Its geology makes porphyry deposits rare, while most of the large near-surface examples have already been found. This means that understanding how and where they are formed can be of interest to mining companies looking for untapped resources.
This is particularly important given recent predictions that forecast an annual supply shortfall that could reach 10 million tonnes by 2030 if no mines are built.
According to the researchers, the link they found is related to the way in which large amounts of mineralizing fluids are extracted and transported from their source magmas and focused on the mineral-forming environment through “crystal slurry dikes.”
These levees “reconnaissance is paramount for the development of more reliable porphyry exploration models and is important for other mineral formation systems and volcanic processes,” said Lawrence Carter, lead author of the study, in a press release.
To arrive at these findings, the experts conducted field studies and micro-textural and geochemical analysis of samples from the archetypal Yerington porphyry district in Nevada, where a paleo-vertical cross-section of ~ 8 kilometers is exposed through various systems of copper porphyry deposits. .
There, the team was able to identify a network of quartz interconnected with worms within dikes found in rocks that were once beneath copper deposits. This represents paleoporosity in a once permeable mass of feldspar and quartz magmatic crystals. The slurry acted as conduits for large amounts of fluids forming porphyry deposits from deep portions of underlying magmas.
The group believes that this breakthrough may provide insights for the discovery of new copper porphyry deposits, which already provide 75% of the world’s copper, and the key proposed mechanism for the formation of other types of ore deposits, as well as the processes degassing in volcanic systems.