Abstract

Two carbonate platforms developed within Irian Jaya during Tertiary time; the Arafura Platform with sparse well and outcrop data and the better documented Ayamaru Platform in the Doberai (Vogelkop) Peninsula.

The Ayamaru Platform deposits, which include the New Guinea (Limestone) Group, consist primarily of shallow, quiet water carbonates with interspersed algal and coral patch reefs ranging in age from Eocene to Upper Miocene. These carbonates interfinger with time equivalent deeper marine pelagic limestones of the surrounding basinal areas. The interfingering is the basis for a subdivision the Group into several formations.

Clastics were shed onto the Ayamaru Platform area after uplift along its northern border in both the Oligocene and again in the Upper Miocene. The latter influx of clastic material terminated the carbonate sedimentation.

Outcrops in the northern part of the Bintuni Basin, along the former platform margin exhibit good examples of the lateral facies changes from platform toward a basinal deep.