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.[1]

Galena Group
Stratigraphic range: Ordovician
TypeGroup
Sub-unitsPlatteville Limestone
UnderliesDubuque Formation
OverliesDecorah Shale
Location
CountryUnited States
ExtentMinnesota
Paleozoic Stratigraphy of the Upper Midwest, USA
Dates are approximate, and deposition occurred at slightly different times in different areas
Ordovician
Platteville Limestone / Group (455–454 Ma)
Ancell Group (454–455 Ma)
Glenwood Shale (~455 Ma)
St. Peter Sandstone (~459–~455 Ma)
--- Major Erosional Unconformity ---

Cambrian

Potsdam Supergroup/Potsdam Sandstone Megagroup
Munising Group
Davis Formation
Franconia Formation
Ironton Sandstone
Galesville Sandstone
Eau Claire Formation
Mount Simon Sandstone

References

  1. Mossler, J. and Benson, S., 1995, 1999, 2006, Fossil Collecting in the Twin Cities Area. Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.