Abstract

The Pulau Seribu in the western Java Sea are an excellent example of a modern patch reef province in Indonesia. Their growth patterns are influenced by their position on the northeast – southwest trending Seribu High and by the influence of the seasonal wind and current directions.

Morphologically, they tend to be small, elongate reefal bodies varing in length from 50 metres to a kilometre or more. They are steep sided and separated by flat-bottomed, east-west channels. Their edges are characterised by prolific growths of living corals.

Preliminary studies of their morphology and sediments have given rise to theories concerning their growth, and have allowed the distinction of a number of physiographic zones and sedimentary facies. Particular attention has been paid to the skeletal components of the sediments in the various facies and it appears that they are almost all composed chiefly of coral and molluscan debris, with smaller proportions of echinoid, foraminiferal and algal material, while the primary influence on the growth of the predominant current direction, ecological and sedimentological observations have shown the importance of biological activity in the generation, reworking and redistribution of the sediments.

The palaeoecological significance of the observations to date is dicussed in an attempt to bring out some features which will be useful in the interpretation of Neogene reefal bodies in Indonesia.