Australian-first metamorphic diamonds find

James Cook University researchers have located metamorphic diamonds west of Paluma in a discovery set to increase understanding on how the eastern coast formed. The research team confirmed the presence of metamorphic diamonds in rocks along the Clarke River Fault, North Queensland - the first time they have been located in Australia. Related: Diamonds pave way to critical minerals trove But before any would-be prospectors head out to find their own shiny rock, JCU Economic Geology senior lecturer Dr Ioan Sanislav warns the diamonds are invisible to the naked eye. “Don’t go to Paluma and start looking for them. Even for us, it was very difficult to find them,” he said. “We had to analyse many, many thin sections of rock, and to prove the diamonds were there, it took about a year-and-a-half.” Dr Sanislav said until confirmation of the find near Paluma, there were only six locations in the world where metamorphic diamonds were known to exist, ranging in size from microscopic right down to nanoscopic. Dr Sanislav said he was drawn to investigate the presence of metamorphic diamonds in the Clarke River Fault due to the work of a former honours student, who found evidence suggesting the rocks there had potentially experienced high-pressure metamorphism. “This discovery will influence our understanding of the tectonic models and how the eastern coast of Australia formed,” he said. “We now need to follow through and see how extensive these deposits of metamorphic diamonds are and where else we can find them.” Metamorphic diamonds are formed in subduction zones when two land masses collide, causing the edge of one tectonic plate to descend below another and sink deep within the Earth’s interior. The process of metamorphism, which takes millions of years, generates a massive increase in pressure and temperature as rocks, once at the Earth’s surface, descend down to the earth’s mantle before coming back up in the form of metamorphic rocks containing the tiny diamonds. These diamonds differ from the more commonly recognised diamonds initially formed in the earth’s mantle, which are mined across the world for use in jewellery, such as engagement rings. Dr Sanislav said the team made use of a special Raman microscope to identify the diamonds, shooting a laser beam onto a rock sample which can then be used to determine the presence of minerals contained in a rock. “The light then gets scattered and each mineral has a characteristic response, which gets back to the detector,” he said. The research team involved Dr Sanislav, JCU PhD student Alexander Edgar, JCU Associate Dean of Research Professor Paul Dirks and University of Adelaide Associate Professor Dr Carl Spandler. IMAGES on this page: Photos taken from a microscope showing metamorphic diamonds in rocks collected from the Clarke River Fault. Diamonds are identified by the white arrows. Photos: Alexander Edgar

Australian-first metamorphic diamonds find

Industry Queensland

Related News

ActivEX consolidates REE exploration ground

$70m overhaul kicks off at Tarong North plant

Ballymore bonanza as gold strikes reach 99.8g/t

Get access to breaking mining news, now.