- Usage in publication:
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- Libertytown metarhyolite
- Modifications:
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- Named
- Dominant lithology:
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- Metavolcanics
- Rhyolite
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Name Libertytown metarhyolite proposed for rocks mapped as metarhyolite and meta-andesite in Glenarm series on geologic map of Frederick Co., MD (Maryland Geological Survey, 1938). Unit is dense cryptocrystalline rock, purple, bluish-black, or red, with macrophenocrysts of pink or white feldspar and glassy quartz in dense groundmass. Interbedded with blue and purple meta-andesite containing amygdules commonly filled with white, pink, or green calcite having an outer film of sericite or chlorite. Overlies Wakefield marble and interfingers with Sams Creek metabasalt (new) and Ijamsville phyllite. Age is Precambrian(?).
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Libertytown metarhyolite
- Modifications:
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- Overview
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Volcanic series in eastern part of Piedmont province includes Sams Creek metabasalt, Libertytown metarhyolite, Ijamsville phyllite, and Urbana phyllite. Quartzites occur in all members. Some quartzites pass directly from Ijamsville into the Urbana and into the Libertytown, and from the Urbana into the Sams Creek, indicating relative contemporaneity of these formations, all of which are apparently equivalent to Harpers formation. Age is late Precambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Libertytown Metarhyolite*
- Modifications:
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- Age modified
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Libertytown Metarhyolite of western MD overlies Wakefield Marble and interfingers with Sams Creek Formation and Ijamsville Phyllite. Age is no younger than Ordovician [early Paleozoic].
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Libertytown Metarhyolite
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Age of Libertytown Metarhyolite in Frederick Co. is listed in table as Late 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 ([ ]).