Tectonic Geomorphology above the Hellenic Subduction Zone:

Earthquake Hazards, Palaeolithic Hominins, and Stone Age Seafaring from the island of Crete, Greece

Karl Wegmann 

North Carolina State University

The island of Crete is in the forearc of the active Hellenic subduction zone, where syn-convergent extension results in large south-facing coastal escarpments with relief of > 4 km across the footwalls of active normal faults. Both erosional and constructional marine terraces are preserved on these uplifting footwalls. Near the Cretan town of Plakias, at the mouth of the Megas Patomas River in the Preveli Gorge, a flight of seven terraces (14 to 125 masl) preserves a record of rock uplift for the past 125 ka, at a rate of about 1 m/ka. C-14 dating of the lowest terrace, correlation to the global sea level curve, and estimates of soil profile maturity from the 125 m level are used to constrain terrace age. We have found lower Palaeolitic artifacts within terrace gravels of the 59 and 96 m terrace and as clasts in the Bt horizon of a terra rossa soil developed above 125 m (Mediterranean Soil Maturity Stage 6, ca. 110 ka). Thus, the artifacts definitively date to the Middle/Late Pleistocene if not earlier.

The migratory dispersals of early hominins from Africa to Eurasia is typically assumed to have occurred along land routes passing though southwest Asia and the Arabian Peninsula. The Mediterranean is usually viewed as a barrier to early hominine movements because pre-sapiens hominines were thought to lack the technical means or the cognitive skills to construct boats. The discovery of these early Palaeolithic artifacts challenges this view. Because Crete has been separated from the mainland throughout the Pleistocene, the presence of Pleistocene artifacts from southern Crete suggests that early hominines were capable of using sea craft to navigate open water, a finding that extends the history of seafaring in the Mediterranean back by more than 100 ky, an order of magnitude older than traditional dates for hominine dispersals to Crete and other Mediterranean islands, and as such has important implications for the dispersal of early humans.

Seminars