Three researchers from James Cook University have found metamorphic diamonds in rocks close to Australia’s northeast coast, working with a colleague from the University of Adelaide. In their study, which was printed in the journal Science Advances, authors Alexander Edgar, Ioan Sanislav, Paul Dirks, and Carl Spandler describe how they found the tiny diamonds. They also give reasons for their belief that the discovery will help illuminate the formation and early history of Australia.
Only sporadically and in very specific places do metamorphosed diamonds form. They come in a variety of sizes, from microscopic to nanoscale. In subduction zones, where opposing plates grind against one another under pressure over millions of years, the rare diamonds are created. These diamonds are so small that they cannot be seen with the naked eye.
They have only ever been found on Earth in six other places. The majority of them were found by the researchers in their present examination at the Clarke River Fault, which was created 500 million years ago when crustal blocks were squeezed together.
The researchers began probing the rocks near the fault line after one of their students remarked some rock formations they had observed that appeared to have been exposed when one of the tectonic plates pushed them above the surrounding ground.
The researchers claim that the diamonds they observed were the first ones to be found in the Gondwana-Pacific region of the Terra Australis Orogen. Additionally, they assert that since metamorphic diamonds can only be made under extremely precise circumstances, research into them and the places where they are found may help uncover additional details about how Australia was formed.