Nonesuch Shale
| Nonesuch Shale | |
|---|---|
| Stratigraphic range: Proterozoic | |
Native copper replaces cross-bedded sedimentary rocks of the Nonesuch Shale, White Pine mine, Upper Peninsula of Michigan | |
| Type | Formation |
| Unit of | Oronto Group |
| Underlies | Freda Sandstone |
| Overlies | Copper Harbor Conglomerate |
| Location | |
| Region | Michigan |
| Country | United States |
The Nonesuch Shale is a Proterozoic geologic formation that outcrops in Michigan and Wisconsin, United States, but has been found by drill holes to extend in the subsurface as far southwest as Iowa.
The Nonesuch is a lacustrine sequence of shale, siltstone, and sandstone, 150 to 210 m thick, that conformably overlies the alluvial Copper Harbor Conglomerate and is conformably overlain by the fluvial Freda Sandstone. Together, the Copper Harbor, Nonesuch, and Freda make up the Oronto Group. The Nonesuch is Middle Proterozoic, with an estimated age of approximately 1.1 billion years. It was deposited in the Midcontinent Rift. The Nonesuch beds contain common organic carbon and pyrite.