[PDF] Niobium and tantalum | Semantic Scholar
Comparison of Supercontinent Cycles in the Metallogeny of Niobium. A. Tkachev D. Rundqvist N. Vishnevskaya. Geology. Geology of Ore Deposits. 2020. Abstract The distributions of niobium mineral deposits and their resources on the geological time scale are analyzed. The sampling list includes 45 mineral deposits with their individual …