GSA Connects 2021 in Portland, Oregon

Paper No. 68-3
Presentation Time: 8:40 AM


KREINER, Douglas, Alaska Science Center, U.S. Geological Survey, 4210 University Dr, Anchorage, AK 99508

Mineral systems provide a conceptual framework for relating deposits to their geologic and tectonic settings. A mineral system consists of five essential components: 1) an energy driver (topographic, thermal), 2) source of materials (metals), 3) transport media (magmatic, meteoric, metamorphic, or basinal fluids), 4) transport pathways (permeability), and 5) traps (physical or chemical). The components may occur across spatial scales ranging from a tectonic region (>1000 km) to a mineral deposit itself (<1-10 km) and timescales ranging from thousands to millions of years. More than one deposit type may form in a single mineral system, and single mineral systems can produce deposits that are broadly similar with locally distinct attributes. Multiple mineral systems may also occur in the same tectonic setting and may overlap in space. All these characteristics can influence the metallogenic and critical mineral signature of resulting deposits.

Mineral systems also provide a useful framework for predicting critical mineral enrichments and localization in deposits that host economically favorable commodities such as base and precious metals. A mineral systems framework helps to identify the key factors that might have influenced coproduct and byproduct critical mineral enrichments during deposit formation – factors important for metallurgic extraction and economics. These factors include the generation of magma; the source of metals, ligands and fluids; interactions among host lithologies, fluids, and magmas; evolution of magmas and fluids through time and space; and, ultimately, the types of traps. These features and processes influence metal enrichments, particularly trace and byproduct metals, in a deposit. Documenting and comparing the characteristics of mineral systems, associated deposits, and their tectonic setting leads to a better understanding of critical mineral enrichments, sources, sinks, transport mechanisms, localization, and fate. This framework can also be utilized to identify data gaps and prioritize new research in regions that have mineral systems favorable for critical minerals but otherwise remain incompletely mapped and understood.