ABSTRACT: Permo-Mesozoic rifting in Gondwanan Eastern Indonesia

Charlton, Tim R. , Consultant, Guildford, Surrey, United Kingdom

Four main phases of rifting are recognised in the sector of the Australian continental margin that now forms Gondwanan eastern Indonesia:

- During the Permian-Middle Triassic, regional extension led tothe development of a major intracontinental rift system characterised by a lower plate rifted margin in what is now the southern Banda Arc (Timor, Tanimbar) and an upper plate margin in the northern Banda Arc (Seram, Buru, Misool, Buton). The two rifted margins were separated by an extended terrane that subsequently became the West Burma Terrane of mainland SE Asia. This extensional system lay inboard of an Andean-type arc through eastern Sulawesi, Banggai-Sula and northern New Guinea. The rifting is interpreted as related to the final separation of the Sibumasu Terrane from Gondwana.

- Middle-Late Jurassic rifting led to the separation of "ArgoLand" (?South Tibet). from west of Australia. The effects of this rifting are recognised in Timor, and also further north on the reconstructed continental margin. Subsequently the SE Sulawesi-Buton region formed a continental margin plateau analogous to the Scott and Exmouth Plateaus on the present western margin of Australia.

- Early Cretaceous (Valanginian) rifting led to the removal ofthe West Burma Terrane as a keystone block from the Banda Embayment. The effects of this event are seen particularly around the Banda Arc, in several places leading to marginal collapse from shelf to abyssal waterdepths.

- Late Cretaceous extension in the Bird's Head region, probably related to continental rifting along the northern margin of New Guinea.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia