Understanding How Porphyry-Type Copper Deposits Form May Lead to New Resources – Study

Their 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 form can be of interest to mining companies looking for untapped resources.

This is particularly important given recent forecasts which predict 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 how vast amounts of mineralizing fluids are extracted and transported from their source magmas and concentrated in the ore-forming environment through “ pulp dykes of crystal ”.

These dikes “recognition is paramount for the development of more reliable porphyry exploration models and has significance for other ore formation systems and volcanic processes,” said Lawrence Carter, lead author of the study, in a report. Press release.

To achieve these results, the experts conducted field studies and micro-textural and geochemical analyzes of samples from the archetypal porphyry district of Yerington in Nevada, where a paleo-vertical cross section of about 8 kilometers to through a number of systems of porphyry copper deposits is exposed. .

There, the team was able to identify an interconnected network of worm-eaten quartz in dykes found in rocks that once lay beneath copper deposits. This represents paleoporosity in a once-permeable magmatic crystalline slurry of feldspar and quartz. The slurry acted as conduits for large amounts of fluids forming porphyry deposits from deep parts of the underlying magmas.

The group believes that this breakthrough could provide information for the discovery of new porphyry copper deposits, which already provide 75% of the world’s copper, and the proposed key mechanism for the formation of other types of ore deposits as well as for the processes. degassing in volcanic systems.