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Lead-alpha activity age determinations were made on zircon from seven granitic rocks of central and southeastern Alaska. The results of the age determinations indicate two periods of igneous intrusion, one about 95 million years ago, during the Cretaceous period, and another about 53 million years ago, during the early part...

Reconnaissance for uranium in Alaska during 1955 included airborne radiometric traverses, examination of radioactivity anomalies found during the airborne traverses, examination of prospector leads, and examination of areas that seems geologically favorable for the occurrence of uranium. The airborne radiometric traverses in central Alaska revealed 33 anomalies considered worth examining....

Field work leading to this report was done by the U.S. Geological Survey for the Division of Raw Materials of the U.S. Atomic Energy Commission. Nearly 24 townships were mapped in the central part of the Great Divide Basin, Sweetwater County, Wyoming. Fourteen of these townships contain outcrops of uranium-bearing...

The Midnite mine is on the Spokane Indian Reservation, Stevens County, Wash. Geologic mapping and reconnaissance in the vicinity of the mine indicate metasedimentary rocks of probable Precambrian age have been intruded by two varieties of quartz monzonite of probable Cretaceous age. Porphyritic quartz monzonite underlies about three-fourths of the...

In the Colorado Plateau uranium has been produced chiefly from very shallow mines in carnotite ores (oxidized vanadiferous uranium ores) until recent deeper mining penetrated black unoxidized ores in water-saturated rocks and extensive exploration has discovered many deposits of low to nonvanadiferous ores. The uranium ores include a wide...

Duttonite, a new quadrivalent vanadium oxide from the Peanut mine, Montrose County, Colo., has the formula VO(OH)2. The mineral occurs as crusts and coatings of pale-brown transparent platy crystals, as one of the first oxidation products of montroseite ore. It is associated with melanovanadite and abundant crystals of hexagonal...

No abstract available....

Uranium occurs as U(VI) and U(IV) in minerals of the Colorado Plateau ores. The number of species containing U(VI) is large, but only two U(IV) minerals are known from the Plateau: uraninite, and oxide, and coffinite, a hydroxy-silicate. These oxidize to yield U(VI) before reacting significantly with other...

A rapid-scanning microphotometer is described with which a 10-inch spectrum may be scanned in two minutes. The resulting chart may be 60, 300, or 1,500 cm long (wavelength scale) and 4 cm high (intensity scale). Commercially available components are used....