- Usage in publication:
-
- Gunpowder granite*
- Modifications:
-
- Named
- Dominant lithology:
-
- Granite
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Name Gunpowder granite applied to medium-grained potassic granite that intrudes Glenarm series in Baltimore Co., MD. Contains biotite and muscovite in varying proportions. Assigned to the late Precambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Gunpowder Gneiss
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Unit referred to as Gunpowder Gneiss [in agreement with recent State usage]. May be intrusive sill in Rush Brook Member of Loch Raven Schist (Cambrian-Ordovician(?)). Age modified to Ordovician based on 450 m.y. date from Concordia plot.
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 ([ ]).