dc.contributor.author	Essex, Richard M.	en
dc.contributor.committeechair	Sinha, A. Krishna	en
dc.contributor.committeemember	Beard, James S.	en
dc.contributor.committeemember	Eriksson, Susan C.	en
dc.contributor.department	Geology	en
dc.date.accessioned	2014-03-14T21:32:26Z	en
dc.date.adate	2010-03-30	en
dc.date.available	2014-03-14T21:32:26Z	en
dc.date.issued	1992-06-15	en
dc.date.rdate	2010-03-30	en
dc.date.sdate	2010-03-30	en
dc.description.abstract	The Striped Rock granite pluton is an epizonal A-type intrusion emplaced into Grenville age gneisses at 748 Ma. Isotopic, petrographic, and textural evidence indicate that the facies comprising this pluton are differentiates of a homogeneous magrna and not the result of multiple intrusions. Strontium isotopic data preclude the Striped Rock granite from being a partial melt of basement gneisses similar to those presently exposed in the Blue Ridge province. Isotopic data also suggest that it is unlikely that the Striped Rock granite formed by simple differentiation of a mantle derived melt. Of the many models proposed for the petrogenesis of A-type granites the models that are most consistent with the physical and chemical characteristics of Striped Rock granite are those employing interaction between a basaltic magma and an evolved crustal source. Of particular interest, here, is the Inodel proposed by Barker et al. (1975) for the formation of the Pikes Peak batholith. The environment of formation, intensive variables (as interpreted from petrographic studies), mineralogy, and chemistry of the fayalite free granite of Pikes Peak and the Striped Rock granite closely parallel one another, suggesting a similar process for their formation. The "reaction melting" process outlined by Barker et al. (1975) is consistent with both isotopic and limited trace element data from Striped Rock granite. The Striped Rock granite is part of the Late Precambdan Magmatic Province (LPMP). A detailed study of Striped Rock granite has allowed this pluton to be compared and contrasted with other LPMP rocks. This comparison has lead to the recognition of two distinctly different categories of late Precanlbrian felsic intrusives; (i) Crossnore-Lansing type (Crossnore and Lansing granites) and (ii) Striped Rock type (Striped Rock, Beech, and Stewartsville(?) granites). Crossnore-Lansing type granites are characterized by small volumes (as inferred from areal distribution, ~lkm²), high Sr initial ratio, sodic amphibole, and multiple zircon populations. Striped Rock type granites are characterized by relatively large volumes (>65km²), intermediate Sr initial ratio, a single zircon population, and hornblende, where amphibole is present. Recent radiometric age determinations support a temporal relationship between Striped Rock type granites. The age of formation for the Striped Rock granite, determined here, strongly supports the emerging model that late Precambrian magmatism associated with extensional tectonism occurred in at least two pulses. The earlier pulse of magmatism was dominated by felsic intrusives and lasted for 60 My between 760 Ma and 700 Ma. The Second pulse of magmatism was dominated by basaltic magmatism and occurred approximately at 570 Ma. This later magmatic event was probably related to the opening of the Iapetus ocean.	en
dc.description.degree	Master of Science	en
dc.format.extent	vi, 98 leaves	en
dc.format.medium	BTD	en
dc.format.mimetype	application/pdf	en
dc.identifier.other	etd-03302010-020037	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-03302010-020037/	en
dc.identifier.uri	http://hdl.handle.net/10919/41800	en
dc.language.iso	en	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	LD5655.V855_1992.E873.pdf	en
dc.relation.haspart	LD5655.V855_1992.E873_drw01.pdf	en
dc.relation.haspart	LD5655.V855_1992.E873_drw02.pdf	en
dc.relation.haspart	LD5655.V855_1992.E873_drw03.pdf	en
dc.relation.isformatof	OCLC# 26487356	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject.lcc	LD5655.V855 1992.E873	en
dc.subject.lcsh	Granite -- Virginia -- Grayson County	en
dc.subject.lcsh	Petrogenesis -- Virginia -- Grayson County	en
dc.title	Age and petrogenesis of the Striped Rock granite pluton: Blue Ridge province, southwestern Virginia	en
dc.type	Thesis	en
dc.type.dcmitype	Text	en
thesis.degree.discipline	Geology	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en

Age and petrogenesis of the Striped Rock granite pluton: Blue Ridge province, southwestern Virginia

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