Proton micro-probe analysis of a speleothem from South Africa

Speleothems have been identified as being useful tools for reconstructing l ong continuous palaeoclimatic records. A stalagmite sample was taken from a Cold Air Cave (24 degrees S 29 degrees 11'E; 1500 m above sea level) in th e Makpansgat valley, South Africa, in order to investigate the possibility of using it to reconstruct climatic changes in southern Africa. The sample has been subjected to a series of analytical techniques that include radiom etric (Th-230/U-234) dating, stable isotope analysis (delta(18)O, delta(13) C) and grey scale intensity analysis. In addition it was decided to perform Particle Induced X-ray Emissions (PIXE) analysis using a proton micro-prob e. The advantage of this technique was that time variations in elemental co ncentrations could be obtained for each stratified layer ton an average 2.2 mm or similar to 10 yr) in the stalagmite and variations in elemental depo sition within these layers. Analysis for each discernible layer of the spel eothem, from the present to 3000 yr BP, was undertaken and is presented in this paper. (C) 1999 Published by Elsevier Science B.V. All rights reserved .