Fluid inclusion composition reveals mineralization potential of the Mogutu skarn deposit, NE China

• The Mogutu fluids are enriched in Sn, Ag, Fe, and Zn-Pb, but depleted in Cu, W and Mo. • The fluid composition is consistent with the economic Sn-Ag-Fe-Zn but no Cu-Mo-W ores. • The workflow for evaluating the potential and scale of mineralization of various metals is given. • The fluid composition is useful in assessing mineralization potential and helpful in exploration. The growing global demand for mineral resources underscores the increasing importance of intrusion-related hydrothermal deposits as the major sources of numerous metals such as Cu, Mo, Sn, and W. While magmatic-hydrothermal systems are widespread, determining their ore-forming capability and establishing methods to assess their potential remain key challenges for mineral exploration. Ore-related fluids trapped in fluid inclusions at relatively high temperatures predating mineralization preserve the pristine geochemical signatures of magmatic exsolution, serving as an ideal tool for addressing the above issues. In this study, the fluid inclusions in the pegmatite quartz from an Early Cretaceous alkali-feldspar granite, the causative intrusion of the Mogutu skarn deposit in NE China, were analyzed using laser ablation-inductively coupled plasma-mass spectrometry. The results have been used to demonstrate how fluid compositions can be applied to evaluate the fertility of the hydrothermal system. The Mogutu fluids exhibit elevated concentrations of Sn (560 ppm) and Ag (78 ppm) compared to Sn- or Ag-barren systems, but are depleted in Cu (540 ppm) relative to typical Cu-mineralized systems. The concentrations of Fe (3.2 wt%), Zn (5,700 ppm), and Pb (2,950 ppm) are comparable to both those Fe/Zn-Pb deposits and barren systems. The results align with the occurrence of economic Sn-Ag ores in the Mogutu skarn, while the Fe mineralization likely benefited significantly from an additional contribution from the Fe-rich wallrocks (e.g., andesite). Mass balance calculation further reveals the high endowment of Zn-Pb but low W-Mo, consistent with the widespread Zn-Pb ores but no W-Mo mineralization in Mogutu and the surrounding region. This study demonstrates that fluid inclusion composition is a reliable geochemical indicator for assessing mineralization potential, thereby enhancing predictive accuracy in magmatic-hydrothermal prospectivity.