Crossbedding of the Potomac Formation in Fairfax County, Virginia
Open-File Report
76-193
By: Gordon Whitney Weir
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Abstract
Crossbedding in sandstone units is the most conspicuous sedimentary structure of the Potomac Formation in Fairfax County, Virginia. Most sets of crossbeds are a few feet thick and several feet wide and tens of feet long. Trough sets are dominant, but planar sets are also common. Dip directions of crossbeds show great variation, though westerly dips are sparse. The averages (resultant vectors) of crossbedding dip-directions measured at 33 localities do not show significant differences according to their geographic or stratigraphic distribution. The average dip-direction of the 292 crossbeds measured is N. 85? E. The data suggest that the depositional slope was easterly in Fairfax County throughout the time of deposition of the Potomac Formation. Major sand bodies, potential aquifers of the formation, are probably elongated along easterly trends.
Suggested Citation
Weir, G.W., 1976, Crossbedding of the Potomac Formation in Fairfax County, Virginia: U.S. Geological Survey Open-File Report 76-193, 29 leaves :folded ill., folded col. map ;27 cm.; (28 p., 1 sheet, scale 1:48,000 - PGS), https://doi.org/10.3133/ofr76193.
ISSN: 2331-1258 (online)
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Crossbedding of the Potomac Formation in Fairfax County, Virginia |
| Series title | Open-File Report |
| Series number | 76-193 |
| DOI | 10.3133/ofr76193 |
| Year Published | 1976 |
| Language | ENGLISH |
| Publisher | U.S. Geological Survey, |
| Description | 29 leaves :folded ill., folded col. map ;27 cm.; (28 p., 1 sheet, scale 1:48,000 - PGS) |
| Scale | 48000 |