- Usage in publication:
-
- Onyx Cave Member*
- Modifications:
-
- Named
- Biostratigraphic dating
- Dominant lithology:
-
- Limestone
- Conglomerate
- Shale
- Dolostone
- AAPG geologic province:
-
- Appalachian basin
Summary:
The Onyx Cave Member of the Virginville Formation, here named in the Richmond slice of the Hamburg klippe in PA, consists of four distinct rock types: 19 granular and quartzose limestone, 2) interbedded black lime mudstone and limestone, 3) massive carbonate-clast conglomerate, and 4) laminated black shale and orange dolostone. Conformably overlies the Sacony Member of the Virginville; tectonically overlies the Moselem Member of the Virginville. Minimum thickness is 90 m. Age is Late Cambrian to Early Ordovician, based on conodonts.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Onyx Cave Member*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Appalachian basin
Summary:
Age of the Virginville Formation is Late Cambrian and Middle Ordovician. The lower Sacony Member and conformably overlying Onyx Cave Member are Late Cambrian. They tectonically overlie the Moselem Member which contains Middle Ordovician fossils. Lower Ordovician strata appear to be missing.
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 ([ ]).