The new mineral, the iron analogue of monticellite, occurs in melilite-nephelinite Iava from Mt. Shaheru, Belgian Congo, associated with melilite, nepheline, clinopyroxene, kalsilite, gdtzenite, combeite, sodalite, magnetite, perovskite, apatite, hornblende, biotite, and an unident i f ied mineral . Analysis gave SiO2 32.77,TiO20.23, AIzOa0.26, Fe2Oa 0.66, FeO 29 34, MnO 1.65, MgO 4.95, CaO 29....

Nyiragongo volcanic eruptions of 1977 and 2002 emitted silica-undersaturated lavas named melilite-nephelinites with microlithic to sub-porphyritic textures, consisted olivine, clinopyroxene (augite), phlogopite, melilite, magnetite, rare plagioclases. This melilite-nephelinite as an evolved rock, shows low SiO2 (38.40 - 39.52 wt%) MgO (3.10 4.01 wt%), relatively high FeOt (13.76 14.10 Al2O3 (15...

Mantle xenoliths in a nephelinite the Little Lottery River provide insight into Miocene mantle adjacent to Australia-Pacific plate boundary N Canterbury. The comprise peridotite and pyroxenite extracted from depths of ∼ 40 60 km. olivine Mg# < 89, lack spinel occurrence ilmenite, elevated bulk Cr Al, light rare Earth element (REE)-enriched clinopyroxene, 87Sr/86Sr15 Ma clinopyroxene populations...

Abstract Maio Island (Cabo Verde Archipelago) is composed of uplifted Early Mesozoic MORB-type pillow lavas and deep-sea sediments, unconformably overlain intruded by Miocene igneous rocks. Combined structural analyses 40 Ar– 39 Ar dating were used to constrain the evolution Maio. Structures ages sequences crosscutting dykes showed that numerous intrusive events associated with intense growth a...