Hunter gatherers living beside Eagle Lake in Wisconsin manufactured 10cm long projectile points [otherwise known as arrow heads] out of pure copper. They were probably hammered into shape after heating the metal but this illustrates that copper was used by different people, fairly early in the Holocene. In this case, over 8000 years ago. See https://www.sciencemag.org/news/2021/03/ancient-native-americans-were-am… … see also https://doi.org/10.1126/science.abi6135 … a new study of the copper arrowheads and traces of prehistoric mining in the region, have concluded the so called Old Copper Culture emerged earlier than previously thought. It also mysteriously disappeared around 3000 years ago. So, it thrived between 8000 and 3000 years ago – but why was it replaced by a return to bone and stone tools? The answer may be bound up in the same events that led to the demise ofr the Bronze Age civilisations of the Old World, the end of LB event in the Near East, Aegean, Egypt etc. If catastrophism were to be factored in one might not be so surprised at the outcome. The author of the piece suggests climate change played a role. Overloading of the upper atmosphere by meteorite dust would do just that.
ItIt is not surprising copper was used early in this part of the world as large pure copper deposits can be found in the Great Lakes region. At some point the locals developed the idea of heating the ore in order to grind it or hammer it into the shapes desired. They left behind thousands of mine workings and countless copper artefacts such as arrow heads, knives, axes, fish hooks, and awls. The big mystery is why the locals abandoned the use of metal ores to make tools. It may indicate the locals migrated at the turn of the first millennium BC, moving south. Newcomers may not have been conversant with copper mining and tool manufacture. However, beads and trinkets continued to be made from copper, and awls.
The new findings derived from modern C14 methodology, the Bayesian version, have shifted the dates to somewhat older in time, as early as 9500 years ago we are told. It peaked between 7000 and 5000 years ago = 5000-3000BC [the mid Holocene Warm Period].