- Usage in publication:
-
- Mount Pisgah Formation*
- Modifications:
-
- Age modified
- Geochronologic dating
- AAPG geologic province:
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- New England province
Summary:
The age of the Brimfield Group and its Bigelow Brook, Hamilton Reservoir, and Mount Pisgah Formations in this area is considered to be Cambrian? based on the intrusion of 440 Ma Hedgehog Hill gneiss emplaced near the top of the Hamilton Reservoir Formation in the upper part of the Brimfield, although the top of the Brimfield, at least, may be Ordovician or older Paleozoic.
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 ([ ]).