Headspace gas analysis was conducted as part of the standard protocol required for shipboard safety and pollution prevention monitoring. A total of 12 cores from Hole 1211A were evaluated (Table T9). The concentrations of CH4 were at background levels (range = 1.7-1.9 µL/L [ppmv]); no hydrocarbon gases higher than C1 were detected.
Carbonate determinations by coulometry were made for a total of 35 samples from Hole 1211A (Table T10). Samples were selected to provide a measure of the carbonate content within different units and to assess the influence of carbonate content on color reflectance. The values for carbonate range from 59 to 89 wt% (Table T10; Fig. F21) in Neogene Unit I, reflecting variations in the proportions of carbonate, clay, and silica. The intervals with low values from Unit I are enriched in clay and siliceous microfossils. Carbonate contents in Unit II are higher (mean = 93.4 wt%) and increase further in the Maastrichtian Unit III (median value = 97.0 wt%).