PP016-0001
Geochronology and Stratigraphy of the Ekitale Basin, Turkana County, Kenya

Wednesday, 9 December 2020
Poster
Francis Sousa, Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, OR, United States, Stephen Cox, Lamont-Doherty Earth Observatory, Palisades, United States, Sidney R Hemming, Lamont-Doherty Earth Observatory, Palisades, NY, United States, Kevin Hatton, Stony Brook University, Stony Brook, United States, Troy Rasbury, Stony Brook University, Stony Brook, NY, United States, Elena Steponaitis, Tulane University, New Orleans, LA, United States; Tulane University, Department of Earth and Environmental Sciences, New Orleans, LA, United States and Patricia Princehouse, Case Western Reserve University, Cleveland, United States
Abstract:
New field and geochronologic data from Topernawi Gorge, Turkana County, Kenya increases the published stratigraphy of the Ekitale Basin by more than ten percent and changes the age of the base of the section to 29.1 +/- 0.2 Ma. In addition to this new date for the base of the section, we report a new Ar-Ar date on a newly discovered interbedded basaltic lava flow (27.7 +/- 0.3 Ma), that provides bracketing ages on the lowest ~10 meters of Ekitale Basin strata. Combined with published Ar-Ar dates on mafic dikes that cross-cut the upper units of the section (Ragon et al. 2018), this new data requires that the entirety of the Ekitale Basin section was deposited between ~29 Ma and 25 Ma. This refined geochronology and stratigraphy provides new constrains on the timing and magnitude of Paleogene extensional activity in the East African Rift zone, as well as new constraints on the chronology of the fossil bearing strata in the upper units of Ekitale Basin.

Ragon et al. (2018) DOI: 10.1002/gj.3339

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