Oxidized sulfur-rich arc magmas formed porphyry Cu deposits by 1.88 Ga

A groundbreaking study reveals that porphyry copper deposits, typically associated with Phanerozoic arc magmas, were already present in the late Paleoproterozoic. Researchers analyzed the Haib porphyry Cu deposit in Namibia's Richtersveld Magmatic Arc, demonstrating that its 1.88-billion-year-old ore-forming magmas were highly oxidized and sulfur-rich, similar to modern deposits. This suggests that metallogenic processes operating today had already begun recycling sulfate-rich seawater or sediments from subducted oceanic lithosphere over 1.8 billion years ago.

Meng, X., Kleinsasser, J. M., Richards, J. P., Tapster, S. R., Jugo, P. J., Simon, A. C., Kontak, D. J., Robb, L., Bybee, G. M., Marsh, J. H., & Stern, R. A. (2021). Oxidized sulfur-rich arc magmas formed porphyry Cu deposits by 1.88 Ga. Nature Communications, 12(1). https://doi.org/10.1038/s41467-021-22349-z