Galena Group
The Galena Group or Galena Limestone refers to a sedimentary sequence of Ordovician limestone that was deposited atop the Decorah Shale. It is part of the Ordovician stratigraphy of the Upper Midwestern United States. It was deposited in a calm marine environment, and is fossiliferous.
| Galena Group | |
|---|---|
| Stratigraphic range: Darriwilian-Sandbian | |
Unidentified Trochonema from the Galena Group | |
| Type | Group |
| Sub-units | Decorah Shale, Dunleith Formation, Wise Lake Formation, Dubuque Formation |
| Underlies | Maquoketa Group |
| Overlies | Platteville Limestone |
| Location | |
| Country | United States |
| Extent | Minnesota, Wisconsin and Illinois |
| Paleozoic Stratigraphy of the Upper Midwest, USA |
|---|
| Dates approximate |
| Maquoketa Group (446–440 Ma) |
| Galena Group (454–446 Ma) |
|
| Platteville Limestone (455–454 Ma) |
| Glenwood Shale (~455 Ma) |
| St. Peter Sandstone (~459–~455 Ma) |
| Knox Unconformity (~470-~459 Ma) |
| Knox Supergroup (~497-~470 Ma) |
|
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