Geology topics

Research about Baker County, Oregon

Source-linked reports with geographic coverage including Baker County, Oregon.

4 recordsLinked to original sources

USGS1980

Chemistry of zeolites and zeolitic tuffs from a Pliocene lacustrine deposit near Durkee, Baker County, Oregon

Zeolites in an unnamed Pliocene lacustrine and fluviatile deposit near Durkee were first mentioned by Eakle (1898). He described a new zeolite, erionite, from a small opal quarry in a "rhyolite" (welded ash-flow tuff) about 6 km southeast of Durkee. Eakle, unfortunately, provided only a vague description of the type locality of erionite; and more than half a century passed before the type locality was rediscovered by L. W. Staples, and additional specimens were compared with Eakle's original material (Staples and Gard, 1959). Prior to the late 1950's, the Durkee locality was the only confirmed occurrence of erionite in the world. Our investigation of the zeolites and the diagenesis of tuffaceous rocks near Durkee began late in 1970 after a brief reconnaissance early in that year showed an abundance and variety of authigenic zeolites in silicic tuffs of the lacustrine deposit. Field studies continued intermittently until 1972, and laboratory studies continued intermittently until 1976. Preliminary findings have been published in two brief reports (Sheppard and Gude, 1975; Gude and Sheppard, 1978). This present report is concerned only with the chemistry of certain zeolitic tuffs from the Durkee deposit and with the chemistry of chabazite, clinoptilolite, and erionite that were separated from six of the tuffs.

Oregon↗

USGS1978

Chabazite in siliceous tuffs of a Pliocene lacustrine deposit near Durkee, Baker County, Oregon

A relatively pure chabazite deposit of at least 75 X 10 6 metric tons occurs near the Durkee type locality of erionite. This erionite is in a welded tuff interbedded with lacustrine rocks- of a closed Pliocene basin. The zeolites, chabazite, erionite, clinoptilolite, and other authigenic silicate minerals are confined to a 27-square-kilometer area of altered rocks enclosed in relatively freshwater lacustrine beds. About 135 meters of the lower part of the 350-m stratigraphic section at the southeastern part of the lake basin contain zeolitic tuff. The chabazite is an early product of the reaction between glass of rhyolitic or dacitic composition and alkaline (pH>9) saline lake waters. Erionite, clinoptilolite, analcime, and potassium feldspar follow chabazite in the paragenetic sequence. At the erionite type locality, chabazite and clinoptilolite form megascopic crystal clusters within fractures and cavities in unaltered welded tuff. Elsewhere in the basin, most zeolite crystals in the altered airfall or reworked tuffs are less than 80 micrometers long. Chemical analyses, unit-cell determinations, and mean indices of refraction show that fine-grained chabazite varies in composition and physical parameters.

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USGS1964

Ground-water reconnaissance in the Burnt River valley, Baker County, Oregon

The Burnt River valley in southern Baker County, Oreg., is underlain by rocks that range in age from pre-Tertiary to Quaternary. The pre-Tertiary rocks consist mainly of argillites, schists, limestones, and intrusive igneous rocks, while the Tertiary rocks consist mainly of felsic and mafic volcanic tuffs, lava flows and breccias, and fluviolacustrine deposits. Quaternary rocks include terrace gravels of Pleistocene and Recent age, and stream-valley alluvium of Recent age. The rock units most widely exposed along the valley are the fluviolacustrine deposits of Miocene and Pliocene(?) age, which extend to depths of as much as a thousand feet below the valley floor, and the pre-Tertiary rocks. Most of the rocks that underlie the valley are of relatively low permeability and yield only small to moderate quantities of water (generally less than 50 gpm) to wells. The fluviolacustrine deposits contain scattered lenses of relatively permeable sand and gravel, hut the unit as a whole is mainly silt and clay of low permeability. Two prospective irrigation wells in the area penetrated these deposits but were abandoned because of insufficient yield. Perhaps the most permeable rock unit in the area is the Columbia River Basalt of Miocene and Pliocene(?) age. It is exposed extensively west of the main valley, but apparently occurs only' as discontinuous lenses beneath the valley floor. Chemical analyses of water from seven wells in the area indicate that the ground waters have relatively large concentrations of dis-. solved mineral constituents. Water from two of the wells had excessive concentrations of boron and high sodium and salinity hazards with respect to use for irrigation. Perhaps the most favorable site for a test irrigation well is about 8 to 10 miles east of Hereford, where the Columbia River Basalt apparently extends beneath, and is intercalated with, the fluviolacustrine deposits.

Oregon↗

USGS1951

Ground-water resources of Baker Valley, Baker County, Oregon

The Baker Valley is the southern part of a small oval-shaped inter-montane structural basin located near tie southeastern edge of the Blue Mountains of northeastern Oregon. The Powder River enters and leaves the valley through narrow rock gorges. The alluviated basin floor at an altitude of about 3,400 feet is bounded by high, Alpine-type mountains on the west and by lover hilly ridges on the north, east, and south. Creeks descend across alluvial fans from the higher western margin of the valley to the Powder River on the valley floor. The valley floor and the contiguous alluvial slopes are formed of unconsolidated deposits of Quaternary age having a thickness of more than 700 feet in the central part of the valley. The surrounding higher lands are formed of consolidated rocks composed of volcanic flows, tuffs, and partly consolidated deposits of Tertiary age, and sedimentary, igneous, and metamorphic roots of late Paleozoic age. The unconsolidated materials underlying the alluvial slopes are mostly fanglomerates - composed of partly consolidated angular rock fragments imbedded in assorted finer materials - and fine-grained sedimentary deposits having much inter-bedded gravel and sand along the valley floor. The unconsolidated deposits contain a body of ground water, the upper surface of which is called the water table. The water table slopes down gradient approximately parallel to tile land surface. Variations in the general inclination of that water table indicate that drainage on different segments of the alluvial slope is influent and effluent to the ground water body. Yields from wells in the fanglomerate along the rest side of the valley are not large, but large yields are obtained from wells on the valley floor just north of Baker. Properly constructed test wells have not been drilled over much of the northern part of the valley floor. The Tertiary rocks of both volcanic and sedimentary origin along the margin of the valley east of Baker contain some ground water under sufficient pressure to cause wells to flow at the surface, but generally those strata are not highly productive. Some water occurring along fault lines in these rocks has all abnormally high temperature. The growing season in this area is short and the use of shallow water for irrigation may aid materially in securing the maximum returns of which the valley is capable.

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