The occurrence of cuspidine, foshagite and hillebrandite in clac-silicate xenoliths from the Bushveld Complex, South Africa.

The rare calc-silicate minerals cuspidine, foshagite and hillebrandite occur as late phases in calcsilicate xenoliths from the Rustenburg Layered Suite of the Bushveld Complex. These minerals occur in narrow veins or as replacements, particularly after melilite (cuspidine and hillebrandite) or vesuvianite (foshagite). Cuspidine formed early during cooling, possibly under low-XH[sub 2]O conditions. In contrast, foshagite and hillebrandite formed late in the cooling history, after the infiltration of H[sub 2]O-rich fluids that led to the development of locally pervasive vesuvianite. [ABSTRACT FROM AUTHOR]