Five interstitial water samples were collected from a thin drape of Neogene sediments (0-66.1 mbsf) that unconformably overlies an Upper to Lower Cretaceous sequence. Details of analytical methods can be found in "Inorganic Geochemistry" in the "Explanatory Notes" chapter. Filtered (0.45 µm) samples were analyzed for pH, salinity, chlorinity, alkalinity, sulfate (SO42-), phosphate (HPO42-), ammonium (NH4+), silica (Si(OH)4), boron (H3BO3), iron (Fe2+), manganese (Mn2+), and major cations (Na+, K+, Mg2+, Ca2+, Li+, Sr2+, and Ba2+). A compilation of data is provided in Table T17.
Rotary coring at Site 1213 caused significant disturbance of Cores 198-1213A-1R to 7R, making it difficult to recognize primary sedimentary structures and textures (see "Lithostratigraphy"). The drilling disturbance appears to have also affected the samples obtained for interstitial water analyses, most of which have seawater-like chemistries but elevated Fe2+ and Mn2+ concentrations (Table T17). As such, the geochemical results suggest that samples consist of varying mixtures of pore water and drilling water (i.e., surface seawater) and do not provide a reliable reflection of sediment geochemistry and diagenetic processes at Site 1213.