- Usage in publication:
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- Minguillo Tuff Member*
- Modifications:
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- Named
- Biostratigraphic dating
- Dominant lithology:
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- Tuff
Summary:
The Minguillo Tuff Member of the Pozas Formation, here named, forms a lens of brecciated lava at the base of the Pozas in west-central Ciales quadrangle. Member varies from oxidized murky-red flow breccia to gray porphyritic lava with plagioclase phenocrysts to dark-greenish-gray dense porphyritic rock with pyroxene phenocrysts. Conformably overlies the Manicaboa Formation; underlies the Blacho Tuff Member of the Pozas. Maximum thickness is 300 m. Age is Late Cretaceous (Maastrichtian) based on rudistids in similar rocks.
Source: GNU records (USGS DDS-6; Reston 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 ([ ]).