The southern region of the South China Block hosts a super-large metallogenic province. However, the Mesozoic differential metallogeny between the southern Cathaysia Block (W-Sn) and the southern Yangtze Block (Au-Sb) remains enigmatic. To characterize the crustal architecture beneath different metallogeny belts, we integrate 3239 published ε_Hf(t) values of synmagmatic zircons from Mesozoic igneous rocks and corresponding whole-rock ε_Nd(t) datasets to generate coupled Hf–Nd isotopic mappings. The results show that ε_Hf(t) values range from −19.3 to +11.6 (T_DM2: 464–2419 Ma) and ε_Nd(t) values are from −12.2 to +5.0 (T_DM2: 580–2008 Ma) in the southern part of South China Block. High ε_Hf(t) (−4~+11.6) and ε_Nd(t) (−4~+5.0) zones are concentrated along the Honghe Fault and Chenzhou–Linwu Fault systems, while low-value Hf–Nd isotopic (ε_Hf(t) = −10.6 to −4; ε_Nd (t) = −12.2 to −4) zones are mainly distributed in the interior of the southern Yangtze Block. The W-Sn deposits in the southern Cathaysia Block are genetically linked to the heterogeneous ε_Hf(t)-ε_Nd(t) isotopic domains. The ore-forming materials of these high-temperature W-Sn polymetallic deposits may primarily derive from crust hybrid magmas that have undergone multistage crustal reworking. In contrast, low-temperature Au-Sb deposits in the northern Youjiang basin are distributed in areas characterized by elevated ε_Hf(t)-ε_Nd(t) isotopic signatures, which are primarily derived from reworked crust with significant mantle contributions. Most magmatic rock-associated Au deposits tend to cluster at the boundaries of Hf-Nd isotopic anomalies, which indicates the contribution of crust-mantle interaction to Au mineralization. Our Hf-Nd isotopic mappings reveal that mantle-crust deep-seated process controls the Mesozoic differential metallogeny between the southern Cathaysia Block (W-Sn) and the southern Yangtze Block (Au-Sb).

Fe-Mn carbonate is the dominant mineral in the Erdaokan Ag deposit, which represents the first large independent silver deposit during the Late Triassic Period in the Duobaoshan Cu-Mo-Au mineralization concentrated area of Heilongjiang Province, NE China. The Fe-Mn carbonates in the deposit frequently co-exist with Ag minerals. Thus, the presence of Fe-Mn carbonates plays a crucial role in the ore-formation process, making their analysis essential for obtaining valuable metallogenic information about the Erdaokan deposit. Through microexamination, SEM and EDS analysis, a clear relationship between Fe-Mn carbonate minerals and Ag minerals was established. Furthermore, electron probe microanalysis, LA-ICP-MS, and Sr-Nd isotope tests were conducted to analyze Fe-Mn carbonates for significant metallogenic insights. The distribution pattern of trace elements and rare-earth elements in Fe-Mn carbonates is similar, characterized by Zr depletion (below 0.131 ppm), enrichment of light rare-earth elements, a noticeable deficit of Eu (δEu = 0.06–0.63), and an average Y/Ho value of 34.29, indicating the involvement of upper mantle-derived deep magma in the formation of ore-forming materials. The samples had a Sm-Nd isochron age of 233.7 ± 1.2 Ma, suggesting that the Erdaokan Ag deposit was formed during the Late Triassic Period. This study highlights the significance of Fe-Mn carbonate as a valuable mineral indicator for regional silver prospecting purposes, and confirms the Late Triassic Period as another important metallogenic stage in the Duobaoshan Cu-Mo-Au mineralization concentrated area.

Hydrogen, as the smallest atom and a key component of water, can penetrate minerals in various forms (e.g., atoms, molecules), significantly influencing their properties. The hydrogen diffusion behavior in corundum (α-Al₂O₃) under high pressure was systematically investigated using the DFT + NEB method. The results indicate that H atoms tend to aggregate into H₂ molecules within corundum under both ambient and high-pressure conditions. However, hydrogen predominantly migrates in its atomic form (H) under both low- and high-pressure environments. The energy barriers for H and H₂ diffusion increase with pressure, and hydrogen diffusion weakens the chemical bonds nearby. Using the Arrhenius equation, we calculated the diffusion coefficient of H in corundum, which increases with temperature but decreases with pressure. On geological time scales, hydrogen diffusion is relatively slow, potentially resulting in a heterogeneous distribution of water in the lower mantle. These findings provide novel insights into hydrogen diffusion mechanisms in corundum under extreme conditions, with significant implications for hydrogen behavior in mantle minerals at high pressures.