What (probably) controls the size of mineral deposits

Theoretical, conceptual, technical, and analytical advances over the last century have allowed not only to develop and refine models for the formation of mineral deposits, but also to develop cost-effective exploration methods to identify new deposits. However, once a new orebody is identified, it requires extensive drilling campaigns and massive investments to quantify its metal content. This is associated with increasing economic risks and social and environmental impacts, that are magnified by the current need to search for increasingly deeper orebodies (under cover). In order to mitigate such risks, it would advantageous to be able to determine (even coarsely) the size of the newly discovered deposit as early as possible during exploration.

While commonly advocated magmatic, hydrothermal and geochemical processes and their associated fertility indicators may indeed pinpoint toward the formation of a deposits, they fall short in explaining their ranges in metal endowment which typically cover over four to five orders of magnitude in each deposit type (e.g. porphyry copper deposits, MVT deposits). Here we discuss how understudied physical factors in porphyry copper and MVT deposits (such as fluid flow duration, magma intrusive flux and timescales in tandem with the thermo-mechanical conditioning of the crust) contribute on the fertility of such systems. Further we will explore possible ways to assess this ‘physical fertility’ from the rock record by combining cutting edge analytical methods and advanced numerical models.