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Shaping a Nation: A Geology of Australia

Shaping a Nation: A Geology of Australia. Geoscience Australia, 2012, Richard Blewitt, Chief Editor, 571 pages
This article appeared in Vol. 10, No. 2 - 2013

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Weathering has resulted in the formation of abundant iron oxides, giving the Australian landscape its distinctive red colour. Ayers Rock (Uluru) is probably the most famous landform in Australia. It consists of steeply dipping sandstones of Cambrian age and stands some 348m above the surrounding plane. Australia is largely covered by weathered rocks (regoliths), and Ayers Rock can be looked upon as an erosional remnant. Source: Ingvild Carstens Australia’s defining moment came 34 million years ago when the continent rifted from Gondwana. The separation released it from cold high-latitudes, allowing it to drift northward into the subtropical high, where it has been for the last 10 million years.

The continent itself is, however, home to some of the oldest rocks in the world, some dating back to 3.7 billion years. Even more intriguing, a detrital zircon grain from Western Australia has an age of more than 4.4 billion years. (The Earth is close to 4.6 billion years.)

This voluminous book about the geology of (mostly onshore) Australia is not another book about rocks, minerals and fossils catalogued through time. It is thus not only about how the geological history has shaped the continent where the Aussies live, it is also about how the geological history has influenced Australia’s human history and the way they live. It is about how underlying geology has created a nation and a society.

We therefore totally agree with Martin Ferguson, Minister for Resources, Energy and Tourism, who says in the introduction that this book ‘demonstrates the fundamental importance of the study of Earth sciences to our society’.

For this reason, this well-illustrated book is quite different from many other popular geoscience books, just because it emphasizes why geology is important to our society – which also explains why it does not start with the birth of the Solar System, continue with the Precambrian and end up in the Quaternary. While geological time is key to the understanding of geological history, it is even more important to realize that we study geology because we can make use of geological knowledge to shape a nation. This is what makes this book unusual. And – above all – interesting to read.

Wide Range of Topics

Consequently, the eleven chapters deal with topics like ‘Groundwater – lifeblood of the continent’; ‘Foundations of wealth – Australia’s major mineral deposits’; and ‘Deep heat – Australia’s energy future’.

True to its intentions, the book starts with a chapter about the demography, history and culture of ‘Australia and the Australian people’, including geography (nicely illustrating that its size is equivalent to the US lower 48), landscape (‘the flattest on Earth’), climate (flush with ultraviolet light resulting in the highest skin cancer rates in the world), flora (certainly a lot more than the plentiful fossil record), fauna (of the 869 reptiles, 773 are found nowhere else), resources (utilization started with the aboriginals, while the discovery of copper saved the colony from early ruin) and geohazards (largely cyclones, floods, droughts, heatwaves and bushfires).

Chapter 4 – Out of Gondwana – will probably be the favourite for petroleum geoscientists who want to know more about the Australian petroleum systems. Above all, it shows how Australia emerged from the supercontinent of Gondwana, but the breakup process is closely linked to where coal, oil and gas are found. While Paleozoic basins contain some fossil fuels, the Mesozoic marginal basins, which were created as Gondwana broke apart, contain 90% or more of Australia’s conventional oil and gas. Most of the oil was originally in the Gippsland Basin (between Australia and Tasmania). The majority of the gas accumulations are on the North West Shelf.

Petroleum exploration in Australia began in earnest in the 1860s, resulting in a few modest shows. Surface oil seeps are not common, meaning low activity for almost hundred years, and it was not until 1953 that the first flow of oil occurred (Rough Range 1 in the onshore Carnarvon Basin). By the early 1960s, the momentum on exploration had been built and discoveries came along with increased drilling. By 1972, all the major basins and petroleum systems that are today producing hydrocarbons had been found.

Australia is certainly a fascinating country: huge, by any standard, and tons of geology to offer that can be studied in a warm and pleasant climate. No one with an interest in geology should, however, ever consider going there without having spent considerable time on this book. It is a valuable trip planner for the curious geoscientist.

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