Three broadly interrelated problems of critical significance to the proper interpretation of melt inclusion (MI) data are addressed in this thesis. The first issue, the petrogenesis of anorthitic plagioclase phenocrysts in MORB lavas, has relevance due to the presence of numerous MI in many high-An feldspars. This problem was addressed...
This project explores mechanisms governing the invasion of fluvial systems by two
contrasting exotic species in stream networks of steep, relatively remote forested landscapes
of western Oregon. This research addresses hypotheses relating limitations of seed source
locations, seed transport processes, and sink availability to the distributions of scotch broom
(Cytisus...
Feeder dikes to the Columbia River Basalt Group (CRBG) large igneous province provide a rare opportunity to examine magma transport through the shallow crust during flood basalt eruptions. Over 70% of the CRBG erupted from the Chief Joseph dike swarm, which is exposed across southeastern Washington, eastern Oregon, and western...
Geomorphic change along the lower Clackamas River is occurring at
a millennial scale due to climate change; a decadal scale as a result River
Mill Dam operation; and at an annual scale since 1996 due to a meander
cutoff. Channel response to these three mechanisms is incision.
Holocene strath terraces,...
Concentration of carbon dioxide (CO₂) in the atmosphere has increased over the past 150 years. Because CO₂ is one of a number of radiatively active gases, there is concern that global temperatures will rise and climatic conditions will change. Recent research indicates northern hemisphere forests may currently be accumulating carbon...