ORGANIC GEOCHEMISTRY

Volatile Hydrocarbons

Headspace gas analysis was conducted as part of the standard protocol required for shipboard safety and pollution prevention monitoring. A total of 21 cores from Hole 1209A were evaluated (Table T9). The concentrations of CH4 were at background levels (range = 1.7-2.3 ppmv); no hydrocarbon gases higher than C1 were detected.

Carbonate

Carbonate determinations by coulometry were made for a total of 67 samples from Hole 1209A (Table T10). Samples were selected to provide a measure of the carbonate contents within different units and to assess the influence of carbonate content on color reflectance. The values for carbonate range from 4 to 89 wt% (Table T10) in Unit I, reflecting antithetic variations in the proportions of biogenic silica and carbonate. The profile of carbonate contents shows considerable variation downcore (Fig. F28), which primarily reflects the choice of intervals representative of extremes in color and lithology. The highest carbonate contents measured in Unit II exceed those in Unit I, and variability decreases. The calcareous oozes of the Maastrichtian (Unit III) have uniformly high carbonate contents.

NEXT