- Usage in publication:
-
- Brookfield diorite
- Modifications:
-
- Original reference
- Dominant lithology:
-
- Diorite
- AAPG geologic province:
-
- New England province
Summary:
Pg. 107 and map. Brookfield diorite. Extends from near New Milford southward to Bookfield Center, with length of about 8 miles and width of 1 mile. Is usually massive, but shows also gneissoid and even schistose phases. Both light and dark types are present in formation. Intrudes Poughquag quartzite [Lower Cambrian] and the schists of the region [Berkshire and Hoosac, of Ordovician age].
Source: US geologic names lexicon (USGS Bull. 896, p. 273).
- Usage in publication:
-
- Brookfield diorite
- Modifications:
-
- Overview
- AAPG geologic province:
-
- New England province
Summary:
Brookfield diorite is older than Thomaston granite and appears to be younger than Bristol quartz diorite, Hartland schist, and Becket granite gneiss.
Source: US geologic names lexicon (USGS Bull. 896, p. 273).
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 ([ ]).