- Usage in publication:
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- Elkport Bentonite Bed
- Modifications:
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- Original reference
- Dominant lithology:
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- Bentonite
- AAPG geologic province:
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- Iowa shelf
Summary:
Pg. 45. Elkport Bentonite Bed of Glenhaven Member of Guttenberg Formation. Present in Iowa, Illinois, and Wisconsin. Consists of gray bentonite clay; thickness 0.03 m at type section. Is basal unit of Glenhaven Member; overlies Garnavillo Member of Guttenberg. Age is Middle Ordovician.
Type section: Guttenberg North Section, roadcut on U.S. Highway 52, northwest of Guttenberg, in SW/4 SW/4 sec. 5, T. 92 N., R. 2 W., Clayton Co., northeast IA. Named from town of Elkport, 14.5 km southwest of type section.
Source: US geologic names lexicon (USGS Bull. 1564, p. 54).
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 ([ ]).