An ultra-rare mineral named reidite has been found from what is possibly the world’s largest crater at Shark Bay in Western Australia.
The crater is only the sixth-known on Earth that holds the mineral.
Reidite starts as the common mineral zircon before transforming to reidite after an incredible pressure from space rocks slam into the Earth’s crust.
Curtin University research found that some zircon grains had partially turned to reidite, after observing drill core sampled from the middle of the buried Woodleigh impact crater – a region called the central uplift.
Aaron Cavosie, Curtin’s School of Earth and Planetary Sciences research supervisor, said, “Central uplifts are desirable targets for learning about impact conditions. They bring profoundly damaged rocks closer to the surface, and in some instances, are associated with exploration targets.
“Finding reidite at Woodleigh was quite a surprise as it is much rarer than diamonds or gold, though unfortunately not as valuable.”
Researchers were trying to discover the size of the Woodleigh impact crater, as it lies under younger sedimentary rocks and therefore remains unknown.
Previous research estimated the size to be between 60km and over 120km in diameter, but the research team suggested its finding of reidite near the base of the core indicated it may be larger.
Morgan Cox, lead author and Honour’s student from Curtin’s School of Earth and Planetary Sciences, said, “The research team is now using numerical modelling to refine the size of Woodleigh, and if we establish its diameter is greater than 100km, it would be the largest-known impact crater in Australia.”