An Australian research paper published in the Nature Geoscience journal is attracting international attention for its findings that demonstrate a link between seismic activity and the precipitation of gold and other trace elements in earthquake fault zones.
Paper co-authors, Dr Dion Weatherley, Senior Research Fellow at The University of Queensland's Sustainable Minerals Institute, and Professor Richard Henley, Visiting Fellow at The Australian National University's Research School of Earth Sciences, confirmed the link following a collaborative research project that began just 18 months ago.
According to Dr Weatherley, combining their expertise in geochemistry and seismology disciplines proved to be a critical factor in developing the simple mathematical model that would test Dr Henley's hypothesis about the speed at which precipitation of gold and quartz occurs.
“While geochemical and geological evidence has long alluded to a connection between earthquakes and the deposition of gold, there has been much debate through the decades as to whether the precipitation of gold was a slow, equilibrium process or whether, as Professor Henley was proposing, it was a rapid and far from equilibrium process,” Dr Weatherley said.
The mathematical model developed through the research process suggests that seismic activity could be one of the primary mechanisms for the formation of economical and mineable ore deposits, according to Dr Weatherley (pictured alongside).
“The most surprising finding we made was that even very small magnitude earthquakes of four and smaller can generate sufficient pressure reduction within fault jogs to initiate flash precipitation of gold and quartz during the earthquake itself,” Dr Weatherley said.
“While the amount of gold that would be deposited in any one earthquake is quite small, when you consider that tens or hundreds of magnitude four quakes and thousands of smaller magnitude quakes may occur each year within an earthquake fault system, the possibility exists that over time, large gold deposits may result.”
The research findings challenge traditional mine geologic thinking around the formation of quartz veins under equilibrium conditions, rather suggesting a more rapid process that goes on to deposit gold in fault zones. Not surprisingly, the findings have attracted great interest from the geosciences community.
“We are hopeful that any deeper understanding we can gain about the physical processes that form ore bodies may help exploration geologists find new mineable gold and other mineral deposits,” Dr Weatherley said.
“Most of the world's ore deposits that are exposed at the earth's surface have either been found or already mined. Our research paper aims to reveal new findings and knowledge about the physical processes that will assist exploration geologists to discover blind ore deposits that are deeper within the earth.”
The mining resources of the Sustainable Minerals Institute are centrally located within the W.H. Bryan Mining and Geology Research Centre (BRC).
Established in 1991, the BRC conducts research to reduce geological and mining risk, and to optimise mining procedures to meet the complex challenges facing the global mining sector.
The Centre delivers strategic technologies and engineering solutions, in pursuit of effective and sustainable industry practice.
[Purchase Dr Weatherley and Dr Henley's paper.]