120-17 Development of Consistent Geochemical Signatures for Mineral Deposits using Critical Minerals in Ore (CMiO) Dataset

Abstract:

Many mineral commodities presently defined as “critical” were not targeted in past mining operations and often are not the primary target for existing or new mines. Instead, most were byproducts or coproducts or were discarded in waste. Deposit model geochemical signatures could help anticipate additional extraction targets or byproducts opportunities but comprehensive geochemical signatures that identify enrichments of target elements, critical minerals, and other non-target elements are lacking. The Critical Minerals in Ore (CMiO) dataset provides the opportunity to develop comprehensive geochemical signatures. Using this dataset and a consistent and reproducible approach, we developed lists of typically anomalous elements in ores of a specific deposit type. Two criteria for anomalous concentrations, five- and ten-times average crustal abundance, were set as thresholds and represent moderately and highly anomalous concentrations, respectively. Each element was evaluated individually. Commonality was established first for each unique deposit and then for the deposit type. If 50 percent or more of the samples from a unique deposit exceeded the thresholds for a given element, the element was flagged as “anomalous” in that deposit. If 50 percent or more of the unique deposits of a specific deposit type were flagged as anomalous for an element, the element was flagged as “anomalous” for the deposit type.  Lists of moderately and highly anomalous elements were generated for all 112 deposit types in the CMiO database. Lists of elements with no analysis in any unique deposit of a given deposit type and those with data censored at reporting limits above the thresholds were also captured. This was done to differentiate these elements from those that truly did not meet the thresholds. Ag, Sb, As, Te, and Bi are the critical minerals most frequently included as highly anomalous for the CMiO deposit types. Os, Rh, Ru, and Ir are the critical minerals most frequently lacking any information for a deposit type, reflecting their sparsity of coverage in the dataset. For volcanogenic massive sulfide deposits, comparison of the lists of highly anomalous elements to published geochemical signatures highlight difficulties resulting from differing nomenclature, the expansiveness of the lists, and the ambiguity of approach. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 5, 2026

doi: 10.1130/abs/2026AM-21570

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