Geodynamic settings of mineral deposit systems

Abstract

Mineral deposits represent extraordinary metal concentrations that form by magmatic, magmatic–hydrothermal or hydrothermal processes in geodynamic environments typified by anomalously high thermal and/or mechanical energy near plate boundaries. As they require the conjunction of specific environmental conditions to form, particular mineral deposit types tend to occupy specific geodynamic niches. The temporal distributions of mineral deposit types reflect both formational and preservational processes. In the Archaean and Palaeoproterozoic, these were linked because of preservation in continental crust connected to thick buoyant subcontinental lithospheric mantle (SCLM), but were decoupled by the Neoproterozoic and Phanerozoic as a result of evolution to thinner, increasingly dense SCLM. The transition marks a change from mantle plume-influenced plate tectonics to modern-style plate tectonics, with broadly coincident environmental changes and a major impact on the nature and abundance of preserved mineral deposit types. As mineral deposits represent an integral part of tectonic process, they are essential indicators of that process and geodynamic settings, and should be incorporated into any holistic tectonic terrane analysis. Their distribution also provides a particularly critical test on ancient continental reconstructions derived from palaeomagnetic data. Conversely, such reconstructions provide a first-order targeting tool for the conceptual exploration required to discover new mineral provinces and deposits under cover.