In the Caucasus, at least four regional Mesolithic traditions can be distinguished, linking the late Upper Palaeolithic traditions of foragers with the arrival of a farming economy: the north-east Pontic area, extending to the steppes of the northern foreland; the south-western Imeretian variant; the Trialeti highlands, where communities had access to nearby obsidian sources; and the Dagestan Mesolithic. The Trialetian Mesolithic is probably the best known, representing a wide-spread industry that reached into the Trans-Caspian region, eastern Anatolia and the Iranian Plateau, although there is a lack of absolute dating (Sagona 2017).
The Imeretian culture developed on the slopes of the south-western Caucasus, with an origin in the Gravettian cultures of the region, which maintained contacts with the areas of Syria–Palestine and the Zagros Mountains. The introduction of micro-burin technique and a Natufian retouch, together with the geometric microliths, which appear most frequently in North Africa and the Near East, show an intensification of contacts with the population of Natufian culture of the Levant during the Holocene. At the same time, these new elements reach communities of the north-western Caucasus (Sagona 2017).
Kotias Klde, a karstik cave above the Kvirila River in western Georgia, and the Darkvety rock shelter, forms part of the Trialetian tradition. The lithic industry in Kotias Klde is relatively homogeneous in both types and technology, and comparable industries are found in distant territories, in particular at Ali Tepe in the Elbruz region of Iran, and Hallan Çemi. While a chronology is difficult to establish, it seems that the Trialetian elements appear first at Ali Tepe (ca. 10500–8870 BC), slightly later at Hallan Çemi (ca. 8600–7600 BC) (Sagona 2017).
There is a 1,000–year gap between the Epigravettian tradition of the Dzuzuana Cave and the Mesolithic findings of Kotias Klde, a seasonal camp by then, which suggests the arrival of new peoples, hunters of wild boar and brown bear during the late spring and early summer. In the southern Caucasus, the Chokh variant apparently continues the earliest ceramic tradition, but in Georgia there is a clear distinct period with Neolithic geometrics and the trapeze microlithic. Their diet was mostly composed of mammals, mainly deer (ca. 50%), but also brown bear (ca. 34%) probably mainly for fur and symbolic reasons. Unlike their Upper Palaeolithic predecessors, they did not hunt other ungulates, such as aurochs, steppe bisons, Caucasian tur, and wild horses (Sagona 2017).
The Chygai rock shelter, in the northern foothills of the western Caucasus, represents the lithic industry of the north-western Caucasus region. Their technological change is gradual, until the abrupt appearance of geometric microliths, especially trapezes, which mirrors the technological change of Crimea (see §II.3.1. North Pontic steppes). Remains of small mammals like ovicaprids and deer species are predominant in the early period, while larger animals such as bison and wild pig are hunted later on (Sagona 2017).
Different groups of Caucasus hunter-gatherers with strong differences in admixture emerging in the ancient DNA record support the existence of multiple small populations living in partial isolation, probably helped by the region’s orography. This is evidenced e.g. by the signs of recent consanguinity of the Mesolithic individual from Satsurblia; by the existence of a prehistoric genetic and cultural barrier around the Caucasus Mountains (Wang et al. 2019); and by the partial continuity of ancestral Y-chromosome and mtDNA haplogroups into the modern population of the southern Caucasus (Jones et al. 2015).
Close cultural contacts of the Imeretian culture linking the southern Caucasus and the Zagros Mountains probably reflect an ancient, Upper Palaeolithic network that allowed for the spread of ANE ancestry in the mainly AME-like population of the region, possibly through expanding Q1a2-M25 lineages from West Siberia. This is supported by its modern distribution in eastern Europe and central Asia, with a higher frequency in the Iranian Plateau under Q1a2a-L712 subclade (formed ca. 14300 BC, TMRCA ca. 11300 BC), apart from ancient samples in Aleutian Islanders, ancient northern Athabaskans, and in a sample from Cukotkan Ust’Belaya culture (Flegontov et al. 2016), as well as its estimated expansion ca. 10000 BC (Grugni et al. 2019). The resurgence of a fully ANE-like individual of Q1a2-M25 lineage in the Lola culture during the Bronze Age proves the persistence of small, isolated ANE-like populations in the Caucasus since the arrival of these migrants.