Distribution of organic matter and gases in sediments at DSP Leg 63 Holes

As part of our continuing organic geochemical studies of sediments recovered by the Deep Sea Drilling Project, we have analyzed the types, amounts, and thermal alteration indices of organic matter in samples collected from the California continental margin on Leg 63. Some of the samples were frozen core; others were canned on site. Canned samples were analyzed for gas content using methods described by Mclver (1972). Our main objective was to see if the changes in surface circulation that had occurred through time off the California coast were reflected in changes in the type and amount of organic matter accumulating on the sea floor.

Chemical composition of organic matter in ocean sediments

Group composition of organic matter in recent ocean sediments with high Corg content has been studied in detail. It has been shown that organic matter in sediments with Corg content greater than 4% is present in the very earliest stages of transformation. Group composition of amino acids is practically similar to that of their main producer, namely phytoplankton. Organic matter of sediments with Corg content below 4% is, from this standpoint, more transformed and is close to organic matter in usual type sediments with similar Corg content.