Fingerprinting hydrothermal fluids in porphyry Cu deposits using K and Mg isotopes

In this study, we performed an integrated investigation of K and Mg isotopes in hydrothermally altered rocks from the giant Dexing porphyry Cu deposit in China. Both the altered porphyry intrusion and the surrounding wall rocks exhibit large variations in K and Mg isotope compositions, with δ41K values ranging between −1.0296‰ and 0.38‰, and δ26Mg values ranging between −0.49‰ and 0.32‰. The δ41K and δ26Mg values of the majority of altered...