On the third day of proEXPLO 2021, this keynote speech was given by Dr. Jon Hronsky, who is currently Director of Western Mining Services (WMS), a consulting group that provides strategic level services to a wide variety of groups (from junior to major) throughout the global mineral exploration industry.

In his presentation "An integrated model for Cu and Au mineralization at convergent margins: two fundamental processes interacting in variable geodynamic situations", the specialist commented on the Loucks process and the FUME process, which stands for Fertile Upper Mantle Extraction.

Thus, according to Jon Hronsky, convergent margin orogens, such as the Andes, show a complex range of copper (Cu) and gold (Au) ore types; and while there are often clear links between Cu and Au metallogeny, there are also scenarios where these deposits occur separately.

"Recent advances indicate that two fundamental processes act to form ore deposits at convergent margins. These are the Loucks process, which is related to anomalous high-pressure fractionation of hydrated magmatic arcs that generates Cu metallogeny, and the FUME (Fertile Upper Mantle Extraction) process that generates Au metallogeny," he commented.

He added that both processes occur in response to anomalous geodynamic conditions on a regional scale. In some cases, these conditions favor only one of the two processes, while in other cases, both processes are favored simultaneously.