Landsliding is a significant contributor to continuous erosion
of the 150-mile northern Oregon coast. Direct loss of land to the sea
by landslides occurs along 47 percent of the coast. The remaining 53
percent has minor shifting of sand along depositional areas such as
spits and dunes. These minor movements...
Five lithologic units, ranging in age from Middle Miocene to Recent,
are defined on the basis of continuous seismic reflection profile records.
Two of the units are Miocene sedimentary and volcanic rocks that have been
truncated to form a major unconformity (post-orogenic surface) related to
the most recent major tectonism...
The continental terrace west of Oregon between 43° 50'N and
44° 40' N latitude is 50 to 55 miles wide. It consists of a continental
shelf, 16 to 35 miles wide, and a continental slope, 16 to 37 miles
wide. The eastern portion of the shelf is a smooth, sediment...
Sediments on the inner portion of the Oregon continental shelf
consist of clean, well-sorted, detrital sand. This sand has an average
median diameter of 2.53Φ (. 173 mm) and is both positively and
negatively skewed. Deposits with median diameters in the coarse
sand and gravel classes occur at depths of...
Three realms of deposition, Marine, Fluviatile, and Marine-
Fluviatile, are recognized in Yaquina Bay, Oregon, on the basis of
sediment texture and mineralogy. The Marine Realm extends 1.5
miles into the entrance of the estuary and is typified by normal
marine salinity and vigorous tidal action. Sediments of this realm...