Skip to Main Content
Book Chapter

The core of the Blue Ridge anticlinorium in northern Virginia

James W. Clarke
James W. Clarke
Search for other works by this author on:
January 01, 1984

Proterozoic Y and Z granitic rocks compose the core of the Blue Ridge anticlinorium in northern Virginia. The oldest units are the Flint Hill Gneiss; an augen-bearing gneiss; the “Pedlar Formation”; and a porphyroblastic granitic gneiss. These appear to have ages in the 1,000-m.y. to 1,100-m.y. range. The porphyroblastic granitic gneiss is in fault contact with the Flint Hill; the Flint Hill grades into the augen-bearing gneiss; and the “Pedlar” appears to be in gradational contact with the Flint Hill. The porphyroblastic granitic gneiss carries xenoliths of an older layered biotite gneiss that lie transverse to the foliation of the host gneiss. The 1,010-m.y.-old Marshall Metagranite intrudes the porphyroblastic granitic gneiss and the Flint Hill Gneiss. Granitic rocks of the 700-m.y.-old Robertson River Formation intrude the Flint Hill Gneiss, the augen-bearing gneiss, and the porphyroblastic granitic gneiss. All units of the core of the anticlinorium are cut by metabasaltic dikes, which are presumed to be feeder dikes for the younger metavolcanic rocks of the Catoctin Formation of the region. The presence of charnockitic rocks in the western part of the core of the anticlinorium indicates that a granulite grade of metamorphism was reached in this terrane. The absence of hypersthene in other rocks of the area may reflect only their chemical and mineral composition. The possibility exists that these disparate-facies rocks were juxtaposed tectonically.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables


GSA Special Papers

The Grenville Event in the Appalachians and Related Topics

Mervin J. Bartholomew
Mervin J. Bartholomew
Search for other works by this author on:
Geological Society of America
ISBN print:
Publication date:
January 01, 1984



A comprehensive resource of eBooks for researchers in the Earth Sciences

Related Articles
This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now