Scientists find fossil proof of Egypt's ancient climate

'At a snail's pace'

By Tony Fitzpatrick

Feb. 2, 2005 — Earth and planetary scientists at Washington University in St. Louis are studying snail fossils to understand the climate of northern Africa 130,000 years ago.

While that might sound a bit like relying on wooly bear caterpillars to predict the severity of winter, the snails actually reveal clues about the climate and environment of western Egypt, lo those many years ago. They also could shed light on the possible role weather and climate played in the dispersal of humans "out of Africa" and into Europe and Asia. Periods of substantially increased rainfall compared to the present are known to have occurred in the Sahara throughout the last million years, but their duration, intensity, and frequency remain somewhat unconstrained.
Earth and Planetary Sciences graduate student Johanna Kieniewicz (left) holds 130,000 year-old snail fossils from an Egyptian lake while Jennifer R. Smith, Ph.D., assistant professor of earth and planetary sciences in Arts & Sciences, examines leaf impression in tufa, a spring carbonate rock found at the same site. The researchers are trying to infer the Egyptian climate from the fossil evidence.

Jennifer R. Smith, Ph.D., Washington University assistant professor of earth and planetary sciences in Arts & Sciences, and her doctoral student Johanna M. Kieniewicz, are using stable isotope and minor element analyses of the freshwater gastropod Melanoides tuberculata and carbonate silts from a small lake (now dry) in the Kharga Oasis of western Egypt to reconstruct climatic conditions during the lifetime of the lake. Their analyses support a surprising picture of arid Egypt: 130,000 years ago, what everyone considers an eternal desert was actually a thriving savannah, complete with humans, rhinos, giraffes and other wild life.

During the later periods of the Old Kingdom there are a series of drought and famine documented in Egyptian texts.