K. Holmgren et al., PALEOCLIMATIC SIGNIFICANCE OF THE STABLE ISOTOPIC COMPOSITION AND PETROLOGY OF A LATE PLEISTOCENE STALAGMITE FROM BOTSWANA, Quaternary research, 43(3), 1995, pp. 320-328
High-resolution delta(18)O and delta(13)C analyses of a stalagmite fro
m Lobatse II Cave reveal late Pleistocene environmental changes in Bot
swana. Large shifts in delta(18)O and delta(13)C are observed between
two main periods of deposition. The first period, between 51,000 and 4
3,000 yr B.P., was warm and humid and may have been associated with so
me C-3 vegetation. The second period, between 27,000 and 21,000 yr B.P
., had temperatures approximately 2 degrees C lower, and vegetation do
minated by drought-adapted C-4 plants. The intervening period, between
43,000 and 27,000 yr B.P., bounded by two major hiatuses in stalagmit
e growth, produced discontinuous speleothem formation, probably under
dry conditions. New Th-230/U-234 mass spectrometry age determinations
for the stalagmite generally agree with previously measured Th-230/U-2
34 ages. (C) 1995 University of Washington.