Colchis LGM CHG Isolated Refugium and Refugia: Glaciers and permafrost: Dzudzuana example


«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]

In this case is to be taken into account situation, when Dzudzuana cave may be was out of reach for existing CHG population and not fact of absence of population — because place was covered with glacier and permafrost.

Dzudzuana cave was inhabited intermittently during several periods dated to 32 to 26 thousand years before the present (kyr B.P.), 23 to 19 kyr B.P., and 13 to 11 kyr B.P.

Dzudzuana cave (like Kotias Klde {***}), situated 560 meters above modern sea level and 12 meters above the current channel of the Nekressi River,  most probably was used by CHGs periodically/seasonally (not for permanent living) and especially during late spring – early summer (time when hunting was main source of food). [2] Other seasons CHGs can find enough food gathering chestnut and other plants.

During LGM during late spring (especially) and even early summer local glacier was of maximum size, so Dzudzuana cave and surroundings were not useful and out of main hunting territory. This resulted absence of evidence archaeological data.

journal.pone.0111271.g004

Satsurblia: New Insights of Human Response… Ron Pinhasi, at.al

W.refugia Dzudzuana

W.refugia 750.jpg

map dzudzuana 01

Dzudzuana, Caucasus nowadays macro landscape

*

map dzudzuana 03a

Caucasus. Colchis valley, Dzudzuana and line of permafrost during LGM (red line)

*

map dzudzuana 02.jpg

Dzudzuana valley LGM possible permafrost line and glacier

*

dzudzu3a

Simulated Dzudzuana cave like landscape during non-LGM and LGM periods in mid-summer. Glaciers and permafrost making surroundings unusable for CHG for hunting and gathering even during summer time.

*

Europe20000ya

European LGM refuges, c. 20,000 BP
  Solutrean and Epigravettian


{*} Satsurblia (საწურბლია) sample is from the right temporal bone of a hunter-gatherer found in Satsurblia cave in western Georgia. The bone was dated to 13,132–13,380 BP, during the late Upper Paleolithic.

{**} Dzudzuana (ძუძუანა) an Upper Palaeolithic cave site in the Caucasus foothills (Georgia)

{***} Kotias Klde (კოტიას კლდე/მღვიმე): The Kotias Klde sample is from the skeleton of a hunter-gatherer found in Kotias Klde cave in western Georgia. The skeleton was dated to 9529–9895 BP, during the Mesolithic.

[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] Охота на медведя в мезолите на южном кавказе. Бар-оз Г., Бельфер-коэн А., Мешвелиани. Т, Жакели Н, Мацкевич З, Бар-йозеф О.


May be important for understanding Z6046 appeared during LGM (formed 18400 ybp) and subclades development specific aspects

Opinion: «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.»
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4213019/

In this case is to be taken into account situation, when Dzudzuana cave (as all others) may be was out of reach for existing CHG population and not fact of absence of population — because place was covered with glacier and permafrost.

Dzudzuana cave (like Kotias Klde Y12379*), situated 560 meters above modern sea level and 12 meters above the current channel of the Nekressi River, most probably was used by CHGs periodically/seasonally[*] (not for permanent living) and especially during late spring – early summer (time when hunting was main source of food). Other seasons CHGs can find enough food gathering chestnut and other plants.
[*]http://lecturers.haifa.ac.il/en/hcc/gbaroz/Documents/BarOz%20et%20al.%202009%20JAAEur%20-%20RUSSIAN%20Version.pdf

During LGM late spring (especially) and even early summer local glacier was of maximum size, so Dzudzuana cave and surroundings were not useful and out of main hunting territory. This resulted absence of evidence archaeological data.

More research needed for Caucasus LGM glaciers and permafrost borders…

If presented idea is correct — then we have very small (1-3.000 persons and may be less) absolutely isolated during 10-13.000 years long period of LGM – group of people, whose DNA was affected with isolation and intensive (intensive) inbreeding till end of LGM and opening communications to outside world. In this case Caucasus and especially Western Georgia was not depopulated absolutely (hiatus) and then re-colonized but have had some local population with very specific DNA architecture and structure (bottleneck effect, etc.). If so, then both subclades of Z6046: Y12379 and Z6050 (formed 15500 ybp) appeared during bottleneck on very small territory and with extremely small population of South Caucasus, Western Georgia, Colchis

https://www.familytreedna.com/groups/j2-m172/activity-feed


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 SamegreloImeretiGuriaAdjaraAbkhazetiSvanetiRacha; modern Russia’s Sochi and Tuapse districts; and present-day Turkey’s RizeTrabzon and Artvin provinces.
https://en.wikipedia.org/wiki/Colchis


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.
https://en.wikipedia.org/wiki/Refugium_(population_biology)


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.
https://en.wikipedia.org/wiki/Last_Glacial_Maximum_refugia


 

Following the cold and dry phase of the Younger Dryas (c. 11,000–9500 BCE [13.000-11.500 ybp]), the beginning of the Holocene is seen in the Caucasus through an extension of a semi-arid, steppic environment. Most of the paleoenvironmental data seem to emphasise a certain degree of ecological homogeneity across the entire area during the Pre-Boreal and Boreal phases, except for a few glacial forest refugia such as Western Georgia.

The possible status of Western Georgia as a forest refugium may explain why it has provided the largest number of Mesolithic settlements in the South Caucasus. Most of the
known sites in the region are caves or rock shelters such as Apiancha, Kvachara cave, and Darkveti. While the majority of these sites have provided interesting stratigraphic sequences, none has produced a datable sample. In the Darkveti rock shelter, a Late Mesolithic layer (VI) is separated by 1 m of sterile sediments from an Early Neolithic layer (IV), overlaid by a Chalcolithic layer (III). Layer IV yielded microliths, as well as polished axes, graingrinders and faunal remains attributed to domestic species. Some issues with the dating, stratigraphy and attribution of domesticated status to this assemblage call for caution. Kotias Klde provides the best context to study early Holocene cultures in the region. Located in Imeretia, south of the Kvirila River, and close to Darkveti, Kotias Klde has produced two layers dated to 10,850–8240 BCE (layer B Mesolithic) and 7690–7300 BCE (layer A2 Early Neolithic).11 Kotias Klde’s Mesolithic industry is resolutely microlithic, and is characterised by a significant number of backed bladelets, with geometrics (scalene triangles) and end-scrapers. In two cases, the micro-burin technique is apparent. Furthermore, some bladelets and blades show traces of bipolar retouch. In layer A2, tools with hooked projections, characterised by continuously retouched lateral edges, were recorded

Source >

 


CHG: Caucasian Hunter Gatherers


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

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