Secular changes in the distribution and characteristics of mineral deposits ... - David Huston

Secular changes in the distribution and characteristics of mineral deposits – implications for the geodynamic and environment evolution of Earth
David Huston
Geoscience Australia

Since at least the 1970s economic geologists have known that the distribution of mineral deposits has not been uniform through time. The temporal distribution not only differs between deposit types, but within deposit types. The advent of new and more precise geochronology and the compilation of metallogenic data sets have enabled a much more precise documentation of these changes and a better understanding of how metallogenic changes relate to geodynamic and environment changes. This presentation presents an overview of secular changes in metallogenesis using deposits that form in different tectonic settings. For example, deposits that form along convergent margins – volcanic-hosted massive sulfide, porphyry copper, orogenic gold, intrusion-related rare metal and pegmatite – are associated with supercontinent/craton assembly and occur in a reasonably consistent sequence in metallogenic provinces. Similarly, although not as well known, deposits that form along divergent margins or in basins also have distinctive temporal distributions. Moreover, the temporal distribution and mineralogical and isotopic characteristics of some deposit types appear to change as a consequence of environmental changes such as the Great Oxidation Event. Metallogenic datasets provide another tool to understand how Earth has evolved geodynamically and environmentally through time.