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

QUATERNARY SCIENCE REVIEWS

卷:215

Article

Deino, A. L.¹  Dommain, R.^2,3  Keller, C. B.^1,4  Potts, R.²  Behrensmeyer, A. K.⁵  Beverly, E. J.⁶  King, J.⁷  Heil, C. W.⁷  Stockhecke, M.⁸  Brown, E. T.⁸  Moerman, J.²  deMenocal, P.^9,10 

[1] Berkeley Geochronol Ctr, 2455 Ridge Rd, Berkeley, CA 94709 USA

[2] Smithsonian Inst, Human Origins Program, Natl Museum Nat Hist, Washington, DC 20013 USA

[3] Univ Potsdam, Inst Geosci, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany

[4] Dartmouth Coll, Dept Earth Sci, Hanover, NH 03755 USA

[5] Smithsonian Inst, Dept Paleobiol, Natl Museum Nat Hist, Washington, DC 20013 USA

[6] Univ Houston, Dept Earth & Atmospher Sci, Sci & Res Bldg 1,3507 Cullen Blvd,Rm 312, Houston, TX 77204 USA

[7] Univ Rhode Isl, Grad Sch Oceanog, South Ferry Rd, Narragansett, RI 02882 USA

[8] Univ Minnesota, Large Lakes Observ, Duluth, MN 55812 USA

[9] Columbia Univ, Dept Earth & Environm Sci, Palisades, NY 10964 USA

[10] Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA

关键词: Pleistocene;    Paleolimnology;    East Africa;    Sedimentology;    Radiogenic isotopes;    Bayesian modeling;    paleosol;    Tephrostratigraphy;    Magnetostratigraphy;    Kenya Rift;   

DOI  :  10.1016/j.quascirev.2019.05.009

来源: Elsevier

【 摘 要 】

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 OL012-1A 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 OL012-1A. Firstly, chronostratigraphic control points for the core were established based on 4 Ar/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, nonlinear 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 inter connectivity of the Koora Basin to adjacent areas and sources of volcanism. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

Free