학술논문
Age-depth model for uppermost Ndutu Beds constrains Middle Stone Age technology and climate-induced paleoenvironmental changes at Olduvai Gorge (Tanzania).
Document Type
Academic Journal
Author
Smedley RK; Department of Geography and Planning, University of Liverpool, Liverpool, L69 7ZT, UK. Electronic address: rachel.smedley@liverpool.ac.uk.; Fenn K; Department of Geography and Planning, University of Liverpool, Liverpool, L69 7ZT, UK.; Stanistreet IG; Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 7ZT, UK; The Stone Age Institute, 1392 W. Dittemore Rd, Gosport, Indiana, 47433, USA.; Stollhofen H; GeoZentrum Nordbayern, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, 91504, Germany.; Njau JK; The Stone Age Institute, 1392 W. Dittemore Rd, Gosport, Indiana, 47433, USA; Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN, 47408, USA.; Schick K; The Stone Age Institute, 1392 W. Dittemore Rd, Gosport, Indiana, 47433, USA.; Toth N; The Stone Age Institute, 1392 W. Dittemore Rd, Gosport, Indiana, 47433, USA.
Source
Publisher: Academic Press Country of Publication: England NLM ID: 0337330 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1095-8606 (Electronic) Linking ISSN: 00472484 NLM ISO Abbreviation: J Hum Evol Subsets: MEDLINE
Subject
Language
English
Abstract
Olduvai Gorge in northern Tanzania is part of a globally important archeological and paleoanthropological World Heritage Site location critical to our understanding of modern human evolution. The Ndutu Beds in the upper part of the geological sequence at Olduvai Gorge represent the oldest unit to yield modern Homo sapiens skeletal material and Middle Stone Age technology. However, the timing of the deposition of the Ndutu Beds is poorly constrained at present, which limits our understanding of the paleoenvironments critical for contextualizing H. sapiens and related technologies in the Olduvai Basin. Using a suite of 15 luminescence ages of sedimentary core samples, combined with Bayesian statistics, this study provides a new higher-resolution age-depth model for the deposition of the uppermost Upper Ndutu and Naisiuiu Beds cored by the Olduvai Gorge Coring Project. The luminescence and modeled ages are presented as ±1 σ uncertainties. The Ndutu Beds intersected by the Olduvai Gorge Coring Project cores are dated to between 117.1 ± 17.9 and 45.3 ± 4.2 ka (between 125.9 ± 26.5 and 45.8 ± 8.2 ka modeled ages), while a probable overlying layer of Naisiusiu Beds dates to 23.7 ± 10.9 to 12.1 ± 1.7 ka (25.7 ± 18.9 ka and 12.0 ± 3.4 ka modeled age). Time-averaged accretion rates are derived during this time: (1) initially low rates (<5 cm ka -1 ) from the bottom of the core at 117.1 ± 17.9 ka up to 95.3 ± 11.1 ka (125.9 ± 26.5 to 95.5 ± 23.3 ka modeled ages); (2) the middle section spanning between 95.3 ± 11.1 and 62.7 ± 5.7 ka (95.5 ± 23.3 to 61.9 ± 10.4 ka modeled ages) with mean rates above 15 cm ka -1 ; and (3) the last 62.7 ± 5.7 ka (61.9 ± 10.4 ka modeled age) where the accretion rate reduces to below 5 cm ka -1 . This reduction can be explained by the evolution of the gorge system that was likely driven by subsidence of the Olbalbal depression and changes in climate, particularly precipitation and resulting lake and base level changes. Older Upper Ndutu and Lower Ndutu Beds are contained within proto-gorges within the modern gorge system.
(Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
(Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)