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National Geologic Map Database

Geologic Unit: Jordan

Usage:

Jordan Formation (IA,MN,WI)
Jordan Sandstone (IL*,IA*,MN*,MO*,WI*)
Jordan Sandstone Member of Trempealeau Formation (IA*,MI*,WI*)


Subunits:

(ascending) Norwalk (IA,WI*,MN*), Waukon (IA,WI), Van Oser (IA,WI*,MN*), Sunset Point (WI), and Coon Valley (IA,MN) Members.


Geologic age:

Cambrian, Late*
Ordovician, Early


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

Named from exposures in Sand Creek at Jordan, Scott Co., MN (Winchell, 1872).


AAPG geologic province:

Wisconsin arch*
Sioux uplift*
Iowa shelf*
Michigan basin*
Lincoln anticline*


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 ([ ]).