So the question I have is When (what range of time) should each GS come out of Preh Era? The current 20,000BC to 6,000BC?
I'm currently watching "stories from the stone age" (*)
(*)
https://www.youtube.com/watch?v=-7bqi70B3tE&list=PL9BB248CA3F85D500
It tells how a bunch of hunter-gatherers in the middle-east slowly developed a sedentary lifestyle and experimented with growing crops. However shortly after that the climate became much dryer due to a small ice age during the Younger Dryas era which started around 11,000 BC. As there was much less nature to hunter-gather from due to general lack of moisture, these people were forced to develop systematic farming around a handful of oases that were the only sources of water left in the area.
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From
https://en.wikipedia.org/wiki/Farm
"Farming originated independently in different parts of the world as hunter gatherer societies transitioned to food production rather than food capture. It may have started about 12,000 years ago [ i.e. 10K BC ] with the domestication of livestock in the Fertile Crescent in western Asia, soon to be followed by the cultivation of crops."
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So according to this we can place farming tech at about 10K-11K BC. As it comes directly after Sedentary Lifestyle which ends the prehistoric age, we should place sedentary lifestyle and the end of the prehistoric age somewhere between 11,000 BC - 12,000 BC.
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The wikipedia entry of Sedentism (which is the correct name for sedentary lifestyle) lists different dates in several parts of the world:
https://en.wikipedia.org/wiki/Sedentism
"Historical regions of sedentary settlements
A year-round sedentary site, with its larger population, generates a substantial demand on local naturally occurring resources, a demand that may have triggered the development of deliberate agriculture. In the Middle East the Natufian culture was the first to become sedentary at around 12000 BC. The Natufians were sedentary for more than 2000 years before they, at some sites, started to cultivate plants around 10000 BC. However, the first sedentary sites were pre-agricultural, and they appeared during the Upper Paleolithic in Moravia in Europe and on the East European Plain during the interval of c. 25000-17000 BC.[3]
The Jōmon culture in Japan, which was primarily a coastal culture, was sedentary from c. 12000 to 10000 BC until the cultivation of rice at some sites in northern Kyushu.[4][5] In northernmost Scandinavia, there are several early sedentary sites without evidence of agriculture or cattle breeding. They appeared from c. 5300-4500 BC and are all located optimally in the landscape for extraction of major ecosystem resources.[6] In Sweden, the Lillberget Stone Age village site (c. 3900 BC) represents such a site, as do the Nyelv site (c. 5300 BC) in Norway, and the lake Inari site (c. 4500 BC) in Finland.[7] In northern Sweden the earliest indication of agriculture occurs at previously sedentary sites, and one example is the Bjurselet site used during the period c. 2700-1700 BC, famous for its large caches of long distance traded flint axes from Denmark and southernmost Sweden (some 1300 km). The evidence of small-scale agriculture at that site can be seen from c. 2300 BC (burnt cereals of barley)."
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My judgement: Sedentary lifestyle tech, which ends the prehistory, should be researched at 12,000 BC. Unless you want to argue that the peoples of Moravia and the East European Plain rushed Sedentary lifestyle, followed by backfilling older techs instead of developing Farming, then Sedentary Lifestyle should be at 25,000-17,000 BC.