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Braintree Intrusive Complex - biotite-bearing metagranodiorite, metagranite, and meta-aplite of the Mount Nevis pluton (VTSbg;0)

Geologic Formation near Randolph, VT

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Geologic Age

Homerian – Lockhovian (428 Ma – 414 Ma ago)

Geologic Unit Label

Sbg

Yellowish-gray to light-gray, medium- to coarse-grained magnetite-biotite-mesoperthite granodiorite and granite having a U-Pb zircon SHRIMP age of 421±7 Ma, no. 38 (Aleinikoff and others, 2011). Has mutually intrusive contacts with associated metadiorites. Unmapped dike of Sbg in the layered, mixed felsic and mafic rocks (Onbm) of the North River Igneous Suite at Bridgewater has a U-Pb zircon age of 418±1 Ma, no. 37 (Aleinikoff and Karabinos, 1990). Part of the Lake Memphremagog Intrusive Suite (425±3 Ma to 418.5±2 Ma).

— USGS

Taxonomy

Classified As

Geologic Formation