There is quite strong evidence that the peculiar, almost elemental, copper deposits of the Michigan Upper Peninsula were the primary source of copper for Bronze during the Bronze Age. Sunken boats have been found in the Mediterranean with these peculiar metals. Indians have stories of tall, light-skinned explorers/extractors who managed mining and distribution of this copper.
Of course, the time of the Bronze Age (3600-1200 BC) does not represent the earlier epoch which this article refers to. However, it is strong evidence of longstanding voyages between Europe and the New World.
While it’s possible copper crossed the Atlantic, more is known about the use and (overland, riverine) trade of copper in precolumbian America. In the Mediterranean, the copper of Cyprus shipped as “oxhide” ingots (easier to handle and carry) was mined and traded for a long, long time, and those ingots show up on wrecks and in the ruins of ancient cities.
Romans in Brazil During the Second or Third Century?
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