Abstract

Previous experiments simulating the early diagenesis of carbonate ooids in sea water have been continued using skeletal carbonate and carbonate mud as well as carbonate sediment spiked with organic matter. The experiments, lasting 28 days at elevated hydrostatic pressure and at temperatures in the range 180-210 °C, used natural sea water and recent sediments from Florida Bay and the Bahamas. Analyses of the organic and inorganic fraction of the products as well as the gaseous and fluid phases gives insights into the processes of maturation and diagenesis. The results confirm those of the earlier study and those of other workers, and indicate that there are well defined and predictable pathways of organic maturation. The presence of the organic phase appears to control, albeit indirectly through the possible affect of increased phosphate, the transformation from aragonite to calcite.

This, along with other factors also appears to control cementation. The gaseous phase is also important and it may prove possible to trace its evolution by study of fluid inclusions in suitable rocks.