AUTHOR=Sousa Francis J. , Cox Stephen E. , Hemming Sidney R. , Rasbury E. Troy , Steponaitis Elena , Hatton Kevin , Saslaw Mae , Henkes Gregory , Princehouse Patricia , Vitek Natasha S. , Nengo Isaiah 

TITLE=New Discovery of Oligocene Strata in the Topernawi Formation, Turkana County, Kenya

JOURNAL=Frontiers in Earth Science

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.799097

DOI=10.3389/feart.2022.799097

ISSN=2296-6463

ABSTRACT=<p>New field observations and <sup>40</sup>Ar/<sup>39</sup>Ar geochronology reveal that the Topernawi Formation of the Ekitale Basin, northern Turkana Depression, Turkana County, Kenya was deposited entirely during the Oligocene between 29.7 ± 0.5 Ma and 29.24 ± 0.08 Ma. These bracketing ages are determined via new <sup>40</sup>Ar/<sup>39</sup>Ar geochronology on a basaltic lava flow at the base of the section and a felsic ignimbrite near the top. A newly discovered basal unit and interbedded lava flow result in a new total sedimentary thickness of 92 m. The Topernawi Formation is the oldest dated syn-rift sedimentary section in the northern Turkana Depression.</p>