Continental depositon of Antarctic tillite indicated by carbon and oxygen isotopes

Freshwater deposition of the upper Paleozoic, Gondwana tillite in the Pensacola Mountains is indicated by low δ values of +4.9 to +6.1 permil δ0 ^{1 8} (SMOW) and -1.8 to -15.9 permil δC^{1 3} (PDB) in primary sedimentary calcite within the tillite. In contrast, Cambrian marine limestone from the Pensacola Mountains contains heavy isotopic abundances that are entirely characteristic of marine deposition.