Type of Culminating Activity
Master of Arts in Anthropology
Christopher L. Hill, Ph.D.
Contemporaneous with the transition to biologically modern humans was the episodic change from wetter to drier environments in the Egyptian Sahara. At Bir Tarfawi, White Lake sediments represent a wet phase occurring prior to the last interglacial in the now hyperarid Egyptian Western Desert. One hypothesis for the development of Western Desert Pleistocene lakes was that the northward migration of the Intertropical Convergence Zone (ITCZ) provided a path for summer-constrained, Atlantic-sourced precipitation resulting in local precipitation. Oxygen and carbon stable isotope analysis of climate proxies such as the gastropod, Melanoides tuberculata, indicate precipitation and groundwater sources as well as the ephemeral or perennial character of the surface water. Unaltered diagenetically, Melanoides from a coquina in White Lake sediments had shell carbonate oxygen isotope values from -7.7‰ to 0.8‰. Along shell oxygen isotope values varied from 3‰ to 6‰ with no indication of highly depleted values indicative of Atlantic-sourced monsoon. Also, the shell oxygen isotope values were higher than previously published perennial lake sediment carbonates (-8.3‰ to -5.7‰). The enriched oxygen isotope values for White Lake remnant Melanoides suggest the coquina may have formed in shallow waters sensitive to evaporation and multiple precipitation sources, e.g. Indian Ocean, contradicting the hypothesis that the Atlantic monsoon was the sole contributor to the perennial White Lake.
Bradbury, Cynthia Anne, "Middle Paleolithic Hominin Lake Environments in Saharan North Africa" (2011). Boise State University Theses and Dissertations. 229.