U/Th isotopic study of speleothems from the Wadi Sannur Cavern, Eastern Desert of Egypt
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The Wadi Sannur Cavern was discovered in 1991 beneath an “Egyptian alabaster” (travertine) quarry, active since pharaonic times. It is the only extensively speleothem-decorated cavern that has been described in Egypt. Nine small stalagmites, 5–10 cm in diameter, were sectioned and sampled according to coloration bands a few cm thick. Of 32 individual samples several exhibited230Th/234U activity ratios greater than unity, indicative of open-system leaching of uranium, and several others had anomalous234U/238U activity ratios. The modal apparent age of the 17 “dateable” samples is close to 200,000 years, but because of leaching indications must be considered only a maximum age for the time of deposition of secondary carbonates in the cave. Both the initial formation of speleothems and subsequent leaching are consistent with what is known about pluvial climates in the Eastern Desert of Egypt.
KeywordsUranium Egypt Thorium 234U Activity Ratio
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- AKAAD, M.K. and NAGGAR, M.H., 1963, Geology of the Wadi Sannur alabaster and the general geological history of the Egyptian alabaster deposits:Bulletin de L’Institute du Desert d’Egypte, v. XIII, No. 2, p 36–63.Google Scholar
- HARRELL, J.A., BROWN, V.M., and MASOUD, M.S., 1996, Survey of ancient Egyptian quarries:Egyptian Geological Survey, Paper No. 92.Google Scholar
- IVANOVICH, M. and MURRAY, A., 1992, Spectroscopic Methods, Chapter 5.In Ivanovich, M. and Harmon, R.S., eds., Uranium Series Disequilibrium, 2nd Ed. Oxford University Press, p. 127–173.Google Scholar
- KLEMM, R. and KLEMM, D.D., 1933, Stein and steinbruche im Alten Agypten, Springer-Verlag, Berlin, p. 200–205.Google Scholar
- LALLY, A.E., 1992, Chemical Procedures, Chapter 4,in Ivanovich, M. and Harmon, R.S., eds., Uranium Series Disequilibrium, 2nd Ed. Oxford University Press, p. 95–126.Google Scholar
- PHILIP, G., AREL, M.M., DARWISH, M., and EWAIS, S., 1991, Paleoerosion surfaces and karst manifestations including “Egyptian Alabaster” in Gabal Homret Schaibun — Gabal Sannur area, East of the Nile Valley, Egypt:Egypt Journal of Geology, v. 34, p. 41–73.Google Scholar
- SAID, RUSHDIE, 1990, Quaternary. Chapter 25,in Said, Rushdie, ed., Geology of Egypt, Pergamon, Rotterdam/Brookfield, p. 487–510.Google Scholar
- SAID, RUSHDIE, 1993, The River Nile: Geology, Hydrology, and Utilization, Chap. 6, Pergamon, p. 32–56.Google Scholar
- SCHWARCZ, H.P., 1986, Geochronology and isotope geochemistry of speleothems, Chapter 7.In Fritz, P. and Fontes, J. Ch., eds., Handbook of Environmental Isotope Geochemistry, v. 2, Elsevier, Amsterdam, p. 271–303.Google Scholar
- SULTAN, M., STURCHIO, N., HASSAN, F.A., HAMDAN, M.A.R., MAHMOOD, A.M., ZEINHOM, E.A., and STEIN, T., 1997, Precipitation source inferred from stable isotopic compositions of Pleistocene groundwater and carbonate deposits in the Western Desert of Egypt:Quaternary Research, v. 48, p. 29–37.CrossRefGoogle Scholar