EGU22-1100
https://doi.org/10.5194/egusphere-egu22-1100
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Paleoenvironmental reconstruction in East Africa at a critical period of hominin dispersion out-of-Africa (150-80 kyr)

Cecile A. Porchier1,2, Mark A. Maslin1, Tom Hill3,2, David M. Williams4, Eileen Cox4, Anson W. Mackay1, George E.A. Swann5, and Melanie J. Leng6,7
Cecile A. Porchier et al.
  • 1Department of Geography, University College London, London, United Kingdom – (cecile.porchier.18@ucl.ac.uk)
  • 2Department of Earth Sciences, Natural History Museum, London, United Kingdom
  • 3PalaeoEnvironmental Research and Consultancy Services Ltd (PERCS), United Kingdom
  • 4Department of Life Sciences, Natural History Museum, London, United Kingdom
  • 5Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom
  • 6National Environmental Isotope Facility, British Geological Survey, Nottingham, United Kingdom
  • 7Centre for Environmental Geochemistry, School of Biosciences, University of Nottingham, Nottingham, United Kingdom

Climate may have played a critical role in early hominin evolution and dispersion, with rapid changes from humid to hyper-arid observed in East African palaeoclimate records. Many studies show linkages between these climate changes and hominin speciation and dispersion; however, few of them have focused on annual to decadal climate variability. This new study presents paleoenvironmental records (diatom assemblages and oxygen isotopes in diatom biogenic silica, d18Odiatom) from the Ol Njorowa Gorge in Kenya. The study site is located west of the African Rift Valley, from where important hominin dispersals are believed to have taken place. The study site preserves a stratigraphic record of interbedded diatomite beds spanning a key period of theorised hominin dispersals; 150,000 to 80,000 years ago. In this study, diatom assemblages and d18Odiatomrecords are used to understand past changes in moisture and precipitation patterns over East Africa as well as changes in lake water chemistry. d18Odiatom has been used in both lacustrine and oceanic settings since the early 2000s. It is however an under-utilised proxy that holds great potential, especially for diatomites from exposed lake beds where carbonate material is scarce or inexistant. The study also uses high resolution scanning XRF data from diatomite blocks to develop an age model for the diatomite beds at an annual timescale.

How to cite: Porchier, C. A., Maslin, M. A., Hill, T., Williams, D. M., Cox, E., Mackay, A. W., Swann, G. E. A., and Leng, M. J.: Paleoenvironmental reconstruction in East Africa at a critical period of hominin dispersion out-of-Africa (150-80 kyr), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1100, https://doi.org/10.5194/egusphere-egu22-1100, 2022.

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