- Usage in publication:
-
- Taum Sauk Rhyolite
- Modifications:
-
- Named
- Dominant lithology:
-
- Rhyolite
- Tuff
- AAPG geologic province:
-
- Midcontinent region
Summary:
Taum Sauk Rhyolite. Unit is part of sequence of Precambrian volcanic rocks associated with Taum Sauk caldera in western part of St. Francois Mountains, southeast Missouri (Midcontinent region). Notable exposures on Goggins, Hogan, Lee, Proffit, Taum Sauk, and Wildcat Mountains, and may be present in places to south and east of Taum Sauk Mountain region. Consists of red to dark-maroon ash-flow tuff containing up to 30 percent phenocrysts of alkali feldspar and quartz; flamme locally present. Thickness over 1000 m, exposure not complete. Overlies Royal Gorge Rhyolite (revised); underlies Proffit Mountain Formation (new). Age is Precambrian. Report includes geologic map. Unit named and described on stratigraphic column (table 1).
Russell Mountain Rhyolite replaces: Hogan Mountain Rhyolite (Goggins, Hogan, Lee, Proffit, Taum Sauk, and Wildcat Mountains) as mapped by Tolman and Robertson (1969, Missouri Geol. Survey Rpt. Inv., no. 44); tuff of Taum Sauk Mountains of Anderson (1970, Missouri Geol. Survey Rpt. Inv., no. 46); and Unit 810a of Berry and Bickford (1972, Bull. Volcanology, v. 36, p. 303-318).
Type section: in sec. 15, T. 33 N., R. 2 E., Johnson Shut-ins quadrangle, MO. Origin of name not stated by author, but probably named from Taum Sauk Mountain, Iron Co., MO.
Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Taum Sauk Rhyolite
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Midcontinent region
Summary:
/Taum Sauk Rhyolite, 11th formation from base (of 12) of /Taum Sauk Group (new) of /St. Francois Mountains Volcanic Supergroup (revised). Study area is St. Francois Mountains, southeast Missouri (Midcontinent region). Overlies Royal Gorge Rhyolite (revised) of Taum Sauk Group; underlies Johnson Shut-ins Rhyolite (revised) of Taum Sauk Group. Age is Precambrian Y. Nomenclature listed in table 1.
[Conflicts with nomenclature guidelines (ACSN, 1970; NACSN, 1983, 2005, 2021): name Taum Sauk used for both group and formation within it (Taum Sauk Rhyolite has priority); name St. Francois Mountains applied concurrently to two different units in same area; a [supergroup] name combines a geographic name with the term ["supergroup,"] and no lithic designation is included.]
Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).