Tectonic cycles of the New England Orogen, eastern Australia: A Review

Abstract

The New England Orogen (NEO), the youngest of the orogens of the Tasmanides of eastern Australia, is defined by two main cycles of compression–extension. The compression component involves thrust tectonics and advance of the arc towards the continental plate, while extension is characterised by rifting, basin formation, thermal relaxation and retreat of the arc towards the oceanic plate. A compilation of 623 records of U–Pb zircon geochronology rock ages from Geoscience Australia, the geological surveys of Queensland and New South Wales and other published research throughout the orogen, has helped to clarify its complex tectonic history. This contribution focuses on the entire NEO and is aimed at those who are unfamiliar with the details of the orogen and who could benefit from a summary of current knowledge. It aims to fill a gap in recent literature between broad-scale overviews of the orogen incorporated as part of wider research on the Tasmanides and detailed studies usually specific to either the northern or southern parts of the orogen. Within the two main cycles of compression–extension, six accepted and distinct tectonic phases are defined and reviewed. Maps of geological processes active during each phase reveal the centres of activity during each tectonic phase, and the range in U–Pb zircon ages highlights the degree of diachronicity along the length of the NEO. In addition, remnants of the early Permian offshore arc formed during extensive slab rollback, are identified by the available geochronology. Estimates of the beginning of the Hunter-Bowen phase of compression, generally thought to commence around 265 Ma are complicated by the presence of extensional-type magmatism in eastern Queensland that occurred between 270 and 260 Ma.

Keywords:

• Tectonic cycles
• zircon U–Pb geochronology
• New England Orogen
• slab rollback
• extension
• GIS maps

Acknowledgements

Many thanks to Peter Flood, Richard Flood, Elena Belousova, Robin Offler and Paul Ashley for providing valuable input to both data collection and review. The willing help of other researchers of the NEO including Evan Leitch, Rod Holcombe, Gideon Rosenbaum, David Champion, Bob Henderson and Sean McKibbin is also acknowledged. Feedback from thesis reviewers Chris Fergusson and Paul Lennox has been incorporated into the manuscript and is similarly appreciated. The authors would also like thank Evan Leitch and Uri Shaanan for reviewing this contribution and their helpful input to clarify text and highlight research that needed inclusion.

This is contribution 1185 from the ARC Centre of Excellence for Core to Crust Fluid Systems (http://www.ccfs.mq.edu.au) and 1241 in the GEMOC Key Centre (http://www.gemoc.mq.edu.au).

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary papers

Appendix A: Zircon ages of magmatic rocks from the New England Orogen (Excel file).

Additional information

Funding

This review was undertaken as part of PhD research under an APA scholarship.