Volcanic Metallogeny
How volcanism builds the world's ore deposits. Most of the metal we mine was concentrated by magmatic and hydrothermal processes tied to volcanism — and the tectonic setting of a volcano predicts which kind of deposit can form near it. This page explains those volcano→metal links in detail, and maps every Holocene volcano on Earth tagged by the deposit style its setting favours. It is geological context for exploration — not a hazard or eruption-risk product.
🌋 The volcano → metal connection
Each deposit family forms in a specific magmatic plumbing system. The metals, the depth, the host and the tell-tale alteration are all set by how and where the magma rises.
Porphyry Cu-Mo-Au
The planet's main copper source. Large, hydrous arc magmas stall as a pluton; as they cool, magmatic-hydrothermal fluids exsolve and deposit metals in dense stockwork veinlets over the cupola. Huge tonnage, low grade, concentric alteration (potassic → phyllic → argillic → propylitic).
Continental & oceanic subduction arcs.
Epithermal Au-Ag (HS / LS)
Shallow (<1.5 km) hot-spring systems above arc volcanism. High-sulfidation = acidic magmatic fluids → vuggy silica + alunite. Low-sulfidation = neutral, meteoric-dominated → adularia-sericite + banded quartz veins. Bonanza gold grades possible.
Subaerial felsic–intermediate arc volcanoes & calderas.
VMS — volcanogenic massive sulfide
Sulfides precipitated on or just below the seafloor at submarine volcanic centres — fossil "black smokers". Kuroko-type form in felsic island-arc/back-arc settings; Cyprus-type in ophiolitic (oceanic-crust) settings.
Submarine arcs, back-arcs & spreading ridges.
Skarn
Where an arc intrusion bakes and replaces carbonate wall-rock, building calc-silicate skarns charged with metal. Often flanks porphyry systems.
Arc intrusions cutting limestone/dolomite.
Alkaline complex / carbonatite
Deep, CO₂-rich alkaline magmas rising along continental rifts crystallise carbonatites and alkaline complexes — the world's premier source of rare-earth elements and niobium.
Continental rift / intraplate magmatism.
Greenstone-hosted & komatiite (ancient)
Archean–Proterozoic greenstone belts — ancient submarine volcanic piles — host the great orogenic gold camps (gold remobilised into shear-hosted quartz veins) and komatiite-hosted nickel. Not Holocene, so not on the live map — but it is the setting of much of GeaSpirit's second-chance gold (e.g. Marvel Loch), and where buried impact structures like Ora Banda can further focus metal.
Archean greenstone belts (Yilgarn, Abitibi, Barberton).
🗺️ World volcano map — tagged by deposit style
Every Holocene volcano (Smithsonian GVP), coloured by the ore-deposit style its tectonic setting favours. Click a volcano for its setting, rock type and metallogenic potential. Click a legend chip to filter.
Volcano data: Smithsonian Institution, Global Volcanism Program (GVP) — Holocene Volcano List (open data). Deposit-style tags are GeaSpirit's interpretation of tectonic setting and are indicative geological context, not a resource or discovery claim. Metallogenic models summarised from standard economic-geology literature.