RECONSTRUCTING QUATERNARY PLUVIAL EPISODES USING TRAVERTINES OF EGYPT'S WESTERN DESERT

Quaternary climate in North Africa was marked by multiple pluvial periods overprinting extreme aridity, but pluvial drivers, as well as their timing and geographic extent, are poorly constrained. We address these factors in the first comprehensive analysis of travertine from Egypt’s Western Desert, which represents a unique and under-utilized sedimentary record of paleoclimate and paleohydrology. We focus on correlating travertine deposition either to glacial cycles or to more specific orbital forcings, particularly precession, acting on the North African summer monsoon. An age-probability plot of published U-series ages shows no obvious correlation between travertine occurrence and glacial cycles (the dominant literature conclusion), so that forcings remain enigmatic. Following previous workers, we assume that large-scale travertine accumulations reflect pluvial episodes, via raised groundwater head supplying adequate water for travertine precipitation from CO₂-rich oasis springs. We collected ~60 additional geologically and volumetrically well-constrained samples in January, 2012, sampling deposit tops and bottoms to resolve inception and termination of pluvials as well as regional aggradation/incision patterns, and also banded feeder vein systems to establish finer-scale wet/dry fluctuations. Our goal is to contribute to an understanding of low-latitude climate and monsoon dynamics, as well as Western Desert hydrology, with implications for modern water management.