Calcium carbonate weight percent and mass accumulation rates of ODP Site 145-883

Here we present new and shipboard calcium carbonate weight percent and mass accumulation rates in discrete samples from ODP 883B. 71 accelerated solvent extractor sample residues were analyzed for calcium carbonate to supplement the 23 measurements in our study interval made by the shipboard scientific party (total N = 94). Approximately 30–60 mg of freeze-dried sediment was weighed prior to analysis in a UIC Coulometrics CO2 Coulometer in the Marine Analytical Lab at the University of California, Santa Cruz. Samples were acidified with 2 M HS and heated to 60°C. Measured C was converted to CaCO3 by a conversion factor of 8.33, determined by dividing the molecular weight of CaCO3 by that of C. Measurement error was ±1.85%, determined by repeated analysis of a homogenized laboratory standard calcium carbonate. Calcium carbonate mass accumulation rates were calculated as the product of weight percent CaCO3, dry bulk density, and sedimentation rate. Sedimentation rates were derived from the ODP 883 orbitally tuned age model presented in this study. Dry bulk density was estimated using the relationship between GRAPE WBD and measured dry bulk density in cores 9H–19H from hole 883C . CaCO3 weight percent was correlated to GRAPE WBD from hole 883B by resampling GRAPE WBD to the CaCO3 data using the "approx" function in .R.