|2006 Philadelphia Annual Meeting (22–25 October 2006)|
|Paper No. 28-21|
|Presentation Time: 8:00 AM-12:00 PM|
PRELIMINARY PALEOECOLOGICAL RESULTS FROM THE LAKE MALAWI SCIENTIFIC DRILLING PROJECT
COHEN, Andrew, Department of Geosciences, University of Arizona, Tucson, AZ 85721, firstname.lastname@example.org, PARK, Lisa, Department of Geology, University of Akron, Akron, OH 44325, MARTENS, Koen, Freshwater Biology, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, Brussels, 1000, Belgium, REINTHAL, Peter, Department of Ecology and Evolutionary Biology, Unviersity of Arizona, Tucson, AZ 85721, DETTMAN, David, Geosciences, Univ of Arizona, Tuscon, AZ 85721, STONE, Jeffery, Dept. of Geosciences, Univ of Nebraska, 214 Bessey Hall, Lincoln, NE 68588, BEUNING, Kristina, Department of Biology, University of Wisconsin, Eau Claire, WI 54702, SCHOLZ, Christopher, Department of Earth Science, Syracuse University, Syracuse, NY 13244-1070, JOHNSON, Thomas, Large Lakes Observatory and Department of Geological Sciences, University of Minnesota, Duluth, MN 55455, and KING, John, Graduate School of Oceanography, University of Rhode Island, Naragansett, RI 02882|
Scientific drilling at Lake Malawi, (East Africa Rift Valley) in 2005 yielded a remarkable set of long cores which provide a high resolution record of environmental and climate change covering the last ~1.5Ma. The cores are highly fossiliferous, with excellently preserved invertebrates (ostracodes, insects, mollusks and sponges), disarticulated fish fossils, diatoms and other fossil algae and terrestrial plant fossils and charcoal. Our initial investigations include a low resolution (~10ka sampling interval) analysis of the longest core collected (380m), and an intermediate resolution (~300 years) analysis of the last ~150ka from the same site.
The two drill sites are currently located in very deep water (Sites 1 and 2 in 592m and 361m respectively), well below the oxicline of this meromictic lake (~100m). Modern, surface sediment analyses demonstrate that there is minimal transport and preservation of littoral/profundal benthic fossils into deep-water environments. Thus, the abundant benthic or littoral fossils found at various horizons in the Lake Malawi cores provide an unambiguous record of extraordinary lake level fluctuations of at least 590m. Ostracode assemblages are generally of low diversity and dominated by taxa indicative of the saline lake conditions prevailing during the low-stand/arid intervals. Charcoal records show large scale variability in fire activity in the region. Ongoing studies of the isotopic (C and N) composition of fish bones is being used to understand variations in food webs and their relationship to lake level fluctuations.
2006 Philadelphia Annual Meeting (22–25 October 2006)
General Information for this Meeting
|Session No. 28--Booth# 150|
Core Analysis of Lake Sediments (Posters)
Pennsylvania Convention Center: Exhibit Hall C
8:00 AM-12:00 PM, Sunday, 22 October 2006
Geological Society of America Abstracts with Programs, Vol. 38, No. 7, p. 84
© Copyright 2006 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.