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Research about California, Oregon

Source-linked reports with geographic coverage including California, Oregon.

At least 127 records · Page 7Linked to original sources
USGS1986

Tectonic evolution of Northwest California and Southwest Oregon

Tectonostratigraphic terrances in northwest California and southwest Oregon record a complex history of subduction, collision, and transform faulting. During the late Jurassic Nevadan orogeny, the Elder Creek-Snow Camp and western Klamath terranes were imbricated during collision of an island-arc system with the continental margin. Subsequent collisions are recorded in the Pickett Peak (Early Cretaceous) and Yolla Bolly (middle Cretaceous) terranes.

California, Oregon↗
USGS1985

Map showing geochemical characteristics of the North Fork Smith River Roadless Areas, Del Norte County, California, Curry and Josephine Counties, Oregon

The North Fork Smith River Roadless Areas are located primarily in Del Norte County, northern California, include small parts of Curry and Josephine Counties, Oreg., and cover parts of the Gasquet, Crescent City, and Chetco Peak 15-minute quadrangles. The areas encompass aproximately 39,400 acres of Six rivers National Forest and 950 acres of Siskiyou National Forest and extend from just north of the California-Oregon border southward about 6 mi to the town of Gasquet, Calif. (fig. 1).

California, Oregon↗
USGS1983

Map showing characteristics of lode gold in the Medford 1 degree by 2 degrees Quadrangle, Oregon-California

About 500 lode gold occurrences, prospects, and mines have been reported from the Medford 1 o x 2 o quadrangle, Oregon-California. Summary descriptions of individual lode gold deposits and districts which include those occurrences in the Medford 1 o x 2 o quadrangle have been published by Brooks and Ramp (1968) and Hotz (1971) and by others cited in the reference lists in these two publications. As part of the Medford CUSMAP project between 1974 and 1980, some of these deposits were examined in the field during geologic mapping and geochemical sampling and most of the available information on individual deposits was compiled into a CRIB computer file (Computerized Resource Information Bank). This report is a summary of the more pertinent geologic and economic characteristics of the lode gold deposits for use in the resource evaluation part of the Medford CUSMAP project. The significant features described include the distribution of deposits and their relation to gross geologic and lithologic features, production information, mineralogy of the ore and gangue, gold-silver ratios, and speculations on possible genetic models for some types of deposits.

California, Oregon↗
USGS1983

Conodonts of the western Paleozoic and Triassic belt, Klamath Mountains, California and Oregon

Conodonts were extracted from 32 samples of limestone and 5 samples of chert obtained from the Western Paleozoic and Triassic belt of the Klamath Mountains province. Triassic conodonts were found in 17 samples, and late Paleozoic conodonts in 7 samples. Conodonts of the remaining 13 samples cannot be dated more closely than early or middle Paleozoic through Triassic. The late Paleozoic conodonts are restricted to the North Fork and Hayfork terranes. The Hayfork terrane also contains Early, Middle, and Late Triassic conodonts; mostly Neogondolella. Conodonts from samples of the Rattlesnake Creek terrane and the northern undivided part of the belt are all Late Triassic and are generally Epigondolella. The conodont data support the concept that many of the limestone bodies are olistoliths or tectonic blocks in melange. Color alteration of the conodonts indicates that the rocks of the Western Paleozoic and Triassic belt have been heated to temperatures between 300 degrees and 500 degrees C during regional tectonism.

California, Oregon↗
USGS1982

Map showing sampled radiolarian localities in the western Paleozoic and Triassic belt, Klamath Mountains, California

The western Paleozoic and Triassic belt, the largest of several major subdivisions of the Klamath Mountains geologic province, extends 300 km northward from the south end of the province in California to the north end of the province in Oregon (see inset map). The rocks of the belt are mainly sedimentary and volcanic, including tuff, cherty tuff, chert, argillite, limestone, and volcanic flows and breccia. They are of oceanic and island arc facies and are highly disarranged tectonically. The southern part of the belt is subdivided into three tectonostratigraphic terranes --- the North Fork, Hayfork, and Rattlesnake Creek terranes. The central and northern parts of the belt are undevided.

California, Oregon↗
USGS1982

Water-quality assessment of the Smith River drainage basin, California and Oregon

A water-quality assessment of the Smith River drainage basin was made to provide a summary of the water-quality conditions including known or potential water-quality problems. Results of the study showed that the water quality of the Smith River is excellent and generally meets the water-quality objectives for the beneficial uses identified by the California Regional Water Quality Control Board, North Coast Region. Known and potential problems related to water quality include: Sedimentation resulting from both natural erosional processes and land-use activities such as timber harvest, road construction, and mining that accelerate the erosional processes; bacterial contamination of surface and ground waters from inundated septic tanks and drainfields, and grazing activities; industrial spills which have resulted in fish kills and oil residues; high concentrations of iron in ground water; log and debris jams creating fish migration barriers; and pesticide and trace-element contamination from timber-harvest and mining activities, respectively. Future studies are needed to establish: (1) a sustained long-term monitoring program to provide a broad coverage of water-quality conditions in order to define long-term water-quality trends; and (2) interpretive studies to determine the source of known and potential water-quality problems.

California, Oregon↗
USGS1973

Sr87/Sr86, K, Na, Rb, and Sr in some eclogites and associated basalts from California and southwestern Oregon

Six samples of group C eclogites from California and southwestern Oregon have initial Sr 87 /Sr 86 ratios in the range of 0.7028 to 0.7051; Rb contents from less than 1 to 53.4 ppm; and Sr contents from 147 to 270 ppm. These data and major-element compositions suggest that the eclogites were derived from basalts older than but similar in composition to those intercalated with Mesozoic cugeosynclinal sedimentary rocks in California and western Oregon. The isotopic heterogeneity of the eclogites and associated graywackes contrasts with a uniformity of Sr 87 /Sr 86 in many younger calc-alkaline volcanic rocks of the circum-Pacific province. Derivation of the younger volcanic rocks from an eclogite-blueschist melange isotopically similar to those investigated here would require isotopic homogenization or integrated partial melting over sufficient volumes so as to reduce these variations in the derived melts.

California, Oregon↗