- Usage in publication:
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- Iron Mountain conglomerate
- Modifications:
-
- Original reference
- Dominant lithology:
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- Conglomerate
- AAPG geologic province:
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- Ozark uplift
Summary:
Pg. 331, 354. Iron Mountain conglomerate. Conglomerate underlying La Motte [Lamotte] sandstone and forming basal part of Ozark series in southeastern Missouri. Possibly of Cambrian age.
[Named from Iron Mountain, St. Francis Co., southeastern MO.]
Source: US geologic names lexicon (USGS Bull. 896, p. 1024).
- Usage in publication:
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- Iron Mountain conglomerate*
- Modifications:
-
- Overview
- AAPG geologic province:
-
- Ozark uplift
Summary:
Described at Iron Mountain, St. Francois Co, MO, Ozark uplift, as consisting of boulders and pebbles of Archean rocks occupying depressions in old land surface. Found in subsurface at Doe Run. Irregular distribution; often absent. Thickness 50-100 ft. Overlies Archean crystallines. Underlies La Motte sandstone. Age is early Silurian.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Iron Mountain conglomerate
- Modifications:
-
- Not used
Summary:
In southeastern Missouri (Ozark uplift), the name Iron Mountain conglomerate is discontinued. Local conglomerate beds, when they occur, may be regarded as local basal facies of the La Motte [Lamotte] sandstone. Age not stated [a Silurian age is suggested, see below].
[According to GNU records (USGS DDS-6; Denver GNULEX, June 1, 1988), age is unclear. May be older than Lamotte Sandstone, may be the basal conglomerate of Lamotte Sandstone, or may be younger than Lamotte. Silurian age suggested by most recent author (1901).]
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 ([ ]).