pleistocene human remains, which have been essential to refining our understanding of hominid evolution. Yet, very little geochronologic information is available for the Korath Range. We have undertaken 40Ar/39Ar incremental heating experiments, using two techniques, on kaersutite phenocrysts from a pyroclastic flow and obtained a weighted mean age of 91 ± 15 ka (2σ). The results, although imprecise, suggest that 40Ar/39Ar geochronology of these Ti-rich amphiboles can yield useful age information.