| State | Maryland |
|---|---|
| Name | Ellicott City Granodiorite |
| Geologic age | Silurian |
| Lithologic constituents |
Major
Igneous > Plutonic > Syenitic > Quartz-monzonite
Minor
Igneous > Plutonic > Granitic > Granodiorite
|
| Comments | Radiogenic date from Wetherill et al., 1966 (ref. MD003). Also second age date reference from USGS Geologic Names lexicon (ref. MD004): Isotopic dating (Rb-Sr) of the Ellicott City Granodiorite indicates the unit is of Silurian age (425 Ma). |
| References | Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.Wetherill, G.W., Tilton, G.R., Davis, G.L., Hart, S.R., and Hopson, C.A., 1966, Age measurements in the Maryland Piedmont: Journal of Geophysical Research, v. 71, p. 2139-2155.USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/https://ngmdb.usgs.gov/Geolex/search |
| NGMDB product | |
| Counties | Baltimore - Howard |