A million year vegetation history and palaeoenvironmental record from the Lake Magadi Basin, Kenya Rift Valley

V.M. Muiruri, R.B. Owen, T.K. Lowenstein, R.W. Renaut, R. Marchant, S.M. Rucina, A. Cohen, A.L. Deino, M.J. Sier, S. Luo, K. Leet, C. Campisano, N.M. Rabideaux, D. Deocampo, Chuan Chou Shen, A. Mbuthia, B.C. Davis, W. Aldossari, C. Wang

Research output: Contribution to journalArticlepeer-review

Abstract

This study examines a one-million-year pollen record from a 194-m-long Lake Magadi core (HSPDP-MAG14-2A) in the south Kenya Rift Valley. The pollen indicate a general trend through the last 740 kyr from wetter conditions to generally drier environments. Grassland dominated with less common Podocarpus and Cyperaceae in a sparse flora between 1000 and 740 ka. Poaceae, woodland and herbaceous plants are common through the remaining core and abundant between 740 and 528 ka and after 200 ka. Pollen diversity increased after 200 ka. Podocarpus and Cyperaceae reached a peak abundance at ~575 ka with a subsequent decline that suggests a progressive increase in aridity, interrupted by wetter intervals. Podocarpus-dominated forests expanded and contracted many times during the Quaternary and document an anti-phased relationship with data from Lake Malawi. Similar anti-phased correlations are noted for herbaceous plants, suggesting that the two basins responded differently to the same climate or were influenced by contrasting climate regimes. Increases in macrocharcoal correlate with increasing pollen abundance and suggest wetter conditions. Data from the Magadi, Koora and Olorgesailie basins indicate similar trends and a dominant climate control on vegetation and habitats. Large lakes characterised all three basins at 740–528 ka with climate subsequently becoming drier, but with many wetter intervals. At various times the lakes expanded, contracted and dried out, except at Lake Magadi where spring inflows maintained lacustrine conditions through the late Quaternary. Faulting also contributed to fragmentation of the landscape and formation of a mosaic of habitats. An especially intense period of aridity at ~528–392 ka coincided with extinction of many large-bodied mammals and may have helped to drive a change from the use of Acheulean hand axes to the production of Middle Stone Age tools by 320 ka. After 200 ka pollen diversity increased substantially with a mix of montane, riparian and dry forest associations that were present in varying amounts through to ~4.2 ka at the core top. © 2021 Elsevier B.V.
Original languageEnglish (US)
Article number110247
Number of pages16
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume567
DOIs
StatePublished - 2021

Bibliographical note

Funding Information:
The Hominin Sites and Paleolakes Drilling Project was funded by grants from the ICDP and US-NSF (EAR-1123942, BCS-1241859, BCS-1241790, EAR-1322017 and EAR-1338553). Pollen research was supported by the Hong Kong Research Grants Council. Permits and research support were provided by the National Museums of Kenya, the Kenyan National Council for Science and Technology, the Kenyan Ministry of Mines and the National Environmental Management Authority of Kenya. We also thank DOSECC Exploration Services for drilling support and the US National Lacustrine Core Facility (LacCore) for assistance with core curation and logging. Tata Chemicals and the Magadi County Council provided local assistance. This is publication #32 of the Hominin Sites and Paleolakes Drilling Project.

Funding Information:
The Hominin Sites and Paleolakes Drilling Project was funded by grants from the ICDP and US-NSF ( EAR-1123942 , BCS-1241859 , BCS-1241790 , EAR-1322017 and EAR-1338553 ). Pollen research was supported by the Hong Kong Research Grants Council . Permits and research support were provided by the National Museums of Kenya , the Kenyan National Council for Science and Technology , the Kenyan Ministry of Mines and the National Environmental Management Authority of Kenya . We also thank DOSECC Exploration Services for drilling support and the US National Lacustrine Core Facility (LacCore) for assistance with core curation and logging. Tata Chemicals and the Magadi County Council provided local assistance. This is publication #32 of the Hominin Sites and Paleolakes Drilling Project.

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Climate change
  • Hominin evolution
  • Palaeolakes
  • Podocarpus
  • Pollen
  • Quaternary

Continental Scientific Drilling Facility tags

  • HSPDP-MAG

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