In excavations conducted near Crete's southwestern coast during 2008 and 2009, Strasser's team unearthed hand axes at caves and rock shelters. Most of these sites were situated in an area called Preveli Gorge, where a river has gouged through many layers of rocky sediment.
At Preveli Gorge, Stone Age artifacts were excavated from four terraces along a rocky outcrop that overlooks the Mediterranean Sea. Tectonic activity has pushed older sediment above younger sediment on Crete, so 130,000-year-old artifacts emerged from the uppermost terrace. Other terraces received age estimates of 110,000 years, 80,000 years and 45,000 years.
These minimum age estimates relied on comparisons of artifact-bearing sediment to sediment from sea cores with known ages. Geologists are now assessing whether absolute dating techniques can be applied to Crete's Stone Age sites, Strasser says.
Intriguingly, he notes, hand axes found on Crete were made from local quartz but display a style typical of ancient African artifacts.