Pure Michigan copper contains unexpected mercury. The Superior Rift formed 3 billion years ago A wall of nearly pure copper exists in Lake Superior (40-80 feet tall, 18 ft thick) Between 100 million pounds and 120 million tons of copper were extracted
A wall of pure native copper 40-80 ft tall runs through Lake Superior's Midcontinent Rift (1.1 billion years old). The copper assays at 99.9% purity with traces of mercury - accessible from surface around 6000 BC, with mining evidence dating to around 4500 BC. The Keweenaw Peninsula hosted massive native copper deposits, with millions of pounds extracted by ancient peoples before European contact. 🏔️🪙
Key Facts
- The Superior Rift formed 3 billion years ago
- A wall of nearly pure copper exists in Lake Superior (40-80 feet tall, 18 ft thick)
- Between 100 million pounds and 120 million tons of copper were extracted
- The copper assays at 99.9% purity - normally requires electrolysis
- Mercury is present in the raw nuggets, surprising testing facilities in Sweden
- Mercury escapes when copper is heated above 500 degrees Celsius
- This copper was accessible from the surface around 4000 BC
- Mining likely began around 2500 BC
- Glaciers moved copper pieces as far south as the size of a trailer
Related site: Pyramide von 1810 (Mire), hist. Nullmeridian von Mannheim (Kurpfalz) — view location, images, and history on the Ancient Nerds map.
Source: Ep. 6 - The Shaman and the Philosopher - Rick Osmon by Institute for Natural Philosophy