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Geological Society of America Centennial Field Guide—Northeastern Section, 1987Barre granite quarries, Barre, VermontDorothy A. Richter, Hager-Richter Geoscience, Inc., P.O. Box 572, Windham, New Hampshire 03087LOCATIONThe Barre granite quarry district is located in the southeast-ern section of Barre Town, Washington County, Vermont, nearthe villages of Graniteville and Websterville. The quarried areaextends slightly into the northeastern corner of Williamstown,Orange County. Figure 1 shows the general location of thequarry district and the various village entities within Barre Town.From I-89 the area is reached by taking Exit 6 (Barre, SouthBarre) and following the access road 5 mi (8 km) to the intersec-tion with Vermont 14 (Fig. 1). Cross Vermont 14 and followMiddle Road to Graniteville.Figure 2 shows the locations of the quarries discussed in thisfield guide. Public viewing platforms are available at the edgeof the Rock of Ages quarry (behind the Rock of Ages VisitorsCenter, 0.9 mi [1.5 km] east of Lower Graniteville) and theWells-Lamson quarry (along the Websterville Road at the northend of the quarry). During the summer months, Rock of Agesoperates a short train ride for tourists that gives an excellent viewof the active Smith Quarry and the abandoned Duffee Quarry.Access to the several other active and abandoned granitequarries in the area may be obtained only by making prior ar-rangements with the Rock of Ages Corporation and theFigure 1. Location of Barre quarry district and numerous villages withinthe boundaries of Barre Town, Vermont.Wells-Lamson Quarry Company. Both companies are accom-modating to serious visitors and researchers who wish to dodetailed sampling or mapping. The Pirie/Adam, Smith, andWetmore & Morse quarries are especially interesting to visit.There are more than 70 inactive quarries in the Barre area, butmost are now filled with water; in fact, many are a part of thelocal public water supply. Dale (1923) provided a map showingthe locations and names of many of the quarries active at thattime.SIGNIFICANCEThe Barre granite quarries expose a three-dimensional viewof a small, well-studied pluton of the New Hampshire PlutonicSeries. It is a Devonian talc-alkaline pluton formed by partialmelting of Siluro-Devonian sedimentary rocks that had beenfolded and regionally metamorphosed during the Acadian orog-eny and thus illustrates that the orogeny occurred rather suddenlyin the region.Contact relations with the Siluro-Devonian Gile MountainFormation, internal igneous flow features, and various types ofpostconsolidation fracturing are very well displayed in the quar-ries. In addition, the Barre quarry district is one of the few locali-ties in the Northeast U.S. where geologists and the public canobserve the ancient and honorable tradition of quarrying large-dimension stone blocks.REGIONAL SETTINGThe Connecticut Valley-Gaspé synclinorium in easternVermont is characterized by tightly folded phyllitic and calcare-ous metasediments of the Gile Mountain and Waits River forma-tions. The metasediments are generally interpreted to have beendeposited in the remnants of the Iapetus ocean. A series of morethan 20 two-feldspar, two-mica granitoids, ranging in size fromsmall dikes <0.6 mi (< 1 km) long to plutons >37 mi (>60 km)in diameter, intrude the metasediments in eastern Vermont. Ingeneral, the plutons are unzoned, internally uniform in composi-tion, and not associated with igneous rocks more mafic in compo-sition than diorite.Contacts with the metasediments are mildly to strongly dis-cordant. Metamorphic aureoles are associated with most of theintrusions (including the Barre pluton), indicating that the plutonswere intruded after the peak of regional metamorphism. Theregional metamorphic grade of the host metasediments rangesfrom garnet to kyanite grade in central Vermont. The regionalmetamorphic grade around the Barre pluton is staurolite grade.Naylor (1971) obtained K-Ar dates on primary micas in239240D. A. RichterFigure 2. Sketch map showing quarry locations discussed in text.several of the Vermont granitoids (including the Barre pluton)that clustered around 380 Ma. He concluded that the Acadianerogenic event in that part of the northern Appalachians musthave been a brief but intense event, since the Devonian granitoidscrosscut Devonian sediments that had been folded and regionallymetamorphosed before intrusion.BARRE AREAFigure 3 is a generalized geologic map of the Barre areamodified from Murthy (1957) and Doll and others (1961). TheBarre pluton is contorted in outline but is approximately 1.9 mi(3 km) wide and 5 mi (8 km) long. The pluton is elongatedparallel to the regional strike of the enclosing metasediments, theGile Mountain Formation for the most part, and the Waits RiverFormation for a segment of the eastern contact. A much largerigneous body of similar composition, the Knox Mountain pluton,occurs a few miles northeast of the Barre pluton.The Gile Mountain Formation is composed of fine-grained,dark gray mica schists and micaceous quartzites. The Waits RiverFormation contains similar rocks plus abundant caleareousschists. The stratigraphic relationships between the two host for-mations are complex and contradictory in places. Woodland(1977) and Fisher and Karabinos (1980) determined from struc-tural analysis and graded bedding in the Royalton area, approxi-mately 31 mi (50 km) south of Barre, that the Gile MountainFormation is younger than the Waits River Formation and thatthe belt of Gile Mountain Formation in which most of the Barrepluton resides is the core of a north-plunging synform. Woodland(1977) has further suggested that the synform is the downward-facing nose of a recumbent nappe with an eastward root zone.Contacts of the PlutonFoliation of the metasediments near the Barre pluton isnearly vertical, strikes north-northeast, and more or less bulgesaround the igneous rock. The contacts of the pluton are thussemiconcordant with the foliation in most places. It appears thatthe pluton gently “shouldered” itself into position along zones ofweakness in the country rock. Large xenoliths (>6 ft or >2 m)that appear not to have been reoriented are common, and septa ofthe metasediments (possible roof pendants) are present within thepluton.A good pavement exposure of the contact occurs behind thestorage garages at the south end of the Pirie quarry. The contact isexposed in places along the east walls of the Rock of Ages andPirie quarries where


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