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

New field observations and 40Ar/39Ar 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 40Ar/39A...

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Bibliographic Details
Published in:Frontiers in Earth Science
Main Authors: Francis J. Sousa, Stephen E. Cox, Sidney R. Hemming, E. Troy Rasbury, Elena Steponaitis, Kevin Hatton, Mae Saslaw, Gregory Henkes, Patricia Princehouse, Natasha S. Vitek, Isaiah Nengo
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-02-01
Subjects:
East Africa rift system
oligocene
hominid evolution
stratigraphy
geochronology
Turkana basin
Online Access:https://www.frontiersin.org/articles/10.3389/feart.2022.799097/full
Description
Summary:New field observations and 40Ar/39Ar 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 40Ar/39Ar 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.
ISSN:2296-6463

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