- Usage in publication:
-
- Ellicott City granite
- Modifications:
-
- Named
- Dominant lithology:
-
- Granite
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Named the Ellicott City granite for Ellicott City, Baltimore Co., northeastern MD. Unit is a narrow outcrop of massive biotite-quartz monzonite that is very similar in appearance to the Woodstock granite. Intrudes the Wissahickon formation. Age may be as late as late Paleozoic.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Ellicott City Granodiorite
- Modifications:
-
- Age modified
- Geochronologic dating
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Isotopic dating (Rb-Sr) of the Ellicott City Granodiorite indicates the unit is of Silurian age (425 Ma).
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Ellicott City Granodiorite*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
The Ellicott City Granodiorite is considered of Ordovician age based on its relationship to the Guilford Granite and Woodstock Granite. Unit appears on generalized geologic map of MD Piedmont.
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 ([ ]).