Research about Baker County, 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.

Oregon↗

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↗