A Billion Years of History within the Grevena-Deskati Watershed

The river system of West Macedonia comprises the headwaters and western extent of the Aliakmon watershed.  This region has a unique and highly complex geologic history (Rassios, 2008; Rassios, 2011), many aspects of which can be inferred by examining conglomerate (river-cobble) formations in the region.  These formations contain all rock types found within the modern-day river basin, as well as some which are not found within today's basin.  River-deposited sediments and cobbles found along today’s Aliakmon and Venetikos River systems trace the courses of ancient river flows, and thus provide information about past climatic conditions and tectonic events.  The sediments making up conglomerate formations in the region are mature, containing cobbles which have been transported, consolidated, eroded and redeposited up to five times (Rassios and Grivas, 1998).  This recycling of cobbles leaves only the most durable rocks while softer rocks are destroyed via abrasion.  Prehistoric peoples availed themselves of this concentrated and convenient selection of high-quality stones for the purpose of fashioning tools and weapons.