Introduction: From the inception of the effort to utilize atomic energy Perú has been of interest as a possible source of radioactive raw materials because of its great variety and abundance of metals. Because of this and a desire at that time to develop additional supplies of uranium, a cooperative program to search for uranium deposits was initiated in 1953 by the Junta and the USAEC.

Discussing water samples collected during a reconnaissance study for uranium, and the analysis of the samples.

Discussing a general reconnaissance for uranium in the Aisen area of southern Chile.

Discussing Laboratory and field studies that show that the geologic history and environment of the Colimapu formation of central Chile differed considerably from those of the uranium-bearing Diamantiano formation of Argentina with which the Upper Colimapu has been correlated.

Discussing a two-week reconnaissance of the Lonquimay area, in south-central Chile, in which anomalies were noted in marl and in a sulfide-mineralized shear zone in continental black shales

Abstract: In 1957 uranium was discovered in the Vilcabamba district on the north flank of the Cordillera Vilcabamba, part of the Cordillera Oriental. This district contains principally small copper-nickel veins. Small lenses of uraninite occur in calcite veins cutting Permian Copacabana limestone. Uranium is most abundant marginal to centers of strongest copper-nickel mineralization. Leaching and oxidation are virtually absent because of Pleistocene glaciation. Four separate areas in which uranium has been identified are Huamanapi, Calderon, Minasmayo, and Negrillas. The Puntarayoc area, near Pampaconas, is considered a separate district. The deposits have been tested by trenching, drilling, and sampling concurrently with geologic reconnaissance mapping of the surrounding region.