Seram

Indonesia Offshore

On this schematic tectonic sketch, it is quite easy to understand the Ceram trough between the Bird's Head platform and the Banda Sea plate. The Ceram trough can be considered as the continuation of Timor trough (Page 3A) with a small complication on the area of Kai Besar, where a micro-plate boundary, separates the Timor plate (in the southern area) from the Banda Sea plate, which contains part of Sulawesi Island, Ceram Island and Banda Islands.

Ceram Offshore

As illustrated on this cross-section the Ceram (or Seram) trough highlights the limit between the Australian lithospheric plate (plunging plate), and accretionary wedge complex (imbricated stacking of the Australian Mesozoic to Miocene) of the overriding plate (see next autotrace). The evolution of the north Ceram offshore is related (i) to the separation of blocks at the northern Australian Atlantic-type, (ii) the extension and formation of the Tethys Sea and (III) the collision of the Banda landmass with the Australian. Such an evolution evolution can be divided into five stages: a) Initial riffing during the Early Triassic ; b) Late rifting during the Middle Triassic-Middle Jurassic ; c) Breakup unconformity (probable during the Middle Jurassic) ; d) Deposition of an Atlantic-type divergent margin, during the Late Jurassic-Middle Miocene passive, and e) Thrusting during the Late Miocene-Quaternary.

The Ceram fold belt is associated with the collision between an island arc (Banda Sea plate, see Page) and Bird's Head plate of western New Guinea, which is a minor lithospheric plate containing the Bird's Head Peninsula, separating from Australian plate and the small Maoke plate along a divergent boundary. Convergent boundaries exist in the north with Bird's Head, in the southwest with the Molucca sea collision zone and between thew Bird's Head and the Banda sea plate in the south. On this Canvas tentative geological interpretation of a Canvas autotrace, it is easy to recognize the overriding plate (Banda sea plate), which is strongly shortened while the descending plate (Bird's Head plate) keeps the original extensional structures.