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Lithosphere structure and dynamics of the Banda Arc collision zone, Eastern Indonesia

1993; Geological Society of Malaysia; Volume: 33; Linguagem: Inglês

10.7186/bgsm33199308

2637-109X

Adrian Richardson,

High-pressure geophysics and materials

Timor and adjacent islands in Eastern Indonesia are the site of a currentl~ active col~ision between the Australian continental shelf and the volcanic islands of the Banda Arc. PreVIously pubhshed sedimentological and micro-paleontological data from the islands and the subduction trench date the start of this collision at 2.5 to 3 Ma. Previously published work on seismicity in the Banda Arc shows the geometry of the subduction zone to be fairly simple and continuous down to below 650 km depth. In this paper, the geometry of both the top and bottom surfaces of the subd~cting sla~ is mapp~d to a hl:gh~r degree of accuracy than before. The edge of Australia, which was preVIously a rifted paSSIve margm, IS shown to be markedly thickened in the collision zone itself and has been subducted to a depth of about 200 km. In addition, it appears that the subduction zone has major lateral and vertical discontinuities at depth. It is proposed that these discontinuities reflect slab separation during a previous micro­ continental collisional event some 10 to 7 million years ago and that this collision was related to the transfer of continental lithosphere from the Indo-Australian plate to the South East Asian plate.