The Bronze Age appears to have originated around the Caucasus circa 3500 BCE, with the Maykop culture (3700—2000 BCE) and the approximately contemporaneous Kura-Araxes culture (3500—2200 BCE). Older Bronze objects have been found in Serbia dating from 4500 BCE, but the practice was discontinued until the Steppe people invaded the region c. 3000 BCE.
The Chinese Bronze Age started relatively early, c. 3100 BCE with the Majiayao culture, located around the modern provinces of Gansu and Qinghai, roughly between Mongolia and Tibet. It is interesting that the Bronze Age should have appeared in such a remote north-western region, along what would become the Silk Road, and in direct continuity of the Tarim basin.
Archaeology shows that a group of early horse riders from the Repin culture (3700-3300 BCE) in the Don-Volga region migrated to the Altai mountains, establishing the Afanasevo culture (c. 3600-2400 BCE). I have postulated that those Afanasevo people, who most probably belonged to Y-haplogroup R1a and/or R1b, moved south to the Tarim Basin. So far the oldest evidence of the presence of R1a in the Tarim basin comes from the testing of 4000 year-old Y-DNA by Li et al. (2010). All the samples tested belonged to R1a1a.
Whether R1a or R1b people moved into Xinjiang (north-west China) as early as the 4th millennium BCE remains to be determined. Notwithstanding, the Afanasevo culture in the Altai was a Copper then Bronze Age culture and spread over a very wide region north of the Altai and into modern Mongolia. I doubt that it is a coincidence that Majiayao culture, just on the other side of the Altai and Gobi desert, suddenly developed bronze working on its own without any influence of the nearby Afanasevo culture.
Afanasevo people were horse riders who had journeyed thousands of kilometres from the Volga region until Mongolia. Surely they must have come into contact with the Chinese at one point or another, whether it is them who travelled to China, or Chinese traders who travelled to the Altai. Either way the Chinese could have imported copper and bronze artefacts and learned how to make some themselves.
Let us keep in mind that bronze technology has not emerged independently anywhere in western Eurasia, and was not properly developed at all in Africa, Papua, Australia or the Americas. All the Middle Eastern, South Asian, Central Asian and European bronze ages have their source in the North Caucasus, which was itself an offshoot of the Balkano-Anatolian Copper Age.
It would be an unmatched historical coincidence if the Chinese managed to invent the bronze alloy completely on their own exactly a few centuries after steppe nomads brought bronze technology to Mongolia. I don't believe is that kind of coincidences.
There is even genetic evidence to support that a small number of Proto-Indo-Europeans (R1a and/or R1b) infiltrated the whole East Asian gene pool. Haplogroup R1a and R1b are found at high percentages in the Altai (40% to 90% of male lineages), at relatively high percentages in Xinjiang (up to 20% in some Uyghur populations), and in small but substantial percentages in Mongolia (up to 10%). R1a has also been found at trace frequencies among Han Chinese.
More interestingly, autosomal DNA also shows that most East Asians (Chinese, Koreans, Japanese) have a traces of Northeast European DNA. The K12 data of the Dodecad Project shows, for example, that the East European admixture is found in 0.9% of Japanese, 0.8% of Chinese, and 0.6% of Korean people from the project. This admixture has been found to correlate extremely reliably with haplogroup R1a, and is completely absent from the Sardinian population, which was completely bypassed by the Indo-European migrations.
Therefore I would like to propose that the Bronze Age in China was introduced by a small number of R1a individuals from the Afanasevo culture shortly before 3100 BCE.
The main difference with western Eurasia is that this wasn't a conquest. The Indo-European language and culture did not replace or even visibly influence that the various Neolithic Chinese cultures of the time. The only possible Indo-European contribution is the concept of a supreme sky deity, which appears in China during the Bronze Age under the name of Shangdi, a Chinese equivalent of Zeus, Jupiter, Odin and other regional variants of the Proto-Indo-European sky god.
The Chinese Bronze Age started relatively early, c. 3100 BCE with the Majiayao culture, located around the modern provinces of Gansu and Qinghai, roughly between Mongolia and Tibet. It is interesting that the Bronze Age should have appeared in such a remote north-western region, along what would become the Silk Road, and in direct continuity of the Tarim basin.
Archaeology shows that a group of early horse riders from the Repin culture (3700-3300 BCE) in the Don-Volga region migrated to the Altai mountains, establishing the Afanasevo culture (c. 3600-2400 BCE). I have postulated that those Afanasevo people, who most probably belonged to Y-haplogroup R1a and/or R1b, moved south to the Tarim Basin. So far the oldest evidence of the presence of R1a in the Tarim basin comes from the testing of 4000 year-old Y-DNA by Li et al. (2010). All the samples tested belonged to R1a1a.
Whether R1a or R1b people moved into Xinjiang (north-west China) as early as the 4th millennium BCE remains to be determined. Notwithstanding, the Afanasevo culture in the Altai was a Copper then Bronze Age culture and spread over a very wide region north of the Altai and into modern Mongolia. I doubt that it is a coincidence that Majiayao culture, just on the other side of the Altai and Gobi desert, suddenly developed bronze working on its own without any influence of the nearby Afanasevo culture.
Afanasevo people were horse riders who had journeyed thousands of kilometres from the Volga region until Mongolia. Surely they must have come into contact with the Chinese at one point or another, whether it is them who travelled to China, or Chinese traders who travelled to the Altai. Either way the Chinese could have imported copper and bronze artefacts and learned how to make some themselves.
Let us keep in mind that bronze technology has not emerged independently anywhere in western Eurasia, and was not properly developed at all in Africa, Papua, Australia or the Americas. All the Middle Eastern, South Asian, Central Asian and European bronze ages have their source in the North Caucasus, which was itself an offshoot of the Balkano-Anatolian Copper Age.
It would be an unmatched historical coincidence if the Chinese managed to invent the bronze alloy completely on their own exactly a few centuries after steppe nomads brought bronze technology to Mongolia. I don't believe is that kind of coincidences.
There is even genetic evidence to support that a small number of Proto-Indo-Europeans (R1a and/or R1b) infiltrated the whole East Asian gene pool. Haplogroup R1a and R1b are found at high percentages in the Altai (40% to 90% of male lineages), at relatively high percentages in Xinjiang (up to 20% in some Uyghur populations), and in small but substantial percentages in Mongolia (up to 10%). R1a has also been found at trace frequencies among Han Chinese.
More interestingly, autosomal DNA also shows that most East Asians (Chinese, Koreans, Japanese) have a traces of Northeast European DNA. The K12 data of the Dodecad Project shows, for example, that the East European admixture is found in 0.9% of Japanese, 0.8% of Chinese, and 0.6% of Korean people from the project. This admixture has been found to correlate extremely reliably with haplogroup R1a, and is completely absent from the Sardinian population, which was completely bypassed by the Indo-European migrations.
Therefore I would like to propose that the Bronze Age in China was introduced by a small number of R1a individuals from the Afanasevo culture shortly before 3100 BCE.
The main difference with western Eurasia is that this wasn't a conquest. The Indo-European language and culture did not replace or even visibly influence that the various Neolithic Chinese cultures of the time. The only possible Indo-European contribution is the concept of a supreme sky deity, which appears in China during the Bronze Age under the name of Shangdi, a Chinese equivalent of Zeus, Jupiter, Odin and other regional variants of the Proto-Indo-European sky god.