- Usage in publication:
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- Little Creek formation
- Modifications:
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- Named
- Dominant lithology:
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- Latite
- AAPG geologic province:
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- Midcontinent region
Summary:
Named as an informal field term. [Rank term "formation" should not be used after geographic name for informal units.] Derivation of name not stated. Mapped in Ketcherside Mountain area in southern St. Francois Mountains, southeast MO, Midcontinent region. Consists of medium to dark gray porphyritic latite with buff-colored phenocrysts of plagioclase (8.8%) and perthitic orthoclase (10.2%); matrix is fairly homogeneous except for minor secondary quartz. Probably originated as ash-flow tuff. Overlies unnamed rhyolite; underlies Glover formation (new, informal field term) [rank term "formation" should not be used after geographic name for informal units]. Little Creek and Glover replace Royal Gorge Rhyolite (not used) of Tolman and Robertson (1969). Table 1 is comparison of nomenclature used in area. Detailed petrographic description in Appendix 1. Precambrian age.
[Authors' intentions are unclear as to which, if any, of the geologic units discussed should have formal status.]
Source: 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 ([ ]).