(Tables 1-2) Chemical composition of basal metalliferous sediments at DSDP Site 9-80

Samples were divided into three aliquots. The first aliquot was leached with an excess of 1 M acetic acid to remove calcium carbonate. CaCO3 contents of each sample were determined by analysis of these leach solutions for Ca by AAS. The second aliquot consisting of bulk sediment was analyzed for Mg by the standard additions technique of AAS. The third aliquot of each sample was attacked with a mixed acid-reducing agent [1 M hydroxylamine-HCl and 25% (v/v) acetic acid] following the procedure of Chester and Hughes (1967, doi:10.1016/0009-2541(67)90025-3). Data for CaCO3 contents are given for dry bulk sediments; other data are given on a carbonate-free basis. Unlike Fe and Mn, the Mg present in CaCO3 was found to make up a relatively significant part of the overall content of this element in the bulk sample. Therefore Mg concentration in the calcium carbonate fraction was subtracted from the total Mg content prior to the CFB calculation. […]