Some Palaeozoic‐Mesozoic stratigraphic‐structural relationships in east timor and their significance in the tectonics of timor

Abstract

An ‘autochthon’ model for the tectonic development of Timor is suggested, based on observations of Palaeozoic‐Mesozoic relationships from a broad area of central East Timor, including: The model is supported by recent modifications in palaeogeographic interpretations for the Permian of north Australia (e.g. Powell, 1976; Thomas, 1976). Our observations support and extend the earlier suggestions of Grady (1975), and the resulting model is in contrast with some of the hypotheses of Audley‐Charles and his associates (as, most recently, Barber et al., 1977), Fitch & Hamilton (1974), Hamilton (1973, 1976), and Crostella (1976). Our model involves no essentially allochthonous pre‐Cainozoic material in Timor. The Permian to Cretaceous units are envisaged as developing on the continental margin which was dominantly inactive, but affected to some extent by Late Jurassic rifting activity. Following the Pliocene collision with the Inner Banda Arc, uplift along the collision zone would have caused gravity gliding towards the south. Thus, surficial olistostrome deposits, originally from the island arc, could have eventually moved to the northern slopes of the Timor Trough, while at depth, reverse faulting could have developed as a result of gravity gliding. We maintain that previous postulates of a pervasive, strongly imbricate structure for Timor, lack adequate substantiation in the literature. Furthermore, accounts of the tectonic development of Timor, involving large scale translation on low angle faults, are even less well substantiated.