Halos of hematitization generally occur in the peripheral, more dense areas surrounding impregnated pitchblende ores, in rocks surrounding veinlets of pitchblende and in the gouge of these veinlets. The breadth of the reddening halo in the rocks can range from fractions of a millimeter to tens of meters. Developing at the edges of oxides and silicates of uranium (IV) and forming the outermost zone, hematite and goethite are present as finely dispersed particles impregnating grains of feldspar and sometimes quartz, chalcedony, calcite and replacing ferrous iron minerals such as chlorite, ankerite, siderite, biotite, pyrite, magnetite and ilmenite. In the immediate vicinity of the ore veins and phenocrysts of pitchblende, an additional quantity of modal iron is often found as oxide, indicating that this element has been carried in and precipitated as a result of oxidation or alkalization of hydrothermal solutions. 15 references, 1 figure.

V. M. Rekharskaya

Papers

The radiogenic hypothesis of formation of periore zones of hematitization in hydrothermal uranium deposits