Pre-Grenville ages of basement rocks in central Virginia: a model for the interpretation of zircon ages

dc.contributor.authorDavis, Robert Gordonen
dc.contributor.departmentGeological Sciencesen
dc.date.accessioned2016-04-07T15:31:08Zen
dc.date.available2016-04-07T15:31:08Zen
dc.date.issued1974en
dc.description.abstractLate to Middle Precambrian basement rocks in the Blue Ridge of Central Virginia represent a heterogeneous admixture of highly deformed gneisses, paragneisses and igneous intrusives, which have undergone multiple periods of metamorphism. Isotopic U-Pb age determinations on the Lovingston Formation indicate that portions of these Central Appalachian basement rocks are 1633 m.y. old and may be as old as 1870 m.y. A concordant zircon from the Lovingston gneiss indicates that intense regional metamorphism occurred at least 913 m.y. ago. The Rockfish granodiorite, in Nelson County, Virginia, intruded these older basement rocks 820 ± 20 m.y. ago and appears to be coeval with the extensive Catoctin and Mt. Rodgers volcanic rocks. Because of the complex geologic history of this area, two models are proposed to explain the U-Pb zircon data. The first model proposes that the different rock types within the Lovingston Formation were all crystallized at least 1633 m.y. ago and have each responded in a different manner to multiple periods of metamorphism and at least one period of plutonism. The second model is a direct interpretation.en
dc.description.degreeMaster of Scienceen
dc.format.extentiv, 46 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.urihttp://hdl.handle.net/10919/65044en
dc.language.isoenen
dc.publisherVirginia Polytechnic Institute and State Universityen
dc.relation.isformatofOCLC# 38967847en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1974.D38en
dc.titlePre-Grenville ages of basement rocks in central Virginia: a model for the interpretation of zircon agesen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineGeological Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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