Microcrystalline dolomite forms a major constituent of Holocene sediments of numerous continental, saline playa lakes in southeastern Australia. The lake waters are highly supersaturated with respect to dolomite as well as other Mg carbonates, but undersaturated or near saturation with respect to calcite and aragonite. The dolomite shows no replacement textures and most likely formed by direct precipitation. Conditions in these lakes that appear conducive to the precipitation of dolomite are (1) high salinity, (2) high Mg/Ca ratios, and (3) high alkalinity. The moderate sulfate levels of the brines do not seem to be inhibiting carbonate precipitation.

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