An occurrence of calcite, strontianite, and ankerite in the Pilanesberg Complex, North West Province, South Africa

摘要

Calcite, strontianite, and manganoan ankerite are shown to occur in the Pilanesberg Complex. Carbon and oxygen isotope results, high whole-rock strontium content, and the high strontium content of calcite indicate that the carbonate may be magmatic in origin. The mineral assemblage in the sample is similar to that for late stage, low-temperature, and hydrother-mally altered carbonatites, although the carbonate content of the sample is not sufficiently high for it to be classified as a carbonatite. Although the Pilanesberg has been intruded through Transvaal dolomites, this is an unlikely source of the carbonate.%Daar word aangetoon dat kalsiet, stronsianiet, en mangaanankeriet in die Pilanesberg Kompleks voorkom. Koolstof- en suurstofisotoopresultate, hoe heelgesteente-stronsiuminhoud en die hoe stronsiuminhoud van kalsiet dui dat die karbonaat van magmatiese oorsprong kan wees. Die mineraalversameling in die monster is soortgelyk aan dié van laatstadium-, lae-temperatuur-, en hidrotermaal veranderde karbonatiete, alhoewel die karbonaatinhoud van die monster nie hoog genoeg is om klassifikasie as karbonatiet te regverdig nie. Hoewel die Pilanesberg deur die Transvaaldolomiete ingedring het, is laas-genoemde 'n onwaarskynlike bron van die karbonaat.