Based on the principle that the history of a discipline is important to the discipline itself, this thesis devotes two chapters to ROBERT HOOKE AND THE FOUNDATION OF GEOLOGY and two chapters to modern geology, viz. THE TECTONIC EVOLUTION OF THE OREGON CONTINENTAL MARGIN. The first part of this abstract...
Sea-cliff erosion is a significant problem along the Oregon coast in that many
communities have been built on terraces affected by bluff retreat. There is considerable
coast-wide variability in the rates of cliff erosion. This variability is attributed in part to
tectonic activity that is causing differential interseismic uplift along...
Tillamook Bay is the second largest estuary on the Oregon coast, and concerns have been raised whether human induced impacts have been responsible for the perceived increase in sedimentation rates during the past century. Major land-use practices within the five watersheds of the Bay include logging, forest fires, the construction...
Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. This study examines shoreline erosion in Flathead Lake, Montana due to five decades of artificially elevated lake levels. It provides a model to investigate coastal erosion associated with sea-level rise. The natural water...
Grain-size distributions of gravels transported as bedload in Oak Creek, Oregon,
show systematic variations with changing flow discharges. At low discharges the gravel
distributions are nearly symmetrical and Gaussian. As discharges increase, the
distributions become more skewed and follow the ideal Rosin distribution. The patterns of
variations are established by...
The formation of beach placers primarily involves processes of
waves and currents that selectively sort and concentrate the valuable
minerals according to their densities, sizes and shapes. Black sand
placers are found on the beaches adjacent to the mouth of the Columbia
River. Reviews of historical shoreline changes show that...
Straight, radial, erosional channels and fan-like deposits of tephra develop around steep-sided cones and composite volcanoes, but are not characteristic features of shield volcanoes. The channels and deposits normally are formed by explosive volcanic density currents which originate as nuées adrentes or base surges. The physical processes of explosive volcanic...