stub - March 2023
“Ultramafic rocks are a vast family of rocks consisting predominantly of mafic minerals (olivine, pyroxene, and amphibole) with very limited contents of felsic minerals (generally calcium plagioclase) and other accessories (garnet, spinel, phlogopite, etc.). These rocks comprise peridotites, constituting the Earth’s mantle, and various ultramafic cumulates that form by segregation of mafic minerals within peridotites or by settling at the base of magma chambers, generally of gabbroid rocks.” - Classification of ultramafic rocks – Geology is the Way
Ultramafic rocks are also often termed as ultra-alkaline. Many are low in silicates.
mineralization pathway cited at Rock Solid - Energy Futures Initiative