Lucius Pitkin, Inc.

The Tertiary sedimentary rocks in the lower Spokane River valley and in northern Spokane county, northeastern Washington, were investigated to determine the favorability for potential Ur resources.This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, chem. and mineralogical analyses of samples, and examination of available water well lithol. logs.An area of very high favorability is in the Spokane Indian Reservation along the lower Spokane River valley.It is an area which contains visible U minerals, but from which there has also been U productionAreas of medium favorability are the Harker Canyon area in the lower Spokane River valley and a portion of northern Spokane County.The Harker canyon area is underlain by rocks which are stratigraphically and structurally similar to, and probably an extension of, the very highly favorable rocks in the Spokane Indian Reservation.The Latah Formation in northern Spokane County is judged to have medium favorability based on the occurrence of thick sandstones derived partially from a quartz monzonite provenance and which reportedly contain organic material and volcanic derivatives

Gamma-ray spectrometric analyses for U, Th, and K and semiquant. emission spectrog. analyses were obtained on ∼500 samples collected from throughout the western USA.The regional variations of U, Th, and K concentrations in plutonic rocks were investigated on the basis of average values for one-degree latitude quadrilaterals and average values and frequency distributionsfor geol. subdivisions.The results indicate a general decrease in the concentrations of the 3 elements from the continental interior to the continental margin.Of the various chem. elements and indices considered the best possible indicators for U vein-type deposits are the Nockolds-Allen index, K, Si, the Fe3+-total Fe ratio, and the U-K ratio.Results indicate that plutonic bodies associated with known vein-type U deposits are characterized by unique geochem. abundances and relations and that the determination of geochem. guides and favorable areas for vein-type U deposits is possible.

The mineralogy and petrol. of the Schwartzwalder Mine ore is described, with emphasis on determination of paragenetic relation between individual minerals, groups of minerals, and entire rock units.Also, several factors discussed in previous studies were reevaluated inlight of a fresh approach to the vein mineral paragenesis, increased development of the mine, and extensive x-ray diffraction, S isotope, and linear regression anal.These factors include: the age of ore deposition; the form and source of the deposit; effects of the host rocks on ore deposition; geochem. mechanism for ore deposition; the type and extent of wall rock alteration; number of brecciation periods; the identity of the primary Mo mineral; the existenceof a black pyrite; and the relation of radiometric to chem. U3O8 values.