GSA Connects 2021 in Portland, Oregon

Paper No. 172-9
Presentation Time: 3:55 PM


ROBAKIEWICZ, Elena, University of Connecticut Geosciences, Beach Hall, Storrs, CT 06269-0001, OWEN, R. Bernhart, Dept. of Geography, Hong Kong Baptist University, Kowloon Tong, Hong Kong, DEINO, Alan, Berkeley Geochronology Center, 2455 Ridge Rd., Berkeley, CA 94709, TRAUTH, Martin H., University of Potsdam, Institute of Earth and Environmental Science, Potsdam, Germany and JUNGINGER, Annett, Senckenberg Centre for Human Evolution and Paleoenvironment (S-HEP), Tuebingen, 72070, Germany

The Early Midpleistocene Transition (EMPT) between 1,200–800 ka represents a major global climate transition from glacial cycles dominated by 41,000- to 100,000-year cycles. The mechanisms that caused this transition are not well understood and neither are how climates and environments altered during this period. Eastern Africa is no exception. Given the East African Rift System’s (EARS) active volcanism and tectonics, which add complexity to environmental systems and can destroy important proxy records (inhibiting studies of lacustrine dynamics), there is minimal understanding of how this transition impacted the region’s lake systems. At Paleolake Suguta in the Northern Kenya Rift, however, such volcanism capped lacustrine deposits with a flood basalt, preserving valuable proxies. This research presents a high-resolution reconstruction of hydrological changes during the EMPT at Paleolake Suguta in Kenya, which was likely hydrologically connected to Lake Turkana during this time. Paleo-lake dynamics are reconstructed from sediments of a 41 m outcrop KSI07 using diatom identifications, sedimentology, and XRF data as proxies. First results indicate that lake levels at Paleolake Suguta varied greatly across the EMPT, ranging from deep stratified lakes, to shallow, well-mixed lakes, to completely desiccated lake beds. Uncovering response times of the Suguta-Turkana basin to climate change will benefit not only EMPT research in a yet understudied region, but also of local fossil localities that can shed light on Mid-Pleistocene hominin evolution.