HGCTM-S: Modeling Regional Lithology-Associated Mineral Assemblage Modes in Global Copper Deposits

Mineral assemblage records in global copper deposit databases contain information about ore-forming environments and geological context, but analysis is complicated by sparse observations, variable data quality, unequal documentation and overlapping mineralogical signals. Here, we introduce a hierarchical geological context topic model with sparse deviations (HGCTM-S). This model represents global copper deposits through context-conditioned assemblage modes and estimates deposit-level topic attribution by combining geological context with observed mineral-family records. Applied to 1335 deposits from the global copper deposit dataset, with 1205 mineral species grouped into 35 geologically defined families, the model recovered seven modes derived from the dataset. Independent comparison with deposit type labels most strongly supported a Cu–Mo mixed mode enriched in porphyry deposits and a Ni–Co–As mode enriched in magmatic-sulfide deposits; the other modes represented shared sulfide backgrounds, secondary overprints or residual components rather than direct genetic classes. Within the fitted topic-composition component, regional lithology-associated effective deviations were larger than broad age-associated deviations across alternative priors and lithology proxies, although the magnitude varied, and the proxies did not reliably reproduce deposit scale or hosts. Progressive initialization improved aggregate topic stability, but geographic performance was heterogeneous and did not generally exceed a baseline using geological context alone. Therefore, the HGCTM-S provides a way to compare overlapping mineral assemblage components and their regional geological associations rather than a universal classifier or regional predictor.