John Delano sampling bentonite layers in medial Ordovician black shales of the Utica Formation in Flat Creek, near Canajoharie, NY.
John
Delano sampling bentonite layers in medial Ordovician black shales
of the
Utica Formation in Flat Creek, near Canajoharie, NY.
Image copyright (C) 1995 Stephanie Dannenmann.
Some of the bentonites contain quartz phenocrysts
with pristine rhyolitic glass melt inclusions. For details see:
Delano
J.W., Tice S.J., Mitchell C.E., and Goldman D. (1994) Rhyolitic
glass in
Ordovician K-bentonites: A new stratigraphic tool. Geology,
22,
115-118.
melt inclusions in quartz grains from Mohawk Valley bentonite