- Usage in publication:
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- Urbana phyllite*
- Modifications:
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- Named
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Named the Urbana phyllite for Urbana, Frederick Co., MD. Consists of green ferruginous quartzose chlorite phyllite with green slaty layers and is probably pyroclastic facies of associated metabasalt; contains many sericitic quartzite layers, some thin calcareous layers, and infolded quartzite similar to that associated with the Ijamsville phyllite. Underlies the Sugarloaf Mountain Quartzite. The Urbana is of Precambrian(?) age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Urbana Formation*
- Modifications:
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- Overview
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
The Urbana Formation consists of predominantly moderate olive brown to light olive gray metagraywacke and metasiltstone. Unit is poorly sorted, graded bedded, cross-bedded, and calcareous. Also contains light olive gray and light brownish gray fine- to coarse-grained, thin- to medium-bedded, very calcareous sandstone and quartzite and light gray to greenish gray thin-bedded crystalline limestone. Unit overlies the Sugarloaf Mountain Quartzite [different interpretation than Jonas and Stose (1938)] in the Sugarloaf Mountain anticlinorium. Correlates with Lower Cambrian Harpers Formation of the Blue Ridge-South Mountain anticlinorium. Age is Early Cambrian(?).
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 ([ ]).