The Topography of Libyan Sand Grains

The archaeological remains of Libya, prehistoric as well as Classical, have long served as guides to the age of the landscapes and deposits with which they are associated. To give a familiar example, the elevation of the ancient harbours of Apollonia and Lepcis Magna relative to present-day sea level is used in determining the extent of submergence or emergence since Antiquity. Other instances of archaeological dating may be found in the studies devoted to the Quaternary geology and geomorphology of Libya which were briefly reviewed in the Society's Fourth Annual Report (1972–3, pp.9–10). Hitherto, archaeological dating has been applied to substantial portions of the landscape in order to establish when they were formed, destroyed, deformed or displaced. It is now beginning to prove fruitful in investigating the history of individual sand grains, although still with the aim of evaluating gross environmental changes. The items whose age is here at issue are identified with the help of the Scanning Electron Microscope (SEM), whose application to the study of quartz grains is primarily associated with the name of D. H. Krinsley of the City University of New York. The SEM allows grains to be examined at a wide range of magnifications with all the advantages to be gained from a great depth of focus. Plates 1–4 illustrate the kind of detail revealed by the SEM on grains from deposits in Wadi Ganima, Tripolitania.