GRAPHITE-BEARING PELITIC SCHISTS AND THEIR ALTERED EQUIVALENTS IN THE DUFFERIN LAKE ZONE, SOUTH-CENTRAL ATHABASCA BASIN, SASKATCHEWAN: CONSTRAINTS ON GRAPHITE FORMATION AND DESTRUCTION, AND IMPLICATIONS FOR URANIUM MINERALIZATION

摘要

Unconformity-type uranium deposits from the Athabasca Basin area are considered to be the result of mixing between oxidized basinal brines and basement-derived reduced fluids/gases, and/or reduced basement rocks. Graphite and its breakdown products are suggested to be responsible for uranium mineralization by acting as a reductant that could trigger deposition of uranium. In addition, the presence of well-connected graphite and sulfides within graphitic pelitic rocks is considered to be potentially indicative of basement structures, as the minerals are often concentrated along the structures, which hence become electromagnetic (EM) conductors. Thus, exploration for uranium deposits is often focused on the search for EM conductors.