Metallogeny

Metallogeny is the branch of economic geology that studies the origin, distribution, and classification of metallic ore deposits within the crust, and their relationship to tectonics, magmatism, and sedimentary processes. The central aim is to understand how and when metals are sourced, transported, and precipitated to form accumulations that are economically exploitable.

Metallogeny examines the sources of ore metals (such as magmatic differentiation, hydrothermal fluids, and sedimentary systems), the pathways by which metals are moved in solution, and the physicochemical triggers that cause ore minerals to crystallize or precipitate. It also considers the structural and tectonic controls that create permeability and fluid flow, such as subduction zones, continental rifts, and orogenic belts. Isotopic dating and geochronology are used to establish timing relative to regional tectonics and magmatic events.

Deposits are grouped into metallogenic classes and belts, including magmatic-hydrothermal systems (for example porphyry copper and IOCG deposits), volcanogenic massive sulfide (VMS) deposits, sedimentary-exhalative (SEDEX) deposits, Mississippi Valley-type (MVT) lead-zinc deposits, and various sediment-hosted copper and nickel deposits, as well as placer and lateritic deposits. The study also addresses alteration halos, ore minerals (such as chalcopyrite, sphalerite, galena, magnetite, nickel sulfides, and native gold), and associated pathfinder elements and minerals.

Practical metallogeny informs mineral exploration by integrating geology, geochemistry, geophysics, and geochronology to identify prospective terranes, estimate resource potential, and constrain exploration risk. The field evolves with advances in imaging, isotopic techniques, and models linking metallogeny to plate tectonics.