Carbon isotope geochemistry of the Precambrian Lomagundi carbonate province, Rhodesia

Carbon isotope measurements carried out on 67 dolomite samples from the Middle Precambrian Lomagundi Group (Rhodesia) have yielded a δ ¹³C mean of +8.2 ± 2.6%. vs PDB. With the outcrop of these dolomites extending over a distance of almost 300 km, the Lomagundi dolomite faces is likely to represent the largest isotopically anomalous sedimentary carbonate province ever recorded. It is concluded that the anomalous carbonates formed in a closed basin whose δ ¹³C level had been substantially increased as a result of a preferential removal (within sedimentary organics) of the light carbon isotope.