Geophysics has changed a great deal since your scribe struggled to make morning lectures after late nights in the university bar (at least on some occasions as one of the many barmen I should clarify). Back then, there was only a hefty tome which doubled as a handy doorstop to describe applied geophysics to the uninitiated – weighing in at around 800 pages and with a warning that it should not be placed too close to gravity meters during their operation.
That famous geophysics text had a significant Canadian slant to it – which when dragged off the shelf years later in Australia unfortunately offered scant insights to the many and varied extra challenges that local geological conditions could often present to mineral explorers.
It has been a long time coming but thankfully the lack of an all-round geophysics text focused on the mineral exploration sector but with particular relevance to Australian explorers has finally arrived. This week your scribe enjoyed spending many hours with his head buried in the recently published Geophysics for the Mineral Exploration Geoscientist* authored by Mike Dentith and Stephen Mudge and released by Cambridge University Press.
Australian geophysics examples are a plenty – although mineral deposits in most other parts of the world make many appearances too.
The strength of the new book is in its breadth – covering all the geophysical techniques that are in common use (and some that are less commonly deployed too). The highlight of the book though lies in the multitude of high quality colour diagrams and images that the book contains.
With technical books such as this which are produced for a specialized market it takes corporate sponsorship to allow such detailed diagrams to be custom drafted and put into print.
For that corporate support all readers should be grateful – and the sponsors of the book are listed below by small way of thanks.**
At 438 pages, the book is comprehensive – and if anything future editions will still have room to grow a little further without becoming unwieldy.
To the content then: Introductory material on the physical and chemical properties of rocks is closely followed by a section on the framing of geophysical data acquisition, processing and interpretation.
Next it is into the details of the methods themselves with gravity and magnetics first-up, followed by radiometrics, electrical and electromagnetic methods – and then finally to seismic.
Those readers seeking further context are directed to a number of appendices – for background material on vectors and wave analysis, magnetotellurics, radio and radar frequency methods and seismic refraction.
The book offers far more than a review of geophysical methods however. Right upfront there is a comprehensive list of the various mineral deposits from around the world that are featured as examples of the geophysical signatures revealed when using the different techniques.
Listing some Australian deposits here as brief examples, the coverage is good. For example, those with a bent towards copper can look at the likes of Balcooma, Blinman, Ernest Henry, Eloise, North Parkes and Olympic Dam (of course).
Gold bugs can look at Pajingo and London Victoria as well as at Golden Cross in New Zealand. Local nickel is well represented too with Mount Keith, Rocky’s Reward and Poseidon. Uranium uses Yeelirrie as the Australian example.
For lead-zinc it is not surprisingly Mount Isa and Broken Hill – but also Dugald River and Elura. The list goes on – and is too long to replicate here – but suffice to say the coverage is good, and includes graphite (including Uley), coal, iron manganese diamonds and potash.
The book is highly recommended and a great addition to a personal library. Let’s hope that the extra insights it provides to geophysical exploration will contribute towards future mineral discoveries.
Good hunting
Allan Trench is professor (value and risk) at the Centre for Exploration Targeting, University of Western Australia, professor of energy and mineral economics at Curtin University Graduate School of Business, a non-executive director to several resources sector companies – and the Perth representative for CRU Strategies, a division of independent metals and mining advisory CRU Group (allan.trench@crugroup.com).
* Michael Dentith abd Stephen Mudge, Geophysics for the Mineral Exploration Geoscientist – Cambridge University Press.438pp.
**AngloGold Ashanti; Carpentaria Exploration; Centre for Exploration Targeting; First Quantum Minerals; MMG; Rio Tinto; St Barbara
