Timor- Tanimbar Trough: the foreland basin of the evolving Banda orogen.

Abstract

Seismic refraction surveys indicate the 2-3km deep, 1200km long and locally up to 70km wide Timor-Tanimbar Trough is underlain by continental crust varying (W to E) between 31 and 40km thick. Seismic reflection surveys indicate this Trough is underlain by downbowed Australian continental shelf overlain on the Banda Arc (N) side by a series of reflectors that dip northwards away from the Australian margin. These reflectors appear to represent a pile of thrust sheets composed of Australian continental margin sedimentary rocks that have moved towards the Australian continent. Immediately south of the Outer Banda Arc islands these reflectors are overlain by seismically chaotic material which is itself overlain locally by a reflective, well bedded section interpreted as Plio-Pleistocene turbidites derived from the rising Banda orogen. The stratigraphy and structure exposed in the islands of Timor and Tanimbar and the stratigraphy in wells on the Australian shelf are compared with the seismic survey data for the Trough separating these islands from the Australian shelf. These data, and the drilling results from DSDP site 262 are used as a basis for discussion of the Neogene-Quaternary evolution of this foredeep of the Banda collisional orogen. -from Author