The middle to upper Eocene Tillamook Volcanics form the basement in the Rock Creek - Rocky Point area. These tholeiitic to alkalic basalts, basaltic andesites, and andesites were erupted as shield volcanoes seaward of the strandline ontop of an older deep-marine mudstone unit (Yamhill Formation) and an accreted portion of...
The area studied in detail, known as the Antone District,
is located in the southeast corner of Wheeler County, Oregon, ,
between longitude 119 37. and 119°54 east, and latitude 44°23
and 44°3O' north.
Surface elevations range from 3050 feet above sea level in
the northeast corner of the district,...
Clatsop Beaches, characterized by flat beach-face slope (1:70) and small sandsize (0.2 mm.), have supported commercial and recreational fisheries for the razor clam (Siliqua patula) for many years. Tracing the linear growth of two year classes through more than one year following set led to a validation of the ring...
The appropriate use of disaggregated economic data not only improves the accuracy and robustness of economic analyses, but also extends the existing economic models to address new aspects of the issue. This dissertation consists of three essays: two essays use disaggregated economic-engineering data to address spatial heterogeneity in economic losses...
The thesis area consists of 44 square miles in southeast Harney
County, Oregon. The Pueblo Mountains are located in the northwest
part of the Basin and Range structural province, and are characterized
by normal faults of large displacement that produced the tilted fault
block mountain range.
The oldest rocks exposed...
Six early to middle Tertiary geologic units crop out in the
Saddle and Humbug Mountain area. They include the late Eocene to
early Miocene Oswald West muds tones, the lower Silver Point and
the upper Silver Point tongues of the middle Miocene Astoria Formation,
and the middle Miocene Depoe Bay...
The Murderers Creek Area, within the Aldrich Mountain province of
northeast Oregon, originated in an arc-trench gap during Permian-early
Triassic time. The area represents a small portion of a forearc
depositional basin and tectonic highland which borders the basin along
its seaward margin. The trench associated with an east dipping...
Pre-Tertiary metamorphic rocks, Jurassic granitic intrusions,
and Eocene basalts are exposed along the North Fork of the John Day
River at its confluence with Granite Creek. Geochemical and textural
evidence suggest greenschist-metamorphosed, strongly sheared,
volcanogenic rocks originated in an island-arc environment. These
greenstones were apparently intruded during the Late Permian...
The type section of the Mascall Formation, which is located in
the John Day Valley, is interpreted to represent a sequence of
paleosols. These fossil soils were formed on a floodplain during the
middle Miocene. The measured thickness of this section is 1340 feet,
and although the top of the...
The upper Eocene to lower Oligocene Oswald West mudstone is
the oldest formation (informal) in the Green Mountain-Young's
River area. This 1,663 meter thick hemipelagic sequence was deposited
in a low-energy lower to upper slope environment in the Coast
Range forearc basin. The formation ranges from the late Narizian
to...
Castle Rocks is 12 miles east of Mt. Jefferson, in the central
Cascades of Oregon. The area contains volcanic rocks ranging from
mid-Miocene to Holocene in age. These rocks record alternating
periods of tholeiitic and calc-alkaline volcanism.
The oldest rocks in the area range from basaltic andesite lava
flows to...
The Coyote Hills are located about 46 kilometers north-northwest
of Lakeview, Oregon, within the Basin and Range physiographic province.
These hills represent a complex volcanic center of bimodal
calc-alkaline igneous activity.
The oldest rocks recorded in the Tertiary succession are horn-blende-
bearing andesite and aphanitic basalt flows, laharic breccias,
conglomerates,...
The purpose of this report is to present some information which has been collected on the razor clam fisheries of Clatsop County beaches during the past several years. Topics which will be discussed are: (1) a brief resume' of the investigation, regulations, and catches prior to September 1954; (2) regulation...
The thesis area is located in the southeastern corner of Harney County, Oregon. This portion of Oregon is situated in the northern part of the Basin and Range province, and is characterized by both mafic and silicic extrusives, and localized nonmarine sediments and
tuffs ranging in age from middle (?)...
Pluvial Lake Chewaucan was a late Pleistocene lake, as much as 375 feet deep, covering 480 square miles in the northwestern part of the Great Basin in southern Oregon. The lake basin, now occupied by Summer Lake, Upper and Lower Chewaucan Marshes, and Lake
Abert, was formed by down-dropped fault...
The California brown pelican (Pelecanus occidentalis californicus) is listed as an endangered species under the U.S. Endangered Species Act. The Recovery Plan for this subspecies outlines the need to "Assure long-term protection of adequate food supplies and essential. . .roosting. . . habitat throughout the range." I investigated the effects...
The Bear Creek area is situated at the boundry between the Basin and Range Province, Deschutes Basin and Blue Mountains Province. It contains rock units representing most of the Cenozoic geologic column. The major rock units exposed are the Clarno Formation, John Day Formation, Columbia River Basalt Group, Deschutes Formation...
New data are presented that provide evidence for the onset of extensional deformation in the Northwestern Basin and Range within 1 million years after the eruption of the Steens Basalt at 16.5 Ma. New geologic mapping (1:24,000), stratigraphic sections, and ⁴⁰Ar/³⁹Ar dating of the Crane Basin rocks provide a control...
Published January 1968. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published January 1947. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published February 1936. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published April 1956. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
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...
Snow Peak is a voluminous shield volcano located ~50 km west of the axis of
the modern Cascade arc. A previously published K-Ar age estimate indicates that the
Snow Peak lavas are ~3 Ma. Subsequently, the preliminary research framework for
studying the Snow Peak lavas focused on constraining the petrogenesis...
Eleven sedimentary and volcanic rock units are mapped and described in the thesis area, and chronicle the dynamic geologic history of the Tillamook embayment from the Oligocene through the middle Mlocene. The
oldest unit is the Zemorrian to early Saucesian Smuggler Cove formation, a bathyal tuffaceous mudstone with some thin-...
The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks were produced in an extensional tectonic setting in the developing forearc and formed an extensive tholeiltic oceanic island. The...
The middle to upper Eocene Tillamook Volcanics form the volcanic core or basement rocks in the Rock Creek-Green Mountain area. They consist of a thick sequence of high TiO2 tholeiitic basalt, basaltic andesite, and andesite subaerial flows and breccias. Detailed mapping, petrography, major oxide plots, magnetic polarity, and radiometric age...
Eight Tertiary geologic units crop out in the Seaside-Young's River Falls area, including late Oligocene to early Miocene Oswald West mudstones; Angora Peak sandstone and Silver Point members of the middle Miocene Astoria Formation, and middle Miocene Depoe Bay and Cape Foulweather Basalts. Three new lithologically distinct
units, the 'J'...
The middle Eocene Tillamook Volcanics form the oldest rock unit in the Elsie-lower Nehalem River area. K-Ar age determinations and age constraints imposed by foraminiferal and calcareous nannofossil assemblages of overlying sedimentary strata indicate an absolute age of about 42 Ma for the uppermost Tillamook Volcanics. Major oxide values indicate...
Six Tertiary units are exposed in the Onion Peak area near the town of Cannon Beach., Oregon. The units consist of: late Eocene to
early Miocene Oswald West mudstones (informal), middle Miocene Astoria Formation (Angora Peak sandstone and Silver Point mudstone members.-informal), middle Miocene basalts of intrusive and extrusive Depoe...
The thesis area is located in the Blue Mountains of northeast Oregon. Pre-Tertiary and Cenozoic rocks, divided on the basis of age and tectonic history, are exposed along the eroded crest of the Blue Mountain anticline. Permian (?) metasedimentary rocks probably correlate with the Elkhorn Ridge Argillite, and consist mainly...
The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom and molluscan fossil identifications, with subsurface geophysical data and petrographic and geochemical analyses. The stratigraphy of the study area consists of two...
Six Tertiary rock units are exposed in the Bear Creek-Wickiup Mountain-Big Creek area. They are: the late Oligocene to early Miocene Oswald West mudstones; the Big Creek sandstone member, the Pipeline member (a new unit), and the Silver Point mudstone member of the early to middle Miocene Astoria Formation; and...
Four distinct lithologic units compose the Tertiary rocks of the Neahkahnie Mountain - Angora Peak area, located along the northwest
Oregon coast near the town of Nehalem. The Tertiary units are the late Oligocene to early Miocene Oswald West mudstones, the middle Miocene Angora Peak sandstone member of the Astoria...
Five early to middle Tertiary bedrock geologic units crop out in the study area. These include the late Eocene to early Miocene Oswald West mudstones; the Tucker Creek sandstone, Big Creek sandstone, Silver Point mudstone, and Pipeline members of the
early to middle Miocene Astoria Formation; and the middle Miocene...
Five distinct lithologic units compose the Tertiary rocks in the Tillamook Head - Necanicum Junction area of the northern Oregon Coast Range. They are: the late Eocene to early Miocene Oswald West mudstones, the middle Miocene Angora Peak sandstone and
Silver Point mudstone members of the Astoria Formation, and the...
Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt,...
Twelve rock units, from upper Eocene to middle Miocene are exposed in the Nicolai Mountain-Gnat Creek area. They are, from oldest to youngest: Pittsburg Bluff Formation; Oswald West mudstone; Big Creek sandstone, upper Silver Point mudstone, and
Pipeline mudstone members of the Astoria Formation; Depoe Bay Basalt; Grande Ronde Basalt;...
The late Oligocene Yaquina Formation is exposed in an arcuate outcrop pattern which extends along the central Oregon Coast from
Siletz Bay on the north to Seal Rock on the south. Maximum inland extent of the Yaquina outcrop is :five miles. Maximum thickness of the Yaquina Formation is 2, 000...
The Tumalo quadrangle lies approximately 30 kilometers behind the Cascade volcanic arc and marks the southernmost extent of continuously exposed Deschutes Formation rocks. Deschutes Formation rocks in the
Tumalo quadrangle include late Miocene volcaniclastic sedimentary rocks, ignimbrites and lapillistones, and late Miocene to early
Pliocene basalts and basaltic andesites. Volcaniclastic...
The Whitewater River area is located directly east of Mt. Jefferson in the Cascades of central Oregon. Approximately 90 mi2 (230 km2) were mapped (scale 1/24,000) and four new K-Ar ages and 151 major element analyses were obtained in a study of the stratigraphic
and magmatic transition from the Miocene...
The Mitchell inlier in north-central Oregon contains the largest exposure of Cretaceous marine sedimentary rocks in this region. Nearly 9,000 ft of Albian-Cenamanian rocks are exposed along the flanks of the Mitchell anticline. The Cretaceous section rests unconformably overlain by Tertiary volcanic rocks. The Cretaceous rocks have previously been divided...
The mapped area is part of the middle Deschutes Basin of central Oregon, which lies in the northwestern corner of the High Lava Plains physiographic province, between the Cascade and Ochoco Mountains. It is underlain by Cenozoic lavas, tuffs and sediments of continental origin. The oldest rocks in the sequence...
A thick sequence of intercalated andesite and basalt flows, tuffs, and volcanic sediments crop out in the Fly Creek Quadrangle and the north half of the Round Butte Dam Quadrangle. This sequence was deposited in the ancestral Deschutes River Valley along the east flank of the Cascade Range during the...
A study conducted along the Lincoln County, Oregon coast delineated the exact location of 153 landslides. The landslides were found through the interpretation of aerial photographs. Each landslide was verified in the field and its class (ancient, historic, recent), type (slump, debris slide or flow, planar slide),, and status (stable,...
This report presents data collected during the first full field season of
a project designed to examine the streamflow requirements of juvenile salmonids. Problems encountered in the original design, changes made in the design and the application of the expected results are discussed.
About 300 local businesses and industries in Clatsop County were interviewed and asked questions about their sales and purchases. The information they supplied from this survey was used to develop the economic model. This publication describes some of the findings of the study and how the model can be used...
(1) Field mapping and biostratigraphic data indicate that the Yamhill Formation overlies and is younger than the Tyee Formation; interfingering of the two formations is not indicated. (2) Stewart's correlation of the Yamhill Formation with the Sacchi Beach member of the Tyee was based on incomplete knowledge of the range...
Our studies and those of our colleagues in Idaho indicate that the western Snake River Basin is a major geothermal province, similar in some ways to the Imperial Valley Geothermal Province. Deep drilling should encounter high temperature fluids in permeable rocks below 2 km and at shallower depths where permeability...
The stacks off the southern Oregon coast have been studied very little because of difficulties of access (see, for example, Weissenborn and Snavely, 1968). Work described herein was helicopter-supported; skillful piloting by Earl Lady permitted landings on or close approaches to many stacks. To help delineate the structure, field work...
The Oregon coast between Yaquina Head and Government Point owes its scenic grandeur to a unique wedding of ancient and recent marine environments. Visitors to Beverly Beach State Park, located in the southern part of this coastal strip, have a rare opportunity to wander along a shoreline that some 15...
This field trip consists of two geologic tours. On Tour 1, the Tertiary sedimentary rocks exposed along the Yaquina River between Newport and Toledo, Oregon, will be examined. This tour will start at the mouth of Yaquina Bay where Miocene sedimentary rocks are exposed and will proceed generally eastward and...