Geoscience Colloquium: Carbonate Magmas, Plate Collisions and "Vitamins for the Industry"

Geological Association of Canada Hutchinson Lecture

Carbonatites are igneous rocks of mantle provenance that show remarkable enrichment in industrially important minerals that concentrate rare earths, niobium and other rare metals. The great practical significance of these rocks is grossly disproportionate to the small volume and punctuated distribution of carbonatitic magmatism through time. The current understanding of carbonatite petrogenesis has been strongly influenced by large-scale scientific and mineral exploration in areas of anorogenic alkaline magmatism (e.g., East African Rift, central and northern Europe). Historically, carbonatite occurrences in orogenic settings were not studied in as much detail or, in some cases, were simply overlooked owing to their superficial similarity to metacarbonate rocks. The renewed interest in rare-metal resources owing to the rapid development and implementation of innovative and green technologies in the past decade has provided an impetus for critical rethinking of some of the “  textbook” carbonatite wisdom, whereas the recent discoveries in Manitoba and elsewhere in the world have provided a framework and testing ground for the development of new ideas on the origin and evolution of these rocks. The major objectives of my research are to provide further insight into the place of carbonatites in continental magmatism, their role in metasomatic modification of mantle and crustal rocks, and their contribution to the evolution of alkaline silicate magmas commonly found in the same geological environment. An improved understanding of these key tectonic, petrologic and geochemical constraints on the formation of economic rare-metal mineralization is essential for the refinement of the existing exploration practices.