Chronostratigraphic model of a high-resolution drill core record of the past million years from the Koora Basin, south Kenya Rift

Overcoming the difficulties of variable sedimentation rate and hiatuses

the Olorgesailie Drilling Project Scientific Team

Research output: Contribution to journalArticle

Abstract

The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OLO12-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OLO12-1A. Firstly, chronostratigraphic control points for the core were established based on 40Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, non-linear depositional environments: 1)correcting for variable rates of deposition, 2)accommodating hiatuses, and 3)quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the interconnectivity of the Koora Basin to adjacent areas and sources of volcanism.

Original languageEnglish (US)
Pages (from-to)213-231
Number of pages19
JournalQuaternary Science Reviews
Volume215
DOIs
StatePublished - Jul 1 2019

Fingerprint

sedimentation rate
Kenya
basins
drilling
basin
lithostratigraphy
tephra
volcanic activity
trachyte
Brunhes chron
magnetic reversal
terrestrial environment
hiatus
East Africa
social stratum
aquatic environment
Eastern Africa
paleosol
depositional environment
volcanism

Keywords

  • Bayesian modeling
  • East Africa
  • Kenya Rift
  • Magnetostratigraphy
  • Paleolimnology
  • Pleistocene
  • Radiogenic isotopes
  • Sedimentology
  • Tephrostratigraphy
  • paleosol

Cite this

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title = "Chronostratigraphic model of a high-resolution drill core record of the past million years from the Koora Basin, south Kenya Rift: Overcoming the difficulties of variable sedimentation rate and hiatuses",
abstract = "The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OLO12-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OLO12-1A. Firstly, chronostratigraphic control points for the core were established based on 40Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, non-linear depositional environments: 1)correcting for variable rates of deposition, 2)accommodating hiatuses, and 3)quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the interconnectivity of the Koora Basin to adjacent areas and sources of volcanism.",
keywords = "Bayesian modeling, East Africa, Kenya Rift, Magnetostratigraphy, Paleolimnology, Pleistocene, Radiogenic isotopes, Sedimentology, Tephrostratigraphy, paleosol",
author = "{the Olorgesailie Drilling Project Scientific Team} and Deino, {A. L.} and R. Dommain and Keller, {C. B.} and R. Potts and Behrensmeyer, {A. K.} and Beverly, {E. J.} and J. King and Heil, {C. W.} and M. Stockhecke and Brown, {Erik T} and J. Moerman and P. deMenocal",
year = "2019",
month = "7",
day = "1",
doi = "10.1016/j.quascirev.2019.05.009",
language = "English (US)",
volume = "215",
pages = "213--231",
journal = "Quaternary Science Reviews",
issn = "0277-3791",
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T1 - Chronostratigraphic model of a high-resolution drill core record of the past million years from the Koora Basin, south Kenya Rift

T2 - Overcoming the difficulties of variable sedimentation rate and hiatuses

AU - the Olorgesailie Drilling Project Scientific Team

AU - Deino, A. L.

AU - Dommain, R.

AU - Keller, C. B.

AU - Potts, R.

AU - Behrensmeyer, A. K.

AU - Beverly, E. J.

AU - King, J.

AU - Heil, C. W.

AU - Stockhecke, M.

AU - Brown, Erik T

AU - Moerman, J.

AU - deMenocal, P.

PY - 2019/7/1

Y1 - 2019/7/1

N2 - The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OLO12-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OLO12-1A. Firstly, chronostratigraphic control points for the core were established based on 40Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, non-linear depositional environments: 1)correcting for variable rates of deposition, 2)accommodating hiatuses, and 3)quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the interconnectivity of the Koora Basin to adjacent areas and sources of volcanism.

AB - The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OLO12-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OLO12-1A. Firstly, chronostratigraphic control points for the core were established based on 40Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, non-linear depositional environments: 1)correcting for variable rates of deposition, 2)accommodating hiatuses, and 3)quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the interconnectivity of the Koora Basin to adjacent areas and sources of volcanism.

KW - Bayesian modeling

KW - East Africa

KW - Kenya Rift

KW - Magnetostratigraphy

KW - Paleolimnology

KW - Pleistocene

KW - Radiogenic isotopes

KW - Sedimentology

KW - Tephrostratigraphy

KW - paleosol

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U2 - 10.1016/j.quascirev.2019.05.009

DO - 10.1016/j.quascirev.2019.05.009

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SP - 213

EP - 231

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

SN - 0277-3791

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