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WITHDRAWN: Chronostratigraphy of the Baringo-Tugen-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating, magnetostratigraphy, tephrostratigraphy, sequence stratigraphy and Bayesian age modeling

Authors :
Guillaume Dupont-Nivet
Jennifer J. Scott
Alan L. Deino
Andrew S. Cohen
Dominique Garello
C. Brenhin Keller
Mark Jan Sier
John D. Kingston
Berkeley Geochronology Center (BGC)
University of Oxford [Oxford]
Centro Nacional de Investigación sobre la Evolución Humana (CENIEH)
Arizona State University [Tempe] (ASU)
University of Michigan [Ann Arbor]
University of Michigan System
Mount Royal University
Géosciences Rennes (GR)
Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1)
Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)
University of Potsdam
University of Arizona
EAR 1338553, National Science Foundation
International Continental Drilling Program
University of Oxford
Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)
Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
University of Potsdam = Universität Potsdam
Source :
Palaeogeography, Palaeoclimatology, Palaeoecology, Palaeogeography, Palaeoclimatology, Palaeoecology, Elsevier, 2019, 532, pp.109258. ⟨10.1016/j.palaeo.2019.109258⟩, Palaeogeography, Palaeoclimatology, Palaeoecology, 2019, 532, pp.109258. ⟨10.1016/j.palaeo.2019.109258⟩
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

International audience; The Baringo-Tugen-Barsemoi 2013 drillcore (BTB13), acquired as part of the Hominin Sites and Paleolakes Drilling Project, recovered 228 m of fluviolacustrine sedimentary rocks and tuffs spanning a ~3.29–2.56 Ma interval of the highly fossiliferous and hominin-bearing Chemeron Formation, Tugen Hills, Kenya. Here we present a Bayesian stratigraphic age model for the core employing chronostratigraphic control points derived from 40Ar/39Ar dating of tuffs from core and outcrop, 40Ar/39Ar age calibration of related outcrop diatomaceous units, and core magnetostratigraphy. The age model reveals three main intervals with distinct sediment accumulation rates: an early rapid phase from 3.2 to 2.9 Ma; a relatively slow phase from 2.9 to 2.7 Ma; and the highest rate of accumulation from 2.7 to 2.6 Ma. The intervals of rapid accumulation correspond to periods of high Earth orbital eccentricity, whereas the slow accumulation interval corresponds to low eccentricity at 2.9–2.7 Ma, suggesting that astronomically mediated climate processes may be responsible for the observed changes in sediment accumulation rate. Lacustrine transgression-regression events, as delineated using sequence stratigraphy, dominantly operate on precession scale, particularly within the high eccentricity periods. A set of erosively based fluvial conglomerates correspond to the 2.9–2.7 Ma interval, which could be related to either the depositional response to low eccentricity or to the development of unconformities due to local tectonic activity. Age calibration of core magnetic susceptibility and gamma density logs indicates a close temporal correspondence between a shift from high- to low-frequency signal variability at ~3 Ma, approximately coincident the end of the mid-Piacenzian Warm Period, and the beginning of the cooling of world climate leading to the initiation of Northern Hemispheric glaciation c. 2.7 Ma. BTB13 and the Baringo Basin records may thus provide evidence of a connection between high-latitude glaciation and equatorial terrestrial climate toward the end of the Pliocene.

Details

ISSN :
00310182
Volume :
532
Database :
OpenAIRE
Journal :
Palaeogeography, Palaeoclimatology, Palaeoecology
Accession number :
edsair.doi.dedup.....a86eb4c207ad1b1d9aa57da477c62e0e