A high-resolution multi-proxy stalagmite record from Mechara, Southeastern Ethiopia: Paleohydrological implications for speleothem paleoclimate reconstruction
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An annually laminated stalagmite from Southeastern Ethiopia grew for 443 +/- 8yr starting at 5023yr BP (+/- 160yr) as determined by lamina-tuned U-Th dating. The speleothem shows three growth phases: (1) an initial phase where the stalagmite has a candlestick shape, deposited by relatively slow rate drip water; (2) a middle growth phase where laminae grow on the flanks, suggesting faster drip rates; and (3) a final growth phase where the speleothem becomes narrower owing to a decrease in drip water supply towards the end of deposition. Morphometry, annual growth rate, fluorescence index, and U-234/U-238 isotope ratio show marked differences between the growth phases, while delta C-13 and delta O-18 do not show significant variation, except within the third phase towards the top of the stalagmite, where they have higher values. The study indicates that the multiproxy approach is crucial as the different proxies respond to single climate forcing in different manners. Our results can be widely applied to speleothem studies distinguishing the relative importance of the various proxies in recording cave 'external' (climate, hydrology) and cave 'internal' (e.g. evaporation) processes. Copyright (c) 2006 John Wiley & Sons, Ltd.
|Number of pages||11|
|Journal||Journal of Quaternary Science|
|Publication status||Published - 1 Jan 2007|
- palaeohydrology, Ethiopia, palaeoclimate, Holocene, stalagmite