Research project: Tasman margin age-dating, East Australia

Dates

Start date:
1990

Museum investigators

  • Lin Sutherland
  • Ross Pogson

External investigators

  • Ian Graham, University of New South Wales
  • Robin Offler, University of Newcastle
  • H. Zwingmann, CSIRO, Perth
  • John Everard,
  • Steve Forsyth , Geological Survey Tasmania
  • Julian Hollis, Trentham, VIC
  • Neil Thomas,
  • Alex Garcia, University Kingston

Funded by

  • Australian Museum

Description

Tasman rifting and seafloor spreading altered the geological evolution of East Australia by creating an uplifted margin, high heat flows and ongoing basaltic and silicic volcanism. These features changed landscapes, drainages, and erosion rates. Dating the involved rocks untangles the compound events and helps to interpret them within the broad scale tectonic settings and past magnetic fields.

Various techniques were used in dating the rocks and associated minerals (K-Ar, Ar-Ar, zircon fission track, zircon U-Pb isotopes) and in analyzing their compositions (EMP, XRD, LA-ICPMS, SHRIMP).

The results so far have built up profiles through local areas, correlated biozones in Bassian basins, and provided frameworks for tectonic events in regions such as the New England and Barrington Tops plateaus in New South Wales, the North Queensland lava fields and the Tamar Valley, Tasmania. They have fed into syntheses of the overall eruptive history of East Australia. Many of these results have been published in international and Australian journals, including special publications of the Geological Societies of Australia and America and the American Geophysical Union. They have provided input into major Cenozoic dating data bases complied by Geoscience Australia and the Geological Society of Australia.

Present studies are investigating the basalt dyke systems along the Tasman margin and the related inland lava fields in the Yarrowitch and Tumberumba areas in New South Wales and across Tasmania.


Lin Sutherland
Ross Pogson
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