New zealand and south-east australia in the early paleozoic

Abstract

The early Paleozoic geological histories of New Zealand and south-east Australia are generally consistent with the hypothesis that they formed part of a single segment of Gondwanaland in the Paleozoic. The main events of their sedimentary, igneous, and tectonic histories are summarised and compared. Within south-east Australia, Central Victoria compares remarkably closely with New Zealand; the main events in volcanic and plutonic activity, trough deposition, and diastrophism can be matched in the two regions. The Eastern and Western Belts of trough deposits and interposed central volcanic belt of New Zealand are the direct analogues of the Ballarat and Melbourne Troughs and interposed Heathcote Axis, of Central Victoria. These analogous belts may have been continuous in the Cambrian and Ordovician. In contrast, Central Victoria apparently bears no close resemblance to its neighbouring regions, East Victoria-New South Wales and Tasmania, especially in late Precambrian to Ordovician time. Large scale horizontal displacements of regional blocks within the south-eastern segment of Gondwanaland seem probable, and apparently took place during Silurian or earliest Devonian time. Some recently suggested early Palezoic large scale fault movements are discussed, and a tentative model for the development of the area is suggested. © 1975 Taylor & Francis Group, LLC.