(USNewsMag.com) – A recent study has revealed evidence that Native Americans were mining copper 6,000 years ago.
Researchers found deposits of lead in sediment that dates back approximately 6,000 years in two separate lakes in Isle Royale National Park. The area, located in Michigan near Lake Superior, exhibits signs of pollution caused by mining. The fact that neither of the small lakes have mines in their catchments, or the natural drainage area from which the lake’s water originates, indicates the lead found in the sediment was transported atmospherically from mining emissions.
While the ancient mines in the region were first surveyed in the middle 19th century, the question of when exactly the Old Copper Complex was being actively mined has remained unanswered. The oldest artifacts dated through radiocarbon and organic materials date back over 8500 years.
By using sediment to date the extensive mining operations, the paleolimnological researchers were able to narrow down the window of the exact timing of the pre-contact mining. The analysis confirms prior archaeological data collected through carbon dating artifacts discovered in the vicinity.
Although the specific location of the mines from that era is still not clear, the data does indicate the area and scale of the ancient natives’ mining efforts, which must have been large enough to impact the environment in the region.
Paleolimnology is the study of past environments through the analysis of inland freshwater bodies and geological records. It attempts to reconstruct ancient environments based on the sediment found therein. By studying the sediment, scientists can draw conclusions about past ecosystems and climate.
The Old Copper Complex is an ancient North American culture archeologists have identified due to the copper tools, weapons, and ornaments discovered in the region. While some people that study the artifacts see evidence of smelting, other experts believe the metal could have been worked without extreme heat.
Archaeologically significant sites have been found in Michigan, Wisconsin, Ontario, and Manitoba. Copper artifacts have been found as far south as Mississippi.
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