(BB) Boulder Batholith Suite -- Montana
Title
(BB) Boulder Batholith Suite -- Montana
Collection Items
Rhyolite
intrusive plug of quartz monzonite
Andesite
pre-batholith volcanic
Rhyolite dike
from nearly vertical dike cutting quartz monzonite
Quartz monzonite
fine grained with pinkish tint
Granogabbro
from large sill
Rhyolite
flinty, columnar jointing, post-batholith volcanic
Obsidian vitrophyre
ignimbrite layer in a welded tuff
Quartz monzonite
coarse grained, light gray, biotite-hornblende
Aplite
iron-stained
Quartz monzonite
fine grained, dark gray, porphyritic
Quartz monzonite
porphyritic, light gray, fine grained
Quartz latite
intrusive