Semitic-IE loans and the Homeland.

It occurs to me that it just might be Semitic-speakers who became the
bearers of the art of copper and bronze. As to where they learned
about it, well, isn't there the remains of a GIGANTIC surface-deposit
of copper (mined out in deep antiquity) somewhere in Arabia?

Certainly, it is not at all difficult to imagine
Semitic-speaking masters of the magical art of metal setting
themselves up in the Caucasus, in the Kuro-Araxes culture (3500-2200)
on the South Face of the Caucasus. Certainly, the high culture of the
Caucasus came from the south. Just over the mountains, on the north
side of the Caucasus, in the Kuban valley, was the Maykop culture, of
approximately contemporaneous dates, and it is sometimes said to be
IE-speaking (and if it is, then it's PIE, and then, very close to the
homeland and perhaps even the Urheimat itself). Just north of Maykop
is Yamnaya (3600-2200) which is considered (at least partly) PIE in
the Kurgan Theory.

Just west of Maykop, just across the Kerch Strait, again of roughly
contemporaneous dates of 3700-2200 (and noted for its Maykop-derived
bronzes) we have the Kemi-Oba culture of the Crimea and parts north.
North of them and overlapping in space/time is the Lower Mikhaylovka
group, 3600-3000. This set is always mentioned when discussing the
Kurgan Theory. These are also part of the Kurgan tradition, but Maykop
seems not quite so affiliated with it.

Both Kuro-Araxes and Maykop know kurgan burials. Kuro-Araxes is said
to produce a remarkable quantity of wheeled vehicles along with a
'precocious' use of bronze.