- Usage in publication:
-
- Hickory Grove Basalt*
- Modifications:
-
- Named
- Dominant lithology:
-
- Basalt
- Sandstone
- Siltstone
- AAPG geologic province:
-
- Culpeper basin
- Piedmont-Blue Ridge province
Summary:
Following the informal usage of Lee (1979, 1980), the middle sequence of basalt flows, extending for 62 km (38 mi) in the western part of the Culpeper basin, is named the Hickory Grove Basalt of the Culpeper Group. It consists of two or more flows of tholeiitic basalt with interbedded lenses of sandstone and siltstone. It is the least altered of the Culpeper basin basalts. It disconformably or paraconformably overlies the Midland Formation and disconformably or paraconformably underlies the Turkey Run Formation. Thickness ranges from 50 to 300 m (160 to 1,000 ft). Age is Early Jurassic (Hettangian) based on its stratigraphic position between dated Early Jurassic palyniferous formations.
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 ([ ]).