- Usage in publication:
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- Ta River Metamorphic Suite*
- Modifications:
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- Named
- Dominant lithology:
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- Gneiss
- Schist
- Metagabbro
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Named as part of Fredericksburg Complex. Named for Ta River, which cuts through typical exposures, Spotsylvania Co., eastern VA. Northernmost part of the suite consists of amphibolitic gneiss associated with conformable granitoid rocks and smaller amounts of biotite gneiss and schist. To the southwest, contains more biotite gneiss and schist and smaller amounts of amphibolite gneiss. Coarse-grained metagabbro is exposed along Long Branch in Brokenburg quad. Contact with Holly Corner Gneiss (new) is gradational and difficult to establish. Based on its possible correlation with Chopawamsic Formation, age is Early Cambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Ta River Metamorphic Suite
- Modifications:
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- Overview
- Areal extent
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Ta River Metamorphic Suite is mapped in Spotsylvania, Louisa, Goochland, and easternmost Fluvanna Cos. Fredericksburg Complex not used on the map nor mentioned in the text. Unit is mapped undivided and consists of a layered sequence of greenish-gray to black, medium- to coarse-grained, poorly to well-lineated, massive to well-layered amphibolite and amphibole-bearing gneiss and schist. Includes ferruginous quartzite, and minor biotite gneiss, felsic volcanic rocks, gabbro, and granite.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
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- Ta River Metamorphic Suite*
- Modifications:
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- Age modified
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Age of Ta River Metamorphic Suite changed from Cambrian(?) of Pavlides (1980) to Cambrian, based on equivalence to Chopawamsic Formation.
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 ([ ]).