Colchis LGM CHG Isolated Refugium and Refugia: Population: Hiatus vs Continuity


«The study of the UP Layer in Satsurblia has revealed evidence of human occupation during the pre-LGM period (Area B, Layers B/II and B/III), 25.5–24.4 ka cal. BP, an interval broadly contemporaneous with part of the occupation in Dzudzuana C (27–24 ka cal. BP). The chronology of Layer AII/a and A/IIb indicate the presence of a new post-LGM phase (Area A, Layers A/IIa and A/IIb: 17.9–16.2 ka cal. BP). The latter provides new evidence for human occupation in this region more than a millennium prior to what was previously known based on the radiocarbon-based chronology of Dzudzuana B (16.5–13.2 ka cal. BP…
The results of the campaigns in Satsurblia and Dzudzuana suggest that at present the most plausible scenario is one of a hiatus in the occupation of this region during the LGM (between 24.4–17.9 ka cal. BP). Future fieldwork will aim to assess earlier occupations and in particular to investigate whether the hiatus in occupation in Dzudzuana between Units D (34.5–32.2 ka cal. NP) and C (27−24 ka cal. BP) also occurs in Satsurblia, suggesting an additional regional (and potentially pan-regional) occupational hiatus.»[1]


Climatic suitability of Europe

Climatic suitability of Europe for human population over the LGM according to the simulation. (A) Changes in the percentage of potentially inhabited land area in Europe. (B) Percentage of time the area has potentially been inhabited between 30 and 13 ky ago. (C) Mean population density (people/100 km2 ) between 30 and 13 ky ago. [2]

Comparisons between simulated hunter-gatherer population size

Comparisons between simulated hunter-gatherer population size and density, the archaeological population proxy, and paleoclimatic simulations between 30 and 13 ky ago in Europe. (A) Simulated human population size in Europe. Error bars show the resampling-based confidence limits (95%). (B) Simulated mean density in the inhabited area of Europe. Error bars show the resampling-based confidence limits (95%). (C) Archaeological population size proxy based on the taphonomically corrected number of dates. (D) European mean of simulated potential evapotranspiration. (E) European mean of simulated mean temperature of the coldest month. (F) European mean of simulated water balance. D–F are based on the downscaling from the CLIMBER-2 climate model. [2]

Simulated human population range and density

Simulated human population range and density compared with the spatial distribution of archaeological sites during six time intervals from 30 to 13 ky ago. Archaeological sites are indicated with black dots and in each time slice they represent sites dated within 1,000-y bins. [2]

Stratigraphical data on lithic artefacts at Bondi Cave shows (Ages cal BP)
Layer IV — 24.530-23.530 and 23.500-22.980 — (24.5-22.3)
Layer V — 22.080-21.200 — (22-21.2)
LGM period: 24.5-21 [3, 4]

investigated sites in the Imereti region

Map of Georgia (B) and location of investigated sites in the Imereti region (A): 1-Dzudzuana Cave; 2-Satsurblia Cave; 3-Kotias Klde Cave; 4-Bondi Cave; 5-Samerckhle cave; 6-Khvedelidzeebis Cave; 7-Datvis Klde Cave. Triangles indicate studied caves with Upper Palaeolithic layers; circles indicate caves where only modern sediments were investigated. Kutaisi is the capital of Imereti. [3]

The Satsurblia karst cave is located in the Tskhaltubo region near the village Kumistavi at an altitude of 360 m a.s.l.
The karst cave Dzudzuana is located near the village Darkveti of the Chiatura municipality at an altitude of 560 m a.s.l.
The Bondi Cave is located north of the town of Chiatura at an altitude of 477 m asl.

So: Dzudzuana and Bondi Cave appeared too close to lower frontier of permanent snow during peak of LGM! 


Decrease of population in Europe as well in Caucasus during peak of LGM (24-18 ka cal. NP) objectively, comparatively decreases chances to find archeological material data about population, especially for Caucasus having much less total population then for Europe. So, evidences of absence of population according Satsurblia and Dzudzuana data can not be hardly extrapolated and maximized to the level of regularity for Caucasus. It is needed to check if continuity is common, regular for European archaeological sites inside continuate, uninterrupted population refugias. Actually, chances to find remains and material of population counting several thousand species after 20.000 years is harsh zero. Here is needed some ratio, criteria of population-number/discovery (as: 1 archaeological discovery for every 100.000 of population).

May be Satsurblia and especially Dzudzuana were located too high a.s.l. to be populated during peek of LGM?

Satsurblia and Dzudzuana were not populated afrer 13  ka cal. NP: New age of Hiatus?

[1] Satsurblia: New Insights of Human Response and Survival across the Last Glacial Maximum in the Southern Caucasus. R.Pinhasi, T.Meshveliani. at al.

[2] Human population dynamics in Europe over the Last Glacial Maximum. M.Tallavaaraa, M.Luoto, at al.

[3] Multiple origins of Bondi Cave and Ortvale Klde (NW Georgia) obsidians and
human mobility in Transcaucasia during the Middle and Upper Palaeolithic. F-X.Bourdonnec, S.Nomade, at al.

[4] Bondi Cave and the Middle-Upper Palaeolithic transition in western Georgia (south Caucasus). D.Pleurdeau, M.-H.Moncel, at al.

Colchis (/ˈkɒlkɪs/; Georgian: კოლხეთი Kolkheti; Greek Κολχίς Kolkhis) was an ancient kingdom and region on the coast of the Black Sea, centered in present-day western Georgia. It has been described in modern scholarship as “the earliest Georgian formation” which, along with the Kingdom of Iberia, would later contribute significantly to the development of the medieval Georgian statehood and the Georgian nation. Internationally, Colchis is perhaps best known for its role in Greek mythology, most notably as the destination of the Argonauts, as well as the home to Medea and the Golden fleece. It was also described as a land rich with gold, iron, timber and honey that would export its resources mostly to ancient Greece.

Colchis was populated by Colchians, an early Lazuri speaking tribe, ancestral to the contemporary Western Georgians, namely Svans and Mingrelians, as well as the related Lazs. Its geography is mostly assigned to what is now the western part of Georgia and encompasses the present-day Georgian provinces of Samegrelo, Imereti, Guria, Adjara, Abkhazeti, Svaneti, Racha; modern Russia’s Sochi and Tuapse districts; and present-day Turkey’s Rize, Trabzon and Artvin provinces.

In biology, a refugium (plural: refugia) is a location which supports an isolated or relict population of a once more widespread species. This isolation (allopatry) can be due to climatic changes, geography, or human activities such as deforestation and overhunting.

In anthropology, refugia often refers specifically to Last Glacial Maximum refugia, where some ancestral human populations may have been forced back to glacial refugia, similar small isolated pockets in the face of the continental ice sheets during the last glacial period. Going from west to east, suggested examples include the Franco-Cantabrian region (in northern Iberia), the Italian and Balkan peninsulas, the Ukrainian LGM refuge, and the Bering Land Bridge. Archaeological and genetic data suggest that the source populations of Paleolithic humans survived the glacial maxima (incl. the Last Glacial Maximum) in sparsely wooded areas and dispersed through areas of high primary productivity while avoiding dense forest cover.

Last Glacial Maximum refugia were places where humans survived during the last glacial period in the northern hemisphere, around 25,000 to 20,000 years ago.

CHG: Caucasian Hunter Gatherers

See also: Colchis LGM CHG Isolated Refugium and Refugia: Nutrition: Chestnut


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