Granite and trondhjemite dikes of Chester and Athens domes and west of the Connecticut Valley trough

Light-gray to white, garnet-muscovite-biotite granodiorite at Gassetts quarry, having a U-Pb zircon SHRIMP age of 392±6 Ma, no. 46 (Aleinikoff and others, 2011), from rims on Proterozoic-age cores (J.N. Aleinikoff, USGS, written commun., 2002); and whitish-gray muscovite-rich quartz monzonite and granodiorite, granite pegmatite, and aplite which occur as crosscutting nonfoliated dikes within the core of the domes and as folded and well-foliated dikes on the east and west flanks of the domes; also granite dikes and small stocks of very light gray to white, muscovite-rich, locally garnet-bearing, fine- to medium-grained biotite-muscovite quartz monzonite and granodiorite, locally orbicular, that intrude cover rocks east of the Green Mountain massif from Jamaica to Northfield, including the Liberty Hill locality and the granodiorite stock east of Plymouth. The latter contains inherited zircon with rims having an imprecise SHRIMP age of about 380 to 390 Ma (Aleinikoff and others, 2011); a similar dike south of Plymouth has a U-Pb zircon SHRIMP age of 365±5 Ma, no. 49 (Aleinikoff and others, 2011). These closely resemble undated white granodiorites of the Bethel area and dikes in the Chester and Athens domes; also resemble small dikes of granite, trondhjemite, and quartz monzonite largely west of the Connecti-cut Valley trough. Devonian granitic rocks of southern Vermont. Part of the New Hampshire Plutonic Suite.
State Vermont
Name Granite and trondhjemite dikes of Chester and Athens domes and west of the Connecticut Valley trough
Geologic age Devonian
Lithologic constituents
Major
Igneous > Plutonic > Granitic > GranodioriteLight-gray to white, garnet-muscovite-biotite granodiorite at Gassetts quarry; small stocks of very light gray to white, muscovite-rich, locally garnet-bearing, fine- to medium-grained biotite-muscovite quartz monzonite and granodiorite, locally orbicular.
Igneous > Plutonic > Syenitic > Quartz-monzoniteWhitish-gray muscovite-rich quartz monzonite; locally garnet-bearing, fine- to medium-grained biotite-muscovite quartz monzonite.
Minor
Igneous > Plutonic > Granitic > Leucocratic-granitic > PegmatiteGranite pegmatite, and aplite which occur as crosscutting nonfoliated dikes within the core of the domes and as folded and well-foliated dikes on the east and west flanks of the domes.
Igneous > Plutonic > Granitic > Leucocratic-granitic > ApliteGranite pegmatite, and aplite which occur as crosscutting nonfoliated dikes within the core of the domes and as folded and well-foliated dikes on the east and west flanks of the domes.
Igneous > Plutonic > Granitic > Granite (Dike or sill, Stock or pipe)Also granite dikes and small stocks of very light gray to white, muscovite-rich, locally garnet-bearing, fine- to medium-grained biotite-muscovite quartz monzonite and granodiorite, locally orbicular, that intrude cover rocks east of the Green Mountain massif from Jamaica to Northfield, including the Liberty Hill locality and the granodiorite stock east of Plymouth.
References
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Counties Caledonia - Essex - Rutland - Washington - Windham - Windsor