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National Geologic Map Database

Geologic Unit: Dubuque

Usage:

Dubuque Formation of Galena Group (IL*,IA*,MN*,WI*)
Dubuque Member of Galena Dolomite of Sinnipee Group (WI)
Dubuque Shale Member of Galena Dolomite (IL*,IA*,WI*)


Subunits:

FORMATION STATUS (alphabetical) --all in IL,IA,MN; all informal: Frankville beds, Littleport beds, Luana beds.


Geologic age:

Late Ordovician (Cincinnatian)*


Type section, locality, area and/or origin of name:

Named from Dubuque, Dubuque Co., eastern IA (Sardeson, 1907).
Principal reference locality (loc. 51): abandoned quarry [now Faber Clark Field, Loras College, Dubuque, IA], on north side of Loras Blvd. at Cox Street intersection, in SW/4 sec. 24, T. 89 N., R. 3 E., [approx. Lat. 42 deg. 30 min. 18 sec. N., Long. 90 deg. 40 min. 42 sec. W., Dubuque North 7.5-min quadrangle], Dubuque Co., eastern IA (Levorson and others, 1979).


AAPG geologic province:

Iowa shelf*
Wisconsin arch*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).