ABSTRACT

Techniques have been developed to study the less-than-62-microns fraction of Recent carbonate sediments with the scanning electron microscope. Samples are prepared by pipetting grains suspended in water on to SEM specimen stubs covered with double adhesive tape. The stubs can then be point counted to obtain quantitative information about the constituent particles present.

Samples prepared from crushed fragments of locally important sediment producing organisms were studied to establish criteria by which naturally produced grains in the sediment may be recognized. The identification of grains depends on an understanding of skeletal ultrastructures and increased accuracy will be obtained as more is learned of organic ultrastructure.

The study has shown that virtually all of the 15 to 62 micron size material and much of the less-than-20-micron material can be identified.

In the area studied, there is little to suggest than inorganic precipitation contributes any significant amount of fine-grained material to the sediment, but rather the bulk of the fine-grained material is the result of the disintegration of organic skeletons.