Palaeozoic Palaeomagnetism of South-Eastern Australia
type: CreativeWork
description: The drift history of Gondwana following the break-up of Rodinia (or perhaps Pannotia) to the amalgamation into Pangaea has great implications in many disciplines in Earth sciences, but remains largely unknown. Among the apparent polar wander (APW) paths published for Gondwana in the last few decades, large discrepancies exist (sometimes up to thousands of kilometres). The mid Palaeozoic segment of the APW path is particularly problematic, and two primary schools of thought arise. Some authors favour a Silurian – Devonian loop in their APW path passing through southern South America (on a reconstruction of Gondwana), whereas others draw a path directly through Africa during this period. The main controversy stems essentially from whether or not palaeomagnetic data from eastern Australia are incorporated in order to compensate for the lack of mid Palaeozoic data. Determining whether the terranes of the Southern Tasmanides are (para-)autochthonous or allochthonous in origin is therefore of crucial importance and a matter of intense debate. The aim of the work presented herein is to palaeomagnetically define the positions of these terranes throughout the Palaeozoic in order to better constrain the complex tectonic history of this region and to help clarifying the APW path of Gondwana. The construction of an APW path is discussed herein. An attempt is made to determine whether only “objective” criteria can be employed to select data used to draw an APW path. However, it is shown that the palaeomagnetic database has not enough entries. Subjective data selection must be introduced leading to two end-members: the X-type and the Y-type, thought to be best illustrated by the X-path proposed by Bachtadse & Briden (1991) and the Y-path proposed by Schmidt et al. (1990). These two models are, therefore, used in the discussion of the results obtained for this study. The Southern Tasmanides had a complex tectonic history with several orogenic events throughout the Palaeozoic. The …
abstract: The drift history of Gondwana following the break-up of Rodinia (or perhaps Pannotia) to the amalgamation into Pangaea has great implications in many disciplines in Earth sciences, but remains largely unknown. Among the apparent polar wander (APW) paths published for Gondwana in the last few decades, large discrepancies exist (sometimes up to thousands of kilometres). The mid Palaeozoic segment of the APW path is particularly problematic, and two primary schools of thought arise. Some authors favour a Silurian – Devonian loop in their APW path passing through southern South America (on a reconstruction of Gondwana), whereas others draw a path directly through Africa during this period. The main controversy stems essentially from whether or not palaeomagnetic data from eastern Australia are incorporated in order to compensate for the lack of mid Palaeozoic data. Determining whether the terranes of the Southern Tasmanides are (para-)autochthonous or allochthonous in origin is therefore of crucial importance and a matter of intense debate. The aim of the work presented herein is to palaeomagnetically define the positions of these terranes throughout the Palaeozoic in order to better constrain the complex tectonic history of this region and to help clarifying the APW path of Gondwana. The construction of an APW path is discussed herein. An attempt is made to determine whether only “objective” criteria can be employed to select data used to draw an APW path. However, it is shown that the palaeomagnetic database has not enough entries. Subjective data selection must be introduced leading to two end-members: the X-type and the Y-type, thought to be best illustrated by the X-path proposed by Bachtadse & Briden (1991) and the Y-path proposed by Schmidt et al. (1990). These two models are, therefore, used in the discussion of the results obtained for this study. The Southern Tasmanides had a complex tectonic history with several orogenic events throughout the Palaeozoic. The …
author: Vérard, Christian
date published: 2004-06-02
date modified: 2026-07-24T02:51:58Z
provider: Ludwig Maxmilians Universität München
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Ludwig-Maximilians-Universität