Relationships of calcium carbonate to lithology and vanadium-uranium deposits in Salt Wash sandstone of southwestern Colorado

This study was made to determine whether any relationship exists between lithology or vanadium-uranium deposits and calcium carbonate content in the Salt Wash member of the Morrison formation of Jurassic age. Results indicate that altered gray-green mudstone contains less carbonate than does unaltered red-brown mudstone. No significant difference exists between the carbonate content of unaltered light red sandstone and altered light gray sandstone. Within the sandstone there are carbonate-rich zones adjacent to contacts with mudstone. Calcium carbonate content and ore grade are not related, although carbonate-rich zones parallel the ore bodies. These carbonate-rich zones may possibly be used as an ore guide. The present distribution of calcium carbonate could have resulted from early diagenesis with later redistribution during mineralization.