The southern half of the upper Nehalem River basin contains
the most complete section of lower to middle Tertiary marine sedimentary
and volcanic rocks in northern Oregon. Determination of
stratigraphic relationships of six formations, and their depositional
environments and provenance is the chief objective of this paper.
More than 75...
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...
An investigation was conducted to determine the origin of
Mima mounds in Jackson County, Oregon and Thurston County,
Washington. Data on soil morphology, mineralogy, and particle
size distribution were used to test the periglacial ice wedge hypothesis,
the gopher hypothesis, the erosional hypothesis, and the
loess hypothesis.
The results of...
Late Quaternary sediments in the Willamette Valley, Oregon, include a unit of chiefly silt and fine sand, the Willamette Silt Formation. Previous workers have (1) Assigned the Willamette Silt different ages which range from Sangamon interglacial to late Wisconsin glacial, (2) Proposed that the Willamette Silt was deposited in a...
Anecdotal evidence suggests many Pacific Northwest estuaries are filling with sediment due to historical logging activities in upstream watersheds. Using the Siletz River estuary as a case study, this research began by analyzing timber harvest and discharge records of the Siletz River watershed, and found that increased timber harvest coincides...
The goal of this study was to advance methods for assessment of forest road hydrologic
response and sediment yield at a catchment scale. This research looked at the effect of
soil depth estimation on the Distributive Hydrology Soil Vegetation Model (DHSVM),
assessed the uncertainty and accuracy of hydrologic modeling of...
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Road Hydrology, Turbidity, and Suspended Sediment Measurements for Oak Creek,
Oregon
The Willamette Silt is a surficial geologic unit composed of successive Missoula Flood Deposits that underlies 3100 km2 (1200 mil) of arable land in the Willamette Valley of Oregon. The Willamette Silt protects the underlying regionally important Willamette
Aquifer from agricultural contamination while acting as a semi-confining unit and a...
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...
Shear wave attenuation measurements were made
using ceramic bimorph transducers to excite transverse
vibrations in a cylindrical column of unconsolidated
sediment. Three different water-saturated
sediments were used in an attempt to determine the
effects of grain shape and sorting on the frequency
dependence of attenuation. The mean grain size of...
Since the early 1950's, the distribution of sediment at the
mouth of Redwood Creek has been altered by the effects of channel
aggradation and channelization along the lower reach. Severe flooding
in 1953, 1955, and 1964 caused bank erosion, landsliding, and
channel geometry changes along Redwood Creek. The increased sediment...
The Cocos Gap is a deeper portion, or saddle, of the Cocos
Ridge and forms part of the western boundary of the Panama Basing
It is probably typical of saddles within most submarine ridges, In
order to determine the mechanisms controlling sediment dispersal,
the nature and sources of the sediments...
The conventional advection-dispersion equation cannot adequately describe all processes driving
solute transport in heterogeneous systems. This dissertation focuses on the individual influences
of both chemical (Chapter 2) and physical processes (Chapters 3 and 4) which affect
solute transport. In Chapter 2 we analyzed uranium transport in natural sediment using the...
Stratigraphy and chronology are essential to sedimentological study of Earth system histories. And, stratigraphy and chronology are often challenging and interesting problems themselves. The Quaternary (2.588 Ma - present) experienced paleoenvironmental and paleo-geomagnetic variability well outside the range of the recent instrumental record, providing the opportunity to place recent observations...