New accessory minerals at Evate deposit in Mozambique

This thesis is focused on new accessory minerals which we found at Evate deposit in Mozambique. The Evate deposit is one of the largest phosphate deposits connected with carbonatites in the south-east Africa. New accessory minerals are zirconolite, monazite, baddeleyite, allanite, zircon, thorianite, sulphates (gypsum, calzirtite, barite). The most examined mineral until now is zirconolite, forming two generations. Zirconolite I is older and creates rims around baddeleyite, zircon, magnetite and geikielite. Zirconolite II is younger and creates grains in μm size. The most typical substitutions in zirconolite are: REE+ACT→Ca, M²⁺M⁵⁺→Ti, M²⁺+M⁵⁺→Ti+M³⁺ and REE+M²⁺→Ca+M³⁺. The chemical composition of zirconolite is described by REE-ACT-M⁵⁺(Nb+Ta) diagram. Zirconolite I has increased content of REE+M⁵⁺ and falls into the area of carbonatites. Zirconolite II has increased content of ACT and falls into the area of metasomatic rocks, which was confirmed also by their chemical composition. (authors)