The Clarno Formation is a series of volcanic, volcaniclastic, and related intrusive rocks located in central Oregon. It is the westernmost extent of a broader Eocene magmatic belt that covers much the western United States. The magmatic belt stretches eastward from Oregon to western South Dakota, and from the Canadian...
Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work evaluates the evolution of Cascadia mantle sources by documenting the isotopic and compositional characteristics of primitive basalts along a transect across the Eocene-Oligocene...
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...
Nine west-northwest-trending faults on the continental margin of
Oregon and Washington, between 43° 05'N and 470 20'N latitude, have been
mapped using seismic reflection, sidescan sonar, submersibles, and swath
bathymetry. Five of these oblique faults are found on both the Juan de Fuca
and North American plates, and offset abyssal...
This study illustrates geoarchaeological and paleoenvironmental approaches to the
investigation of an active margin coastal setting and provides examples of how information gleaned through examination of the stratigraphic record can reveal depositional signatures that provide insights into the geomorphic and tectonic forces active within coastal river basins. Three case studies...
The overarching objective of this study is to examine and compare the vulnerabilities of bridges combining effects of earthquake-induced ground shaking, ground failure (e.g., landslides and lateral spreading), and tsunami inundation. A parametric study is performed to understand the sensitivity of economic loss and traffic capacity with respect to the...