Uranium exploration in Paipa and Iza area (Colombia), new contributions (Preliminary report)

Full text: This paper shows the preliminary results from uranium exploration of the Boyaca Department, for the first survey conducted by the Colombian state after 26 years. The exploration is carried out this year and the zone covers an area of 460 square kilometers divided into three sectors, determinate from an analysis and appreciation of literature and field; these sectors are located in the municipalities of Sogamoso Paipa, Iza, Tota and Pesca, Chivata and Tuta. In the area is dominated by sedimentary rock since the Cretaceous age to tertiary and sediments of the Quaternary. In Paipa, and Isa outcrops volcanic and sedimentary rocks; the major structural features are Arcabuco anticline, Los Medios syncline and Boyaca and Soapaga faults. The sedimentary formations from the oldest to most recent in the area are: Tibasosa Formation; Une Formation, Conejo Formation; Plaeners Formation; Los Pinos Formation; Labor y Tierna Formation, Guaduas Formation Socha Formation; Picacho Formation an Concentration Formation; in the area outcrops also, volcanic rocks (riolites porphyrites and andesites); and explosive (pumices). In the Paipa Area, was found three anomalous sites (Durazno, Quebrada Honda and Casa Blanca) with values ranging between 440 and 7 500 aps the highest values was reported in the Durazno area. The outcrops are found in volcanic rocks (tophus) and tectonic breccias in the presence of thin strips of coal from the Guaduas Formation present there. In the year 1979 in studies by ENUSA (Spain) the highest values were reported from 3 800 aps. In Iza, was found five anomalous zones (El Crucero, San Miguel, Cuitiva - Iza, Erika and Tota - Pesca) with values ranging between 480 and 4 480 aps; outcrops in igneous rocks in Erika sector; and the highest values in phosphates was found in El Crucero sector with a maximum value of 2 100 aps. In holes made in Iza the values fell from 1 200 aps in surface to 4 480 aps in depth (1.60 m). In Paipa, we have values from 4 500 in surface to 7 500 aps at 1.50 meters, so that next year (2009), we will have some drills in Paipa as Iza in order to learn more about their behavior in depth and geometry of the potential deposits. (author)