Headspace gas analysis was conducted as part of the standard protocol required for shipboard safety and pollution prevention monitoring. A total of nine cores from Hole 1212A were evaluated (Table T9). The concentrations of CH4 were at background levels (range = 1.8-2.1 µL/L [ppmv]); no hydrocarbon gases higher than C1 were detected.
Carbonate determinations by coulometry were made for a total of 26 samples from Hole 1212A and 11 samples from Hole 1212B (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 content range from 53 to 90 wt% in Pleistocene to middle Miocene nannofossil ooze of Unit I (Table T10; Fig. F20); lower values correspond to intervals enriched in clay or silica. Nannofossil ooze of Unit II (Paleogene) contains uniformly high carbonate values (mean = 95.9 wt%; standard deviation = 0.81) that are marginally less than those of Unit III (Cretaceous) (mean = 96.7 wt%; standard deviation = 0.31).