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

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

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.

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.