Spelling suggestions: "subject:"coasts -- oregon"" "subject:"coasts -- pregon""
11 |
Climate and heat exchange in the oceanic region adjacent to OregonLane, Robert Kenneth 20 April 1965 (has links)
The climate and the exchange of heat between atmosphere and
ocean are examined in a region adjacent to Washington and Oregon,
and in two sub-regions adjacent to Oregon. The sub-regions are
chosen such that one contains the nearshore upwelling region and the
other borders it on the seaward side.
The data (ship weather observations, 1953 to 1962) reveal the
general seasonal variation of climatic factors in the regions studied
and the effects of the nearshore upwelling of cold water on the climate
over the coastal ocean region and the adjacent coastal land mass. In
the nearshore sub-region, summer values of temperature (air, wet
bulb, and sea surface) are lower than those to seaward, but winter
values are higher inshore than to seaward. The effects of these differences,
and of other factors, on the heat exchange processes are
examined with the use of empirical equations. It is seen that the processes
of evaporation and conduction are suppressed considerably
and net long wave radiation is slightly suppressed in the upwelling
region during the summer.
The effects of the reduction of heat loss to the atmosphere in
the summer upwelling region on the climate of coastal Oregon are
seen to be a slight reduction of air temperatures and, despite reduced
evaporation, a very slight increase of relative humidity.
Monthly means of daily net heat exchange between the sea and
the atmosphere are examined and correlated with the difference between
monthly means of the heat used per day in the oceanic evaporation
process and the monthly means of daily totals of heat estimated to be
used in the evaporation from a shallow pan under climatic conditions
identical to those accompanying the net heat exchange and oceanic
evaporation. / Graduation date: 1965
|
12 |
Continental shelf sediments, Columbia River to Cape Blanco, OregonRunge, Erwin John 01 December 1965 (has links)
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 20 to 40 fathoms and
probably represent ancient beach or fluviatile deposits formed during
lower stands of sea level.
The outer shelf and upper slope are covered by poorly sorted
sediments with median diameters in the fine sand to fine silt classes.
Mean diameters of the sediments are almost always smaller than
their median diameters and the sediments are positively skewed.
The heavy mineral assemblages are dominated by the amphibole
and pyroxene groups and the opaque-garnet association.
Pyroxenes are most abundant in the coarser-grained sediments of the inner shelf and decrease in abundance offshore. Amphiboles are
most abundant in the finer-grained sediments of the outer shelf and
upper slope. Highest concentrations of the opaque-garnet association
also are found in the inshore samples.
Sediments of the continental shelf are derived from two principal
sources, rivers and erosion of coastal terrace deposits.
Rivers are probably contributing only fine-grained material to the
shelf as much of the coarser fluviatile material is thought to be
trapped in the estuaries. The terrace deposits are actively being
eroded and are thought to contribute about 21,000,000 cubic feet
(.00013 cubic miles) of sediment to the continental shelf annually.
Evidence suggests that much of the inner-shelf sand is probably
a relict transgressive sheet sand that was deposited during the
last rise in sea level. Most of the deposition of the modern sand on
the shelf has been confined to the inner portion of the inner shelf.
Finer-grained sediments have been deposited on the outer shelf and
upper slope.
Characteristics of the sediments on the present continental
shelves may be useful in identifying continental shelf deposits in
the geologic column. / Graduation date: 1966
|
13 |
Geology of the continental terrace off the central coast of OregonMaloney, Neil Joseph 23 April 1965 (has links)
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 covered
area that slopes very gently west. The western portion of the shelf
contains four rocky bank areas. The banks are topographically irregular
and appear to be of structural origin. West of the banks the
shelf edge occurs at depths of 71 to 90 fathoms.
The continental slope extends from the edge of the shelf to the
abyssal plain at depths of 1530 to 1610 fathoms. A smooth upper slope
of less than three degrees extending to depths of 117 to 250 fathoms
occurs north and south of Heceta Bank. West of Heceta Bank the upper
slope is formed by a scarp that slopes 10° to 16° to 560 to 725
fathoms. West of the upper slope there is an area of irregular topography,
including benches, hills and scarps, which extends to depths
of 380 to 1100 fathoms. The lower part of the slope is formed by a
north-striking scarp which is 3000 to 6000 feet high and slopes 04° to
15°. The bathymetry indicates that the continental slope was formed
by step-type, block faulting.
Sediments form a thin surface layer over much of: the terrace.
Detrital sand, similar to the coastal sand, covers the shelf from the
shoreline to approximately 50 fathoms. The deeper areas on the shelf
and upper part of the slope are covered by glauconitic sands and silts
on the topographic highs and olive green, clayey silts in the topographic
lows. The intermediate and lower portions of the slope are
blanketed with olive-green, clayey silt. In these sediments the sand
fraction, which generally comprises less than five percent of the sample,
is composed chiefly of diatoms, Foraminifera, Radiolaria, and
sponge spicules. Sands are also present on the intermediate and deep
portions of the slope. Dredge hauls west of Newport obtained sand
composed mainly of detrital grains which may have been derived from
an underlying friable sandstone. Thin layers of sand occur in cores
from other portions of the slope. These sands may have been derived
by down slope movement of sediment from the upper slope and the
shelf.
Sedimentary rocks of Upper Miocene and Pliocene age crop out
on the shelf banks and on the continental slope. The banks consist of
a sequence of diatomaceous, clayey siltstones with interbeds and
concretions of calcareous siltstones. Glauconite sandstone, gray
wacke sandstone, and limestone breccia are exposed along with the
siltstone, on the northern end of Heceta Bank. Most of the rocks obtamed
from the slope are similar to those from the shelf. Friable,
wacke sandstone is exposed on the slope west of Newport.
Foraminifera, the sand fraction compositions, and textural analyses
all indicate that the sediment forming the siltstones from the
shelf were deposited at lower littoral to lower bathyal depths.
The sediments forming the rocks were deposited in one or more
sedimentary basins during the Miocene and Pliocene. The subsidence
continued until the. Late Pliocene when the area began to rise. The
area was uplifted as much as 1000 fathoms by the Late Pleistocene
when the shelf was eroded by transgressions and regressions resulting
from sea level changes. The last rise in sea level resulted in the erosion
of the shelf to its present form and the deposition of a thin layer
of sediment. Sand is presently being deposited on the shallow areas
adjacent to the continent, and silt and clay are being laid down on the
slope and the sheltered areas of the outer shelf. / Graduation date: 1965
|
Page generated in 0.0483 seconds