Calibration of Australia's fossil record boosts petroleum exploration

21 May 2015

Map of north-western Australia. The Northern Carnarvon, Roebuck, Browse and Bonaparte sedimentary basins are highlighted in green

Sedimentary basins of Australia's
North West Shelf. This is a major
hydrocarbon producing province
and the focus of current
regional-scale stratigraphic work

Recent work by Geoscience Australia to integrate geological interpretations along Australia's margins will provide petroleum explorers in Australia with more comprehensive and reliable stratigraphic data.

Speaking at the 2015 APPEA conference, geologist Tegan Smith outlined how Geoscience Australia is working towards calibrating Australian stratigraphy with the Geologic Timescale 2012, and across sedimentary basins.

The geological timescale is one of the major foundations of geoscience. It has been developed by geologists over the past two centuries to describe and understand the stratigraphy, or rock layers, characterised by a particular fossil or fossil assemblages, that represent different events throughout the Earth's history.

"The International Geological Timescale was last updated in 2013, so regular recalibration of Australia's stratigraphy is needed to ensure that major regional geological events can be correlated across Australia's sedimentary basins," Ms Smith explained.

"This helps to improve the accuracy of geological interpretations, therefore increasing potential exploration success," Ms Smith added.

Geoscience Australia has been undertaking this calibration via a range of techniques, including radiogenic dating, fossil comparisons and chemical analyses. This work underpins and supports research integrating existing stratigraphic schemes, to form comprehensive, unified, up-to-date, regional stratigraphic frameworks.

Geoscience Australia's current regional-scale work in building understanding of our offshore sedimentary basins is focussed on correlations along the Australian continental margins, such as the North West Shelf. Many researchers from different companies and institutions have worked in this region since oil was first discovered in the area in 1953. This has resulted in a range of stratigraphic schemes, currently being integrated by Geoscience Australia in collaboration with State and industry researchers.

Geoscience Australia has also created a series of basin biozonation and stratigraphy charts, providing detailed stratigraphic overviews of Australia's petroleum basins, which are available for download from Geoscience Australia's website. The stratigraphic data is also available in the form of a TimeScale Creator data pack, which is available for use in the free downloadable TimeScale Creator data visualisation tool.

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