Several different petrological techniques have been applied to lava flows between
200 to 475,000 years old from Mount Hood, Oregon. Mount Hood is unusual, in comparison to nearby Mount St. Helens and Mount Jefferson, in that it has produced relatively homogeneous lava compositions over 475,000 years. Erupted lavas are mostly...
A large, damaging earthquake in 1944 on a blind thrust fault caused 60 cm of surface rupture on the subsidiary La Laja fault and additional unmeasured growth of an associated backlimb fold. Both the fold and fault are components of the La Laja Fault System (LLFS) located 25 km northeast...
The Early Oligocene Oregon Coast Range Intrusions (OCRI) consist of gabbroic rocks and lesser alkalic intrusive bodies that were emplaced in marine sedimentary units and volcanic sequences within a Tertiary Cascadia forearc basin. The alkalic intrusions include nepheline syenite, camptonite, and alkaline basalt. The gabbros occur as dikes and differentiated...
The basaltic landscapes of the Oregon High Cascades form a natural laboratory for examining how geologic setting and history influence groundwater flowpaths, streamflow sensitivity to climate, and landscape evolution. In the High Cascades, highly permeable young basaltic lavas form extensive aquifers. These aquifers are the dominant sources of summer streamflow...
This thesis develops a geology training manual for the Interpretation staff of Craters of the Moon National Monument and Preserve (CRMO) in southern Idaho. The manual will help the staff convey geologic principles to park visitors who are experiencing a landscape formed by volcanic processes. Basic geology and the most...
This thesis focuses on the application of the cosmogenic nuclide Beryllium-10 (10Be) in an effort to better constrain the thickness history of the Fennoscandian Ice Sheet (FIS) at the Last Glacial Maximum (LGM) and into the Holocene, as well as begin to answer the long-standing question regarding the age
and...
Groundwater nitrate contamination is a well-documented issue in the Southern Willamette Valley (SWV) of Oregon, as a Groundwater Management Area (GWMA) has recently been declared. As a GWMA, groundwater nitrate monitoring must occur until regional concentrations are below 7 mg/L NO3-N. However, the presence of temporal variability can make it...
Magmatic sulfides from Yerington, Nevada, and Yanacocha, Peru, were analyzed by laser ablation-inductively coupled mass spectrometry (LA-ICPMS) and electron microprobe to determine copper, gold, and silver concentrations and ratios in order to examine the relationship to the metal content of related magmatic-hydrothermal ores. The magmatic sulfides occur in plutonic rocks...
The primary goal of this study is to assess the impact of a subduction component
added to the mantle wedge beneath the Oregon Cascades to the composition and fO2 of
primitive Cascade basalts. Olivine-hosted melt inclusions from compositionally diverse
basalts across the Cascade arc (~100 km) are utilized in an...
Dam removal is increasingly viewed as a river restoration tool because dams affect so many aspects of river hydrology, geomorphology, and ecology; but removal also has impacts. When a dam is removed, sediment accumulated over a dam’s lifetime may be transported downstream; and the timing, fate and consequences of this...