Microcline-augen granite and monzogranite gneiss

Gray to whitish-gray, coarse-grained biotite-microcline megacrystic granite and monzogranitic gneiss; passes locally into more equigranular granitic gneiss (Y3Ag) and locally into extensive areas of biotite pegmatoid granitic gneiss (Y3Apg), locally muscovite-bearing. Enclaves of metasedimentary units in these granites and associated gneisses are locally albitized and enriched in magnetite; enclaves of highly aluminous altered rocks now contain restites of chloritoid and abundant sericite. U-Pb zircon ages of 1,119±3.3 Ma (no. 15) and 1,121±1.4 Ma (no. 14) determined on samples near Sherburne Center and on Telegraph Hill east of Chittenden Reservoir by Karabinos and Aleinikoff (1990). Chittenden Intrusive Suite (1,149±8 Ma to 1,119±3 Ma). Mount Holly Complex intrusive rocks. Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes.
State Vermont
Name Microcline-augen granite and monzogranite gneiss
Geologic age Late Mesoproterozoic
Lithologic constituents
Major
Metamorphic > Metasedimentary > ParagneissGray to whitish-gray, coarse-grained biotite-microcline megacrystic granite and monzogranitic gneiss.
References
NGMDB product
Counties Addison - Rutland - Windsor