Kerogen and uranium resources in the Cambrian alum shales of the Billingen-Falbygden and Naerke areas, Sweden

The Cambrian alum shales contain Sweden's major reserve of fossil energy and Europe's largest low-grade source of uranium. The most uraniferous shales occur in the Billingen-Falbygden area of Vaestergoetland. The most kerogen and oil-rich shales occur in Naerke. Elsewhere the resources are vast but the concentration of these components are somewhat lower. In the Billingen-Falbygden area the most uraniferous shales occur within an area of ca 490 km2. They vary in thickness from 2.0-4.5 m, and contain 240-365 ppm U; they average ca 290 ppm U, ca 15.5 percent C sub (org) and ca 18 percent kerogen. In-ground resources of uranium in this unit alone are estimated to ca 1 million tonnes. In the Naerke area, the shales are composed of two members. The Upper Member contains an average of 175 ppm U, with the Oil Shale averaging 135 ppm U and the Uraniferous Shale 210 ppm U. The most uranium-rich part of the latter is ca 4.5 m thick and averages ca 245 ppm U. The Upper Member composes the fossil energy reserve. The Oil Shale and Uniferous Shale units together are up to ca 18 m thick and contain 18-22 percent kerogen; they occur in an area of ca 80 km2 and contain 350 million tonnes of kerogen. (Authors)