Abstract
Lake Magadi is an internally drained, saline and alkaline terminal sump in the southern Kenya Rift. Geochemistry of samples from an ∼200 m core representing the past ∼1 m.y. ofthe lake’s history shows some of the highest concentrations of transition metals and metalloidsever reported from lacustrine sediment, including redox-sensitive elements molybdenum,arsenic, and vanadium. Elevated concentrations of these elements represent times when thelake’s hypolimnion was euxinic—that is, anoxic, saline, and sulfide-rich. Euxinia was commonafter ca. 700 ka, and after that tended to occur during intervals of high orbital eccentricity.These were likely times when high-frequency hydrologic changes favored repeatedepisodes of euxinia and sulfide precipitation. High-amplitude environmental fluctuations atpeak eccentricity likely impacted water balance in terrestrial habitats and resource availabilityfor early hominins. These are associated with important events in human evolution,including the first appearance of Middle Stone Age technology between ca. 500 and 320 kain the southern Kenya Rift
| Original language | English (US) |
|---|---|
| Pages (from-to) | 42-47 |
| Number of pages | 6 |
| Journal | Geology |
| Volume | 50 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2022 |
Bibliographical note
Funding Information:Funding for the Hominin Sites and Paleolakes Drilling Project (HSPDP) was from the International Continental Scientific Drilling Program (ICDP) and U.S. National Science Foundation (grants EAR-1123942, BCS-1241859, BCS-1241790, EAR-1322017, EAR-1338553, and 1349599) and the Hong Kong Research Grants Council. U-series dating was supported by grants of the Ministry of Education and Ministry of Science and Technology of Taiwan (Republic of China) and National Taiwan University. We thank the National Museums of Kenya, the Kenyan National Council for Science and Technology, the Kenyan Ministry of Mines, the National Environmental
Funding Information:
Funding for the Hominin Sites and Paleolakes Drilling Project (HSPDP) was from the International ContinentalScientific Drilling Program (ICDP) and U.S.National Science Foundation (grants EAR-1123942,BCS-1241859, BCS-1241790, EAR-1322017, EAR-1338553, and 1349599) and the Hong Kong ResearchGrants Council. U-series dating was supported bygrants of the Ministry of Education and Ministryof Science and Technology of Taiwan (Republic ofChina) and National Taiwan University. We thank theNational Museums of Kenya, the Kenyan NationalCouncil for Science and Technology, the KenyanMinistry of Mines, the National Environmental Management Authority of Kenya, Tata Chemicals, andMagadi County Council for permissions. DOSECCExploration Services (Salt Lake City, Utah, USA) provideddrilling support, and the National LacustrineCore Facility (Minneapolis, Minnesota, USA) assistedin drilling, core description, sampling, and core curation.Three anonymous reviewers are thanked for theirhelpful reviews. This is HSPDP publication #42
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Continental Scientific Drilling Facility tags
- HSPDP-MAG