GEOCHRONOLOGY OF PHREATOPHYTIC MOUNDS ON THE ATMUR EL KIBIESH, EGYPT: WITH DESCRIPTIONS OF PLANTS COLLECTED DURING THE EXPEDITION TO THE EASTERN SAHARA, EGYPT, AND SUDAN (APPENDIX I)

In the hyperarid eastern Sahara, west of the Nile River in Egypt, areas with vegetated eolian mounds have attracted people and animals because of shallow groundwater that at times of high water tables may be reached by hand digging shallow wells. An eolian phreatophytic mound with a living arak bush (Silvadora persica L.) on top, one of three known from this region of SW Egypt, provided a stratigraphic record of its growth. The geochronology of the mounds aggradation and that of a nearby tarfa mound (Tamarix nilatica Bunge) was determined by radiocarbon dating plant macrofossils within the stratigraphic succession. Eolian aggradation of the mound postdates deflation that eroded playa sediments of the Neolithic pluvial that ended ca. 5000 BP and appears to be due to a resurgence of the shallow aquifer. Subsequent deflation of the mounds is apparently due to post-1500 BP aridity. Regional vegetation is described in the Appendix I.