Geochronology and the evolution of Australia in the Mesozoic

Abstract

The Mesozoic geological history of the Australian continent saw the dispersal of Gondwana, of which Australia was part, and a change from progressive accretion of crust to the eastern one-third of the continent to a passive margin as the subduction zone moved much further to the east. The development of new seafloor adjacent to the west, south and east coasts of the continent records the breakup history and the formation of the Australian tectonic plate which has moved in an essentially northerly azimuth away from Antarctica over much of the last 100 million years. Geochronology directly or indirectly through various time-scales, in concert with many other disciplines, has played a significant role in our present understanding of the Mesozoic geological history of Australia. The role of these time-scales in the interpretation of the geological evolution of Australia during the Mesozoic is highlighted, the final stages of development of the Tasman Fold Belt are briefly discussed, and the widespread tholeiitic magmatism in Tasmania during the Middle Jurassic is examined again in the broader context of similar magmatism across Antarctica and into southern Africa.

Key Words:

• Australia
• geochronology
• Gondwana
• magmatism
• Mesozoic
• seafloor spreading
• Tasman Fold Belt

Acknowledgements

I thank Ian S. Williams and Janet Hergt for providing helpful comments on a draft of the manuscript.