Bronze Age Town & Gulf Ports on the Copper Trail
Open-fire manufacturing of Copper Oxhides
continued from Page 6 … Jean Hunt, then President of the Louisiana Mounds Society, wrote in 1993 in Ancient American Magazine that “the Poverty Point archaeologist or curator talked about traces of large “spots” of copper on the surface, which he thought might have represented places where raw copper from the Michigan mines was placed while awaiting trans-shipment” (Ref.37). Metals would not be a normal surface finding. Daniel Wood also stated in Ancient American that “as many as 20 copper storage pits have been located at Poverty Point, measuring 15-20 feet in diameter (Ref.38). There was no visual evidence of these pits when I was there in 1996, but it appears they may show in the magnetic gradiometry (Fig.7). Wood describes a 20 x 50 foot Torch Lake (Keweenaw) pit that was found to contain 20 tons of carbonate of copper, that was dated c.1800 BC (also Ref.10), and other pits as far east as Sault Ste Marie, and others in southern Wisconsin.
The big unanswered question at this point is where the raw copper was heated on wood fires and poured into oxhide molds. No site has ever been identified. We know it was done with multiple pours, with enough moisture present to create voids in the oxhides, creating “blister copper” (see article on Michigan Copper in this book). Poverty Point is well forested land, and very humid, being on the Gulf Coast. The melting of the rough copper from the mines into standardized 60 pound one-Talent Oxhides would have required very hot fires. Multiple pourings into the clay moulds in the humidity of the Gulf Coast would have made the workers sweat profusely. Perhaps the sweat and humidity alone. or maybe wet “fresh” wood might have been enough to cause the gas voids that characterize the fragile “blister copper” oxhides. The carrying handles and flat shape of standardized oxhides would have been very helpful for shipping, carrying and selling the copper. With 99.7% of Poverty Point unexcavated, it may be this was the most important activity at Poverty Point, and clay or dirt molds should be watched for in future excavations.
Early in 2006. a magnetic gradiometry study done by Mike Hargrave and Burley Clay (Fig.7) shows large dark spots that were described as metal “hits,” or “something in the dirt that makes it magnetically different.” The State Site Archeologist, Dianna Greenlee says that by the end of May 2009 they have surveyed the entire plaza and the first two rings. She reports that the dark spots were tested with “pulled cores,” which showed dark midden material/hearths. They are especially interested in the circle patterns (see center of Fig.7). They have found many more of them, especially in the south Plaza, with larger circles in the east, smaller in the west. They are 50cm to 1 meter deep, in “good soil, so they are definitely prehistoric.” A Joint Field School excavation was scheduled for June 3 to July 2, 2009, with 3 staff, and 23 students from the University of Louisiana, and Mississippi State University. The students dug 1 x 2 meter holes over four of the circle patterns. Greenlee reported that the circles were found to be circles of filled postholes, where the posts were supported by PPO’s crammed next to them, producing the vertical stacks of PPO’s found by the students. In Europe, where stone is available, posts were similarly surrounded by “setting stones”, and these rings of stones reveal old post locations. Greenlee thought that more excavations will be helpful in determining whether the post circles were roofed, but thinks some were too large to roof. One radio carbon date has come back at 1440-1280 BC. No copper objects or hearths were noticed by the students in these four locations in June/July 2009.
Figure 10 shows the Claiborne and Cedarland Rings, contemporary with Poverty Point, which Gibson calls the “oddest Poverty Point community of all.” These mound-rings, in their tools …continued on Page 8