- Usage in publication:
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- Moredock Member
- Modifications:
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- Original reference
- Dominant lithology:
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- Calcarenite
- AAPG geologic province:
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- Illinois basin
Summary:
Pg. 124-125,238-239. Moredock Member of Dunleith Formation. Consists mostly of coarse-grained calcarenite. Thickness commonly 60 to 70 feet. Overlies Eagle Point Member; underlies New London Member (new). Where New London is missing the Moredock is overlain unconformably by Cincinnatian strata, either Cape Limestone, Elgin Shale, or Thebes Sandstone. At type section underlies Cape Limestone. Is a previously undifferentiated part of Kimmswick Limestone and is equivalent to Fairplay, Mortimer, and Rivoli Members of northern outcrop area. Age is Middle Ordovician (Champlainian).
Type section: quarry of Columbia Quarry Company, and exposure in Mississippi River bluff, just north of crushing plant, center north line SW/4 sec. 3, T. 3 S., R. 11 W., Kimmswick quadrangle. Named from Moredock Lake at Valmeyer, Monroe Co., southwestern IL.
Source: US geologic names lexicon (USGS Bull. 1350, p. 503).
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 ([ ]).