| Catoctin Formation | |
|---|---|
| Stratigraphic range: Ediacaran | |
 | |
| Type | Formation |
| Underlies | Chilhowee Group |
| Overlies | Basement Rock |
| Thickness | 100-400 Feet |
| Location | |
| Region | Virginia, Maryland, and Pennsylvania |
| Country | United States |
| Type section | |
| Named for | Its exposure on Catoctin Mountain |
| Named by | Arthur Keith |
 Geological Map of the Catoctin Formation shown in blue and other formations associated with it. | |
The Catoctin Formation is a geologic formation that expands through Virginia, Maryland, and Pennsylvania.[1] It dates back to the Precambrian and is closely associated with the Harpers Formation, Weverton Formation, and the Loudoun Formation.[1] The Catoctin Formation lies over a granitic basement rock and below the Chilhowee Group[1] making it only exposed on the outer parts of the Blue Ridge.[2] The Catoctin Formation contains metabasalt, metarhyolite,[3] and porphyritic rocks, columnar jointing, low-dipping primary joints, amygdules, sedimentary dikes, and flow breccias.[4] Evidence for past volcanic activity includes columnar basalts and greenstone dikes.
- ^ a b c Reed, John C. (1955-07-01). "Catoctin Formation Near Luray, Virginia". GSA Bulletin. 66 (7): 871–896. doi:10.1130/0016-7606(1955)66[871:CFNLV]2.0.CO;2. ISSN 0016-7606 – via GeoScienceWorld.
- ^ Bloomer, Robert O.; Bloomer, Richard R. (1947-03-01). "The Catoctin Formation in Central Virginia". The Journal of Geology. 55 (2): 94–106. doi:10.1086/625404. ISSN 0022-1376. S2CID 129699878.
- ^ Thurmont, Mailing Address: 6602 Foxville Road; Us, MD 21788 Phone:663-9388 Contact. "Geology - Catoctin Mountain Park (U.S. National Park Service)". www.nps.gov. Retrieved 2021-04-13.
{{cite web}}: CS1 maint: numeric names: authors list (link) - ^ "USGS: Geological Survey Bulletin 1265 (Catoctin Formation)". www.nps.gov. Retrieved 2021-04-13.