- Usage in publication:
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- Pina Siltstone Member*
- Modifications:
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- Named
- Dominant lithology:
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- Siltstone
Summary:
The El Ocho Formation, here named, consists of a coarsely stratified sequence of massive to thick-bedded volcanic breccia and tuff with andesitic lava flows and flow breccias near the base exposed in a complexly faulted belt across the northern part of the Naranjito quadrangle. A basal siltstone member is here named the Pina Siltstone Member. Consists of thin-bedded to laminated calcareous siltstone with interbedded volcanic wacke. Thickness is 180 m. Age is Early and Late Cretaceous based on correlation with the Robles Formation.
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 ([ ]).