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Expanded glaciers during a dry and cold last glacial maximum in equatorial East Africa

Meredith A. Kelly, James M. Russell, Margaret B. Baber, Jennifer A. Howley, Shannon E. Loomis, Susan Zimmerman, Bob Nakileza and Joshua Lukaye
Expanded glaciers during a dry and cold last glacial maximum in equatorial East Africa
Geology (Boulder) (June 2014) 42 (6): 519-522


Glaciers on the world's highest tropical mountains are among the most sensitive components of the cryosphere, yet the climatic controls that influence their fluctuations are not fully understood. Here we present the first (super 10) Be ages of glacial moraines in Africa and use these to assess the climatic conditions that influenced past tropical glacial extents. We applied (super 10) Be surface exposure dating to determine the ages of quartz-rich boulders atop moraines in the Rwenzori Mountains ( approximately 1 degrees N, 30 degrees E), located on the border of Uganda and the Democratic Republic of Congo. The (super 10) Be ages document expanded glaciers ca. 23.4 and 20.1 ka, indicating that glaciers in equatorial East Africa advanced during the global Last Glacial Maximum (ca. 26-19.5 ka). A comparison of these moraine ages with regional paleoclimate records indicates that Rwenzori glaciers expanded contemporaneously with dry and cold conditions. Recession from the moraines occurred after ca. 20.1 ka, similar in timing to a rise in air temperature documented in East African lake records. Our results suggest that, on millennial time scales, past fluctuations of Rwenzori glaciers were strongly influenced by air temperature.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 6
Title: Expanded glaciers during a dry and cold last glacial maximum in equatorial East Africa
Affiliation: Dartmouth College, Department of Earth Sciences, Hanover, NH, United States
Pages: 519-522
Published: 201406
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 29
Accession Number: 2014-060335
Categories: Quaternary geologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014184
Illustration Description: illus. incl. sketch map
N00°15'00" - N00°25'00", E29°49'60" - E30°00'00"
Secondary Affiliation: Brown University, USA, United StatesLawrence Livermore National Laboratory, USA, United StatesMakerere University, UGA, UgandaMinistry of Energy and Mineral Development/Petroleum Exploration and Production Department, UGA, Uganda
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201432
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