- Usage in publication:
-
- Viopuli ignimbrite member
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
-
- Latite
- Rhyodacite
- AAPG geologic province:
-
- Basin-and-Range province
Summary:
Named as the basal member of the Roskruge volcanics for the village of Viopuli in the southwestern part of the Roskruge Mountains in Pima Co, AZ in the Basin-and-Range province. No type locality designated. Overlies the Cretaceous Roadside formation. Underlies the unnamed upper ash-flow sheet of the Roskruge. The new member is the lower bright red ash-flow sheet intercalated with air-fall tuffs and breccias. Of quartz latitic to rhyodacitic composition. Has an age of 74.1 +/-1.5 to 74.2 +/-1.5 m.y.
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 ([ ]).