Regionally preserved in a structural basin, rocks of
the Cretaceous Nanaimo Group nonconformably overlie metavolcanic
and metasedimentary rocks of the Permian and older
Sicker Group.
Cretaceous rocks of the thesis area occur in three
formations, the Comox, Extension-Protection, and Cedar Dist;
and, during two cycles, were deposited in environments which,...
Pre-Tertiary metamorphic rocks, Jurassic granitic intrusions,
and Eocene basalts are exposed along the North Fork of the John Day
River at its confluence with Granite Creek. Geochemical and textural
evidence suggest greenschist-metamorphosed, strongly sheared,
volcanogenic rocks originated in an island-arc environment. These
greenstones were apparently intruded during the Late Permian...
During the Late Mississippian-Early Pennsylvanian (latest
Chesterian-early Morrowan), a thick sequence of shallow -water
carbonate-clastic sediments, equivalent to the "Amsden" and lower
Quadrant Formations, was deposited in the Snowcrest trough on the
western margin of the northern Rocky Mountain Cordilleran platform
in southwestern Montana. Today this late Chesterian sequence is...
Clastic sedimentary rocks of the Nanaimo Group on Saltspring Island, British Columbia are Late Cretaceous in age, overlie a deformed and intruded Paleozoic basement complex, and consist of
eight formations. These eight formations, from oldest to youngest, are the Comox, Haslam, Extension-Protection, Cedar District, De Courcy, Northumberland, Geoffrey, and Spray...
Approximately 18 square miles are included in the study area which lies 17 miles southwest of the town of Dillon, Montana. Strata exposed in the area include metamorphic, sedimentary, and volcanic rocks ranging in age from Precambrian to Recent. The Paleozoic and Mesozoic section
is approximately 8000 feet thick and...
The bedrock of North and South Pender Islands, the southernmost islands of British Columbia's Gulf Islands chain, is formed entirely by six formations of the Late Cretaceous Nanaimo Group. These six formations are, from oldest to youngest, the Extens ion- Protection, Cedar District, DeCourcy, Northumberland, Geoffrey, and Spray Formations, A...