The Late Palaeolithic site of Ouriakos is located on the south-eastern coast of the island of Limnos in the northern Aegean. It was discovered in 2006 during the construction of a car park close to the beach which removed part of a sand dune (Figure 1, no. 1). The site is partly located on a Pleistocene calcarenite marine terrace, some 10m above present sea level, delimited by two seasonal streams (Figure 2). A profile along the right bank of the southern stream shows a buried dark clayey palaeosoil that developed above the calcarenite (Figure 3), containing chipped stone artefacts at its top, and which was sealed by a sand dune.
Surface collections made in 2008–2010 on the exposed archaeological surface (Figure 4), and the excavations that followed in 2009–2012, revealed that the site extends for some 1500m². The excavations were initially conducted on the area affected by the car park construction. Here the chipped stone assemblage was contained in a sandy layer, some 10–20cm thick, lying on the calcarenite terrace (Figure 5). The lower part of this deposit yielded a few unidentifiable bone fragments, a burnt sample of which was AMS-dated to 10 390±45 uncal BP/10 564–10 124 cal BC at 2σ (GrA-53229), suggesting that the site was settled during an advanced period of the Younger Dryas cold oscillation (c. 11 000–10 000 uncal BP; Lowe et al. 2001: tab. 3). In 2012, a test trench opened in an undisturbed area of the terrace, close to the edge of the southern stream bank, led to the discovery of an intact layer buried by a Holocene sand dune, at the top of the above-mentioned palaeosoil, from which in situ chipped stone artefacts were recovered (Figure 6).
The chipped stone assemblage from Ouriakos is manufactured mostly from limnic/hydroquartzite-calcedony-opal and varicoloured jasper pebbles. Systematic surveys have shown that the closest sources of these raw materials are located in the lower Kavouli valley (Figure 7), some 7km north-west of the site (Figure 1, no. 2), where conglomerates containing jasper pebbles outcrop from the river terraces; a rich deposit with limnic/hydroquartzite-calcedony-opal of various colours outcrops from the volcanic formations along the south-eastern slope of Kalogiros, in the upper part of the same valley (Figure 7).
A sample of some 8000 chipped stone artefacts has been analysed in two study seasons. Although both raw materials were utilised, it was observed that jasper artefacts are better preserved, whilst those manufactured from hydrothermal rocks are strongly weathered and patinated due to post-depositional processes in a salty environment that affects silica preservation (Sheppard & Pavlish 1992). Many lithic artefacts and bone fragments show contact with fire, despite the fact that no in situ fireplace has yet been found.
The large numbers of cores, debitage and waste flakes, crested blades, and by-products derived from core preparation and successive production stages suggest that the tools were produced on site. Apart from cores (Figure 8, nos. 20–26), the most characteristic implements are microlithic lunates (Figure 8, nos. 12–18) and end-scrapers (Figure 8, nos. 2–9). Other tools consist of a few oblique truncations, backed bladelets (Figure 8, nos. 10–11), burins (Figure 8, no. 1) and notched bladelets (Figure 8, no. 19). The Ouriakos lunates are distinctive tools of standardised dimensions. They are obtained using abrupt, bipolar retouch (Figure 9 top) without microburin technology, from microbladelets of scalene triangular cross-section detached by indirect percussion from small cores with one or more prepared platforms. The end-scrapers are represented by atypical long and short specimens of different size and thickness (Figure 9 bottom), obtained from varying types of blanks. The Ouriakos industry can be compared with material from layers Ia1–Ia2 of Öküzini Cave, north of Antalya (south-west Anatolia). These layers yielded lithic assemblages with bipolar lunates, and a great variety of end-scrapers (Kartal 2002), radiocarbon-dated using charcoal to the Younger Dryas (OxA-5