The Juniper Ridge volcanic complex is located in the High Lava Plains Province of
southeastern Oregon, a wide zone of bimodal volcanism and faulting that marks the northern
limit of widespread Basin and Range-style faulting in the northern Great Basin Province. Rhyolite
dome complexes are progressively younger to the northwest...
Volcanic and sedimentary deposits of the Mount Jefferson area (MJA) record a fourmillion-year history of arc-related volcanism related to the subduction of the Juan de Fuca plate beneath North America. 171 mapped stratigraphic units over an area of 150 km² reveal four periods of volcanic activity resulting in diverse composition...
Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt,...
The Paleocene-lower Eocene volcanic rocks of the southern Oregon Coast Range
Roseburg Formation are the oldest remnant eruptive sequence of an oceanic islandseamount
province which is presently exposed along a north-south lineament that stretches
from Vancouver, B.C. into southwestern Oregon. This seamount terrane is thought to
have formed on the...
This study was initiated to characterize the distribution of Fe-Mn nodules and to elucidate trends of Fe, Mn, and P relative to the intensity of the annual cycles of reduction and oxidation. Nodules were enriched in Fe, Mn, and P relative to the soil matrix making them an integral part...