- Usage in publication:
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- Glenarm series*
- Modifications:
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- Named
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Glenarm is name given to provincial series of pre-Cambrian metamorphosed sedimentary rocks present in northern VA, MD, southeastern PA, western NJ, and possibly southeastern NY. Formerly assigned to "Algonkian system," but that term has now been discarded. [No lithology given.]
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Glenarm Supergroup
- Modifications:
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- Revised
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Glenarm Series is here revised to Glenarm Supergroup in MD and subdivided into Setters Formation, Cockeysville Marble, and Wissahickon Group. The Wissahickon is raised in rank in this report and subdivided into six formations, five of them newly named. Age of the Glenarm shown as Cambrian to Ordovician(?).
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Glenarm Group*
- Modifications:
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- Revised
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Following Drake (1986, Geological Society of America, Abstracts with Programs, v. 17, no. 7, p. 566), Glenarm Group consists of Setters Formation, Cockeysville Marble, and Loch Raven Schist. The Oella Formation is part of an overlying thrust stack and not part of the Glenarm. Glenarm Group was deposited over Baltimore Gneiss.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Glenarm
- Modifications:
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- Not used
Summary:
Use of terms Wissahickon Group and Glenarm Supergroup discontinued in MD. Baltimore terrane cover sequence is described using individual formation names.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Glenarm Supergroup
- Modifications:
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- Revised
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Detailed analysis of field relations at five locations near Doe Run reveal that Wissahickon Group consistently lies above, and with angular contact upon, an overturned stratigraphic sequence of Grenville-aged gneiss above Setters Formation, which lies above Cockeysville Marble, all three assigned here to the Brandywine terrane. Evidence supports the theory that the Wissahickon Group was emplaced after peak metamorphism. Identification of the Doe Run thrust fault at the base of the Wissahickon contradicts the previous assumption of stratigraphic continuity throughout the Glenarm Supergroup of southeastern PA and DE.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Glenarm Group*
- Modifications:
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- Revised
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Glenarm Group was redefined by Drake (1986) and Drake and others (1989) as containing Setters Formation, Cockeysville Marble, and Loch Raven Schist. Loch Raven Schist is here removed from Glenarm Group because current work shows that Loch Raven Schist is thrust over either Cockeysville Marble, Setters Formation, Baltimore Gneiss, or Laurel Formation. The Glenarm sequence consisting of schist of the Setters, quartzite of the Setters, and Cockeysville Marble is exactly the same as that of Pine Mountain Group in AL, which consists of Hollis Quartzite, Manchester Schist, and Chewacla Marble (Higgins and others, 1988), the cover sequence on Laurentian basement in Pine Mountain window.
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 ([ ]).