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Old Copper Complex mining pollution detected in Great Lakes lake cores dating to 4500-3400 BCE

Excavation
The Roundtable Chronicles - Ep. 13
Source: The Roundtable Chronicles - Ep. 13 by Institute for Natural Philosophy

Site mentioned

📍 Lake Superior

Lake Superior sediment cores show lead pollution spikes from copper mining around 6000 years ago! ⛏️ The float copper mined in the Great Lakes region was exceptionally pure native copper. Researchers found that 90% of estimated extracted copper remains unaccounted for in the archaeological record!

Key facts claimed:

- Lake sediment cores from Lake Superior region show lead pollution spikes indicating copper mining activity

- Mining pollution evidence suggests copper extraction occurred around 6000 years ago during the Archaic period

- Carbon-14 dating of preserved organics inside copper artifacts shows a wide range spanning thousands of years

- Lead and other trace elements were released during annealing and heating processes

- Surface mining pits around Lake Superior rarely exceeded 10-20 meters in depth

Key facts

  • Lake sediment cores from Lake Superior and Isle Royale show lead pollution spikes indicating copper mining activity
  • Mining pollution evidence suggests copper extraction occurred between 4500 BCE and 3400 BCE
  • Carbon-14 dating of preserved organics inside copper artifacts shows a wide range spanning thousands of years
  • Lead and other trace elements including mercury and osmium were released during annealing and heating processes
  • Surface mining pits around Lake Superior rarely exceeded 10-20 meters in depth
  • Float copper from glacial deposits was nearly pure (99.9%) copper, the highest purity naturally occurring copper on Earth
  • Estimated copper extraction ranges from thousands to millions of pounds, but only 5,000 tons maximum found in archaeological record
  • The discrepancy between estimated extraction and recovered artifacts suggests 90% of mined copper is unaccounted for in North American archaeological record

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Sources

Lake Sediments Record Prehistoric Lead Pollution Related to Early ...researchgate.net
Nearly simultaneous lead enrichments occurred at Lake Manganese and Copper Falls Lake ~8000 and 7000 yr BP, indicating that copper extraction occurred ...
Native Americans Conducted Large-Scale Copper Mining 6000 ...scientificamerican.com
Analyzing lake sediments, the researchers found evidence of a peak in lead pollution around 6,000 years ago during the Archaic period. This ...
Native Americans Were Mining Copper 6,000 Years Agoanthropology.net
Native Americans Were Mining Copper 6,000 Years Ago. Near Lake Superior, prehistoric contamination shows massive copper mining. Feb 07, 2023. ∙ ...
Ancient mining pollution in early to middle Holocene lake sediments ...ui.adsabs.harvard.edu
Elevated concentrations of lead in sediments dating to ∼6000 years ago at both lakes provide evidence of atmospheric transport of pollution associated with ...
Lake sediments record prehistoric lead pollution related to ... - PubMedpubmed.ncbi.nlm.nih.gov
We analyzed the concentration of lead, titanium, magnesium, iron, and organic matter in sediment cores recovered from three lakes located near mine pits.
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