Abstract The Bitter Springs Formation constitutes the upper part of Supersequence 1, an 830 Ma carbonate succession deposited in the intracratonic Centralian Superbasin. The Superbasin covered 2 million km 2 of the Australian continent during Neoproterozoic times. We have integrated new carbon, oxygen, sulfur, and strontium isotopic information, and new biomarker information, with existing results, to test and extend previous studies of the formation. The Gillen Member of the Bitter Springs Formation was deposited in a marine environment. The evidence for this interpretation includes isotopes of strontium, carbon, and sulfur, and biomarkers. 87 Sr/ 86 Sr ratios in the Gillen Member are comparable to the lowest ever recorded from the Shaler Supergroup of Canada, of similar age. These low strontium isotopic ratios are associated with comparable secular change in seawater δ 13 O carb . Steroidal hydrocarbon biomarker assemblages, seawater δ 34 S sulfate values, and low δ 34 S pyrite values further indicate a marine origin. The lower part of the Loves Creek Member (Units 1 and 2) was also deposited in a marine environment. Facies-independent secular change in seawater δ 13 O carb and low 87 Sr/ 86 Sr ratios are comparable to those in the upper Shaler Supergroup of Canada. Seawater δ 34 S sulfate , values, low δ 34 S pyrite , and evidence for algal biomarkers are also consistent with marine deposition. The upper part of the Loves Creek Member (Unit 3), and lower part of Unit 2, is nonmarine. Rare pyrite, heavy δ 34 S pyrite , abundant irregularly branched C 25 and C 30 isoprenoids from methanogens, and abundant pseudomorphs after halite indicate carbonate precipitation in sulfate-poor hypersaline lakes. Heavy and variable δ 13 S carb and δ 18 O indicate that continental groundwater brines, which were low in dissolved carbonate, drained into the lakes. Evaporation of the lake waters increased the concentration of dissolved carbonate, and increased still more the δ 18 O values, and may have had a small positive effect on δ 13 C carb . Dolomitization of the continental redbeds occurred by the evaporative reflux of groundwater. Cyanobacteria formed mats on the lake margins, where they were quickly silicified. Domical and irregular stromatolites formed within the lakes. The occasional presence of C 30 desmethyl steranes and 4-methylsteranes in the lower parts of Unit 3 indicates that either there were marine incursions or that marine algae were transported to the lakes, possibly by winds. Nonmarine Neoproterozoic algae may have synthesized these sterols.