New data are presented that provide evidence for the onset of extensional deformation in the Northwestern Basin and Range within 1 million years after the eruption of the Steens Basalt at 16.5 Ma. New geologic mapping (1:24,000), stratigraphic sections, and ⁴⁰Ar/³⁹Ar dating of the Crane Basin rocks provide a control...
Increasing temperatures in western North America are expected to result in a decline in winter snowpacks, earlier snowmelt, and a shift in the timing of streamflows, with an increasing fraction of streamflows occurring earlier in the water year and drier conditions during the summer. However, few streamflow datasets have associated...
The primary goal of this study is to access the processes that alter primary melts after segregation from a mantle source and ultimately form petrologic Layers 2 and 3 of the Ocean Crust. Mineral, melt inclusion, and whole rock chemical compositions are utilized to further the understanding of 1) the...
Given the growing human security implications resulting from the high rates of change in social-ecological systems, the general question motivating this research is: how can the traditional security establishment respond to rising non-traditional threats? This question comes from the ongoing debate of whether military resources should be used in some...
Surface sediment transport is an important geomorphic process which can be significantly altered by management activities in forested ecosystems. Disturbance of the soil surface may result in increased sediment delivery to fish bearing streams and degradation of soil structure. Selective thinning and low impact yarding techniques were utilized in an...
This research sought to explore the implications of different tenure regimes for both
landscape-level ecological processes and the overall resilience of a social-ecological
system in Central Oregon. The purchase by an investor of former industrial timberlands
known as the Bull Springs tract raised the specter of dispersed residential development on...
Mountain glaciers are receding worldwide with numerous consequences including changing hydrology and geomorphology. This study focuses on changes in glacier area on Mt. Hood, Oregon and Mt. Rainier, Washington where damaging debris flows have occurred in glaciated basins. Landsat imagery is used to map debris-free ice on a decadal time...
A critical link is missing between food production and food consumption. This gap can be overcome by encouraging the production of staple food crops and emphasizing regional and community consumption of locally produced food. In order to re-establish local food security in the Willamette Valley, it is imperative that essential...
Biophysical, socioeconomic and geopolitical pressures from population growth and economic development are leading to an increase in tensions regarding the sharing of water within transboundary basins. Transboundary basins are surface rivers and groundwater resources that are shared among sovereign nations and autonomous regions. This dissertation focuses on surface water in...
Protected natural areas are important reserves for biodiversity, and in the tropics, often play a role in deterring deforestation. This paper evaluates the effectiveness of a protected-area with a
two-tiered management regime in Bolivia, Amboró National Park and Integrated Management Natural Area (IMNA), in deterring clearance of forest. Four satellite...
While the impacts of long-term climate change trends on glacier hydrology have received much attention, little has been done to quantify direct glacier runoff contributions to streamflow. This paper presents an approach for determining glacier runoff contributions to streamflow and estimating the effects of increased temperature and decreased glacier area...
This study examines the impact of two decades of neoliberal policy reform on food production and household livelihood security in three West African countries. The rice sectors in The Gambia, Côte d’Ivoire, and Mali are scrutinized as well as cotton and its relationship to sorghum production in Mali. Although market...
Recent analysis of 38 globally distributed paleoclimatic records covering Marine Isotope Stage 3 (MIS 3) 60–26 ka demonstrated that the two leading empirical orthogonal functions (EOFs) explaining the data are the Greenland ice-core signal (“northern” signal) and the Antarctic ice-core signal (“southern” signal). Here singular spectral analysis (SSA) is used...
Comprehension of eruptive histories is critical in understanding the evolution of magmatic systems at arc volcanoes and may supply evidence to the petrogenesis of intermediate and evolved magmas. Within the 300 ka eruptive history of Mount St. Helens, Washington, the Kalama Eruptive Period, 1479- ~1750 CE was bracketed by interludes...
Comparative investigations based on volcanic morphology suffer from the lack of a large terrestrial baseline for comparison. To fill this gap, the Lava Flow Morphology Database (LAMDA) was proposed as a GIS based central clearinghouse for remote and field investigations of volcanic morphology. This study presents an analysis of LAMDA’S...
Social-ecological resilience theory is part of a new paradigm for understanding and managing complex coupled human-ecological systems. The theory aims to inform explorations of a system’s ability to withstand disturbance while maintaining its critical functions. Adaptive co-management has been proposed as a governance mechanism that can enhance resiliency by combining...
New analyses of teleseismic body waves from moderate earthquakes in western Argentina demonstrate that active shortening of the Andean foreland occurs on reverse faults extending to 40–50 km depth. Existing crustal‐scale models of foreland deformation invoke thin‐skinned fault geometries, which root into an east‐dipping mid‐crustal décollement. Whereas thin‐skinned thrust sheets...
This thesis develops a manual for interpreters at six National Park Service areas established to preserve and interpret fossils of the Cenozoic Era: Fossil Butte National Monument (Wyoming), John Day Fossil Beds National Monument (Oregon), Badlands National Park (South Dakota), Florissant Fossil Beds National Monument (Colorado), Agate Fossil Beds National...
Nonindigenous species are a major threat to the ecological integrity and biodiversity of marine and estuarine ecosystems. To become a successful invader, species must pass through four phases: (1) survive transport, (2) survive release, (3) establish a population, and (4) expand their range. To better understand these processes, an integrated...