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National Geologic Map Database

Geologic Unit: Gasconade

Usage:

Gasconade Dolomite (AR*,IL*,MO*)
Gasconade Formation (MO*)
Gasconade Dolomite of Arbuckle Group (subsurface of OK*,KS*)


Subunits:

Gunter Member (AR) or Gunter Sandstone Member (MO*,IL*,KS,OK).


Geologic age:

Early Ordovician (Canadian; Ibexian; Tremadocian; Skullrockian)*


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

Named from exposures on Gasconade River in Laclede, Pulaski, and Phelps Cos., central MO (Nason, 1892).
Reference sections (Thompson, 1991):
(1) exposures in southwest-facing bluff of Gasconade River valley, in SW/4 NW/4 NW/4 sec. 31, T. 37 N., R. 10 W., Dixon 7.5-min quadrangle, Pulaski Co., south-central MO; and
(2) roadcuts on U.S. Interstate Highway I-44 east of bridge over Roubidoux Creek, in NW/4 NW/4 SE/4 and NE/4 NE/4 SE/4 sec. 25, T. 36 N., R. 12 W., and in NW/4 NW/4 SW/4 sec. 30, T. 36 N., R. 11 W., Pulaski Co., MO.


AAPG geologic province:

Arkoma basin*
Chautauqua platform*
Cherokee basin*
Forest City basin*
Illinois basin*
Nemaha anticline*
Ozark uplift*
Sedgwick basin*
Upper Mississippi embayment*


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 ([ ]).