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

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

doi:10.3389/feart.2022.799097

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

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

Stony Brook University, SUNY Oswego

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

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.

Original language	English
Article number	799097
Journal	Frontiers in Earth Science
Volume	10
DOIs	https://doi.org/10.3389/feart.2022.799097
State	Published - Feb 3 2022

Keywords

East Africa rift system
Turkana basin
Turkana depression
geochronology
hominid evolution
oligocene
stratigraphy

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10.3389/feart.2022.799097

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

abstract = "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.",

keywords = "East Africa rift system, Turkana basin, Turkana depression, geochronology, hominid evolution, oligocene, stratigraphy",

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

note = "Publisher Copyright: Copyright {\textcopyright} 2022 Sousa, Cox, Hemming, Rasbury, Steponaitis, Hatton, Saslaw, Henkes, Princehouse, Vitek and Nengo.",

year = "2022",

month = feb,

day = "3",

doi = "10.3389/feart.2022.799097",

language = "English",

volume = "10",

journal = "Frontiers in Earth Science",

issn = "2296-6463",

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TY - JOUR

T1 - New Discovery of Oligocene Strata in the Topernawi Formation, Turkana County, Kenya

AU - Sousa, Francis J.

AU - Cox, Stephen E.

AU - Hemming, Sidney R.

AU - Rasbury, E. Troy

AU - Steponaitis, Elena

AU - Hatton, Kevin

AU - Saslaw, Mae

AU - Henkes, Gregory

AU - Princehouse, Patricia

AU - Vitek, Natasha S.

AU - Nengo, Isaiah

PY - 2022/2/3

Y1 - 2022/2/3

N2 - 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.

AB - 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.

KW - East Africa rift system

KW - Turkana basin

KW - Turkana depression

KW - geochronology

KW - hominid evolution

KW - oligocene

KW - stratigraphy

UR - https://www.scopus.com/pages/publications/85124889448

U2 - 10.3389/feart.2022.799097

DO - 10.3389/feart.2022.799097

M3 - Article

SN - 2296-6463

VL - 10

JO - Frontiers in Earth Science

JF - Frontiers in Earth Science

M1 - 799097

ER -

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

Abstract

Keywords

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