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Department of Geography


Testing the ‘megadrought’ hypothesis: the timing, cause and impacts of climate change in equatorial Africa

PI: Christine Lane
Collaborators: Dirk Verchuren, Melanie Leng, Phil Barker, Maarten Blaauw, Barbara Maher, Darren Mark.

Research into the timing, cause and impacts of tropical megadrought events recorded in the sediments of East African Lake Challa, a 90 m deep crater lake on the flank of Kilimanjaro. Lake Challa contains an exceptional sedimentary record, with the proven potential to reconstruct past hydroclimate at high chronological precision and with dating accuracy not previously achieved in the tropics. A 215 m long sediment core was collected in November 2016, as part of the wider DeepCHALLA International Continental Scientific Drilling Project project (PI: Verschuren), which aims to reconstruct the climate and ecosystem dynamics on the East African equator over the last two glacial – glacial-interglacial cycles (ca. 250,000 years).

Christine Lane’s team in Cambridge is investigating the tephrochronological record in the Lake Challa sediments. In combination with palaeomagnetic dating, radiocarbon and varve counting methods, tephra layers are being used to build an age model for the sediments. Tephrostratigraphic correlations will also allow this unique record of tropical hydroclimate to be precisely correlated and compared to other records of eastern African environmental change.

For updates on the progress of the DeepCHALLA project, you can follow us on Facebook, on Twitter (@ICDP_DeepChalla) and the ICDP website.

Image: Drilling platform of the DeepCHALLA project on Lake Challa (Kenya-Tanzania), with the double peak of Mount Kilimanjaro in the background. Photo credit: Dirk Verschuren.