A new diatom record from Lake Victoria's Pilkington Bay, subsampled at 21- to 25-year intervals and supported by 20 AMS dates, reveals a ∼10,000 calendar year environmental history that is supported by published diatom and pollen data from two nearby sites. With their chronologies adjusted here to account for newly documented ancient carbon effects in the lake, these three records provide a coherent, finely resolved reconstruction of Holocene climate change in equatorial East Africa. After an insolation-induced rainfall maximum ca. 8800-8300 cal yr B.P., precipitation became more seasonal and decreased abruptly ca. 8200 and 5700 yr B.P. in apparent association with northern deglaciation events. Century-scale rainfall increases occurred ca. 8500, 7000, 5800, and 4000 yr B.P. Conditions after 2700 yr B.P. were generally similar to those of today, but major droughts occurred ca. 1200-600 yr B.P. during Europe's Medieval Warm Period.
Bibliographical noteFunding Information:
We thank H. Doose-Rolinski, F. Gasse, D. Livingstone, T. Partridge, J. Richardson, M. Talbot, P. Tyson, D. Verschuren, and U. von Raad for valuable discussions and the International Center for Research in Agroforestry, the National Science Foundation (ATM-9808972), and Paul Smith’s College for financial support. Undergraduate students Dustin Grzesik, Scott Hadam, Carlene Heimiller, and Kristen Przywara assisted in the collection and analysis of new cores collected from Lake Victoria in June 2000 that supported the chronology of core 64-2.
Copyright 2017 Elsevier B.V., All rights reserved.
- Lake Victoria
Continental Scientific Drilling Facility tags