Sediment depth is given in mbsf. Blank spaces indicate that no data were obtained. The composition of the protodolomites was calculated as follows: The Ca/Al, Mg/Al, and Fe/Al ratios were corrected for background values calculated for the nondolomite sediments (Ca/Al = 0.4 upper 150 m, Ca/Al = 0.1 below 150 m; Mg/Al = 0.3 upper 150 m, Mg/Al = 0.2 below 150 m; Fe/Al = 0.2 below 150 m). The percentage of CaCO3, MgCO3, and FeCO3 was then calculated from the corrected ratios. It was assumed that all other constituents of the protodolomites were <1%. The estimated errors were ± 3% of the CaCO3 value, ±4% of the MgCO3 value, and ± 10% of the FeCO3 value. These estimated errors were obtained by taking a low and a high correction for Ca/Al, Mg/Al, and Fe/Al and calculating the spread for the corrected values of several samples containing high Al.