Holocene Lacustrine Environment in the Western Eritrea-evidence from Freshwater Shells

Abstract

This study focused on finding of freshwater molluscs in Holocene sediments outcropping in western Eritrea. Three species of gastropods were found in calcareous sediments at the bank of a tributary river named Shatera River, within the license of Bisha Mines, they are Melanoides tuberculate (O. F. Müller, 1774), Bulinus globosus (Morelet, 1866) and Indoplanorbis exustus (Deshayes, 1833). The 14C dating on the shells of I. exustus and B. globosus was also carried out. The age dating result showed (9326-9134 cal yr BP) and (9134-8999 cal yr BP) respectively, of which are in the mid-Holocene epoch (11,000–5000 yr BP). This epoch is best known for it was a time when the northern and eastern part of Africa experienced a warm and humid climate.
 Among the freshwater molluscs, the existence of Melanonids tuberculate makes it more significant, for its widespread occurrence in Quaternary deposits throughout Africa and Asia in both fresh and highly evaporated lakes. This is suggestive of the considerable development of the lacustrine environment in the western part of Eritrea, which at present has disappeared.