New Evidence Suggests Ice-Age Mariners May Have Been Extracting Volcanic Rocks from Aegean Sea

A new technique which dates Obsidian, (a black or gray volcanic stone that is hard and sharp like glass) has shed new light on whether mariners were mining for the mineral-like stone in the Aegean sea much earlier than 13,000 years ago as previously thought.
Nicolaos Laskaris of the University of the Aegean in Greece, along with his colleagues, recently published a paper in the September issue of the Journal of Archaeological Science about evidence they claim suggests seafaring traders were in fact, traveling the Mediterranean waters before the end of the last ice age. These ice-age mariners, were extracting coveted volcanic rocks for pre-Bronze age tools, blades and weapons.
This discovery comes from obsidian artifacts found in the Franchthi cave, a very large cave, overlooking what is now a small inlet off the Aegean Sea in the southeastern Argolid region of Greece, near the modern town of Kiladha. Earlier excavations at the cave had discovered obsidian dated around 8,500 B.C. However, Laskaris and his colleagues now dispute this theory after turning to a method called obsidian hydration dating (OHD).
The method combined with a newer technique known as secondary ion mass spectrometry of surface saturation (SIMS-SS), determines how much water had penetrated the obsidian surfaces that were exposed to the air by prehistoric humans who were chipping the rocks to make tools and weapons. Previous geochemical work in the cave had already established the volcanic artifacts were from Milos, well-known over the centuries for having this valuable rock. However, Laskaris is now pretty certain that the obsidian was being mined and shipped to the mainland much earlier in a prehistoric Greece.