| Basis for focus area |
Extent of the Potomac Terrane in Maryland, which is bounded on the west by the Pleasant Grove fault, and covered by Cretaceous and Tertiary Coastal Plain deposits on the east. |
| Identified resources |
Historical production of gold. |
| Production |
Unknown. |
| Status |
Past mining. |
| Estimated resources |
Unknown. |
| Geologic maps |
Southworth and others (2008), scale 1:100,000; Lyttle and others (2017), scale 1:100,000; Cloos and Cooke (1953), scale 1:62,500; Crowley and others (1976), scale 1:62,500; Edwards (1993), scale 1:62,500; Higgins and Conant (1990), scale 1:62,500; Jonas (1928), scale 1:62,500; Southwick and Owens (1968), scale 1:62,500; Froelich (1975), scale 1:62,500; Kuff (1981), scale 1:24,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
Rock units of the Potomac Terrane. |
| Deposits |
Montgomery County gold mines; Maryland mine (MRDS dep_id: 10068001), Bethesda mine (MRDS dep_id: 10068003), Harrison mine (MRDS dep_id: 10068004), Irma mine (MRDS dep_id: 10068006); many more in MRDS. |
| Evidence from mineral occurrences |
MRDS; Maryland Geological Survey. |
| Geochemical evidence |
Favorable mineralogy and rock type. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Unknown. |
| Comments |
Many old mine sites now in urbanized areas. |
| Cover thickness and description |
Variable cover and saprolite, some urban areas. |
| Authors |
Rebecca Kavage Adams, William Junkin, David K. Brezinski, Stephen G. Shank. |
| New data needs |
Geophysical data, geologic mapping, and geochemical analyses. |
| Geologic mapping and modeling needs |
Geologic mapping of 7.5-minute quadrangles (1:24,000 scale), but incomplete. |
| Geophysical survey and modeling needs |
A high-resolution airborne magnetic and radiometric survey with approximately 200 m line spacing. |
| Digital elevation data needs |
Lidar mostly complete except for Baltimore County (Maryland) where it is planned and funded. |
