Please use this identifier to cite or link to this item:
Item metadata
Title: An astronomically-tuned climate framework for hominins in the Turkana Basin
Authors: Joordens, Joséphine C. A.
Vonhof, Hubert B.
Feibel, Craig S.
Lourens, Lucas
Dupont-Nivet, Guillaume
Lubbe, H. J. L. van der
Sier, Mark Jan
Davies, Gareth R.
Kroon, Dick
Keywords: Strontium isotopes;Fish apatite;Olduvai chron;Precession cycles;Aridity refugium
Issue Date: Jul-2011
Publisher: Elsevier
Citation: Earth and Planetary Science Letters, 2011, 307 (1-2), 1-8
Abstract: Understanding the influence of orbital climate cycles on hominin evolution remains a key challenge in paleoanthropology. The two major unresolved issues are: the absence of a climate proxy yielding high-resolution (< 20 kyr) terrestrial climate records, and the lack of age control on hominin fossil occurrences at sufficiently high resolution. Here we present a novel climate proxy, strontium isotope ratios (87Sr/86Sr) of lacustrine fish fossils from the Turkana Basin, that solves these issues by recording orbitally forced variation in summer monsoon intensity over the Ethiopian Highlands. We successfully applied the climate proxy to a ~ 150 kyr time interval of ~ 2 million year old paleolake deposits containing hominin fossils. Existing age control of the studied interval was improved by a new magnetostratigraphic record precisely locating the base of the Olduvai chron (C2n) near the bottom of the sequence. Spectral analysis demonstrates that 87Sr/86Sr variability is primarily determined by precession, which enables us to place hominin fossils in an astronomically-tuned climate framework. The Sr climate proxy is potentially applicable to all hominin-bearing lake deposits in the Turkana Basin, ranging in age from ~ 4.2 to 0.8 million years ago (Ma). Our results demonstrate that between ~ 2 and 1.85 Ma the Turkana Basin remained well-watered and inhabited by hominins even during periods of precession maxima when summer monsoon intensity was lowest. This is in contrast to other basins in the East African Rift System (EARS) that were impacted heavily by precession-forced droughts. We hypothesize that during lake phases, the Turkana Basin was an aridity refugium for permanent-water dependent fauna – including hominins – over the precessional climate cycles.
ISSN: 0012-821X
DOI: 10.1016/j.epsl.2011.05.005
Type: Article
Appears in Collections:Geocronología y Geología

This item is licensed under a Creative Commons License Creative Commons