Bellefonte Formation

The Ordovician Bellefonte Formation (Obf) is a mapped bedrock unit in central Pennsylvania.

Description

The Bellefonte is defined as a medium-gray, brownish-weathering, medium-bedded dolomite and minor sandstone. The very fine grained Tea Creek Member lies above, and the crystalline Coffee Run Member lies below.[1]

Depositional Environment

Deposition of formations such as the Bellefonte Dolomite occurred in environments equivalent to the modern Bahama lagoons, east of Miami.[2]

Age

Relative age dating of the Bald Eagle places it in the Ordovician period. It rests atop the Axemann Formation (Oa),[1] or the Nittany Formation, for example between Tyrone and Water Street, Pennsylvania, where the Axemann is missing, and the Loysburg Formation of interbedded limestone and dolomite conformably overlies the Bellefonte Formation.[3]

Economic Uses

See also

References

  1. ^ a b "Explanation of Geologic Units". Pennsylvania Geological Survey. http://www.dcnr.state.pa.us/topogeo/map1/explanation.pdf. Retrieved 2008-01-26. 
  2. ^ "Structures of The Appalachian Foreland Fold-Thrust Belt: Fold-Thrust Geometries of the Juniata Culmination (State College and Environs), Central Appalachians of Pennsylvania". Pennsylvania State University Department of Geosciences. http://72.14.205.104/search?q=cache:Gahcnodzl0oJ:www.geosc.psu.edu/~engelder/geosc465/Trip.rtf+%22Bald+Eagle+Formation%22+NAME&hl=en&ct=clnk&cd=3&gl=us&client=firefox-a. Retrieved 2008-01-27. 
  3. ^ "Trenton Black River Carbonates: Stop 3". Trenton and Black River Carbonates in the Union Furnace Area of Blair and Huntingdon Counties, Pennsylvania. Pennsylvania Geological Survey. http://www.dcnr.state.pa.us/topogeo/tbr/stop3.aspx. Retrieved 2008-01-27.