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Lake Challa, Kenya

 

Professor Dirk Verschuren, University of Ghent

In late 2016, DOSECC will participate in the DeepCHALLA project in conjunction with the ICDP, the International Continental Scientific Drilling Program.  The project will  require our team to obtain core samples through open-water drilling on Lake Challa, a volcanic crater lake on the border of Tanzania and Kenya. The water body is fed by groundwater from Mount Kilimanjaro and is surrounded by a 100 metres high crater rim, requiring unique considerations for the design, systems engineering, and staff training necessary to obtain quality core samples.

Climate records obtained through sub-tropical cores are compared to those taken in polar regions to determine climate variations. Climate records previously available required the data additional samples from an equatorial region could provide in order to better map historical global climate patterns.  Lake Challa’s location provided an ideal location due to the convergence of both northern and southern hemisphere monsoon activity and the zone of convection between Atlantic and Indian Ocean moisture sources.

The goal of this project was to drill a quality core sample that would clearly show climate and ecosystem conditions over the past 250,000 years.  This span would encompass two full glacial-interglacial cycles and the entire known existence of modern humans in East Africa. The climate record’s length, in tandem with excellent sediment conditions, creates an unprecedented opportunity to better understand climate variability and record extremes and weather events.

Objectives:

  1. Reconstruct two glacial-interglacial cycles of tropical monsoon dynamics over the western Indian Ocean.
  2. Document long-term biodiversity patterns and ecological dynamics of a tropical savanna ecosystem in response to changes in atmospheric CO2, temperature, moisture balance, and fire.
  3. Reconstruct the long-term dynamics of a tropical freshwater ecosystem (nutrient budget, aquatic productivity) in response to climate-driven changes.
  4. Show exactly how often, when, and how much the East African landscape has changed throughout the entire existence of anatomically modern humans

Not only is this project designed to better understand and predict climate and ecosystem variations, it provides critical data in the study of why early human ancestors expanded from Africa into the Middle East and Eurasia ~100,000 years ago.

Read more about this scientific drilling project at ICDP .

November 2016 Lake Challa Scientific Drilling Project Update