Wednesday, 22 September

Was Cooper Basin hit by a large asteroid 300 million years ago?

Today I will report on something quite exciting.

I will give you a summary of a paper the QGECE Reservoir Geology Program Leader Dr Tonguc Uysal and DR Andrew Glikson of ANU will be presenting at the forthcoming Australian Geothermal Energy Conference in Adelaide. Click here to get a full copy of the paper and attend the Conference for a more detailed justification on why Drs Uysal and Glikson think Cooper Basin may have been hit by a major asteroid about 300 million years ago.

The confirmation for the asteroid hit comes from a microscopic examination of the quartz crystals from rocks underlying the Cooper Basin by DR Tonguc Uysal (QGECE) followed by laboratory tests by DR Andrew Glikson of the Australian National University (ANU). Shock features were found in drill holes spaced as far as 80 kilometres across. Other known examples of large impact structures include the Woodleigh impact (Western Australia; 120 km-diameter; ~360 million years ago), Popigai impact (Siberia; 100 km-diameter; 35.7 million years ago) and Chesapeake Bay impact (off-shore Virginia; 85 km-diameter; 35.3 million years ago). Such structures are formed by the impact of asteroids 6 - 8 km-large.

The impact-triggered explosion, circulation of boiling groundwater and mobilization and reconcentration of radiogenic elements, all may have helped the creation of major geothermal anomalies under the Cooper Basin. Drs uysal and Glikson report that the precise age of impact is yet to be determined, possibly through isotopic studies of clay minerals in the altered zone. Further studies of impact shock metamorphic effects on samples from drill holes in the Cooper Basin in South Australia are required in order to define the extent of the impacted aureole.

 

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