Quantitative analysis of crustal thickness evolution across past geological periods poses significant challenges but provides invaluable insights into the planet’s geological history. It may help uncover new areas with potential critical mineral deposits and reveal the impacts of crustal thickness and elevation changes on the development of the atmosphere, hydrosphere, and biosphere. However, a significant knowledge gap in reconstructing regional paleo-crustal thickness distribution is that most estimation proxies are limited to arc-related magmas. By mining extensive geochemical data from present-day subduction zones, collision orogenic belts, and non-subduction-related intraplate igneous rock samples worldwide, along with their corresponding Moho depths during magmatism, we have developed a machine learning-based mohometry linking geochemical data to Moho depth, which is universally applicable in reconstructing ancient orogenic systems’ paleo-crustal evolution and tracking complex tectonic histories in both spatial and temporal dimensions. Our novel mohometry model demonstrates robust performance, achieving an R² of 0.937 and RMSE of 4.3 km. Feature importance filtering highlights key geochemical proxies, allowing for accurate paleo-crustal thickness estimation even when many elements are missing. The mohometry validity is demonstrated through applications to southern Tibet, which has well-constrained paleo-crustal thicknesses, and the South China Block, which is noted for its complex tectonic evolution and extensive 800-km-wide Cretaceous extensional system. Additionally, the evolution of reconstructed paleo-crustal thickness, particularly in areas with anomalously thick crust, strongly correlates with porphyry ore deposits. These findings offer valuable insights for prospecting for new porphyry ore deposits, particularly in ancient orogens where significant surface erosion has occurred.

Studies on the Fe, Cu, and Zn isotopic compositions of volcanic rocks and sulfides provide an important tool for understanding magmatic, hydrothermal, and alteration processes. In this study, the δ56Fe and δ57Fe values of the MORBs are higher than those of the seafloor hydrothermal fluids, while the reverse is true for the δ66Zn and δ68Zn values, suggesting that basalt-fluid interactions preferentially incorporate isotopically light Fe and heavy Zn into the fluid, resulting in the relative enrichment of the heavier Fe and lighter Zn isotopes in altered basaltic rocks. Most of the δ56Fe values (–1.96 to +0.11‰) of the sulfide minerals are within the range of the vent fluids, but they are significantly lower than those of MORBs and back-arc basin basalts (BABBs), suggesting that the Fe in the sulfides was mainly derived from the fluids. However, the majority of the δ56Fe and δ57Fe values of chalcopyrite are larger than those of sphalerite and pyrite. This suggests that high-temperature sulfide minerals are enriched in 56Fe and 57Fe, whereas medium- and low-temperature sulfides are depleted in 56Fe and 57Fe. Moreover, the δ65Cu (–0.88 to –0.16‰) and δ66Zn (–0.39 to –0.03‰) values of the sulfide minerals are significantly lower than those of the MORBs, BABBs, and fluids, suggesting that 63Cu and 64Zn were preferentially removed from the fluids and incorporated into the chalcopyrite and sphalerite, respectively. Consequently, vent fluid injection and deposition can cause the heavier Cu and Zn isotopic compositions of hydrothermal plumes, seawater, and sediments.