Fig. 5 Schematic distribution of hydrothermal alteration associated with LS and HS epithermal deposits; ore is located in paleoconduits. Beneath the epithermal environment, a degassing magma body contributes heat, water, acidic gases, and ore metals. In LS systems, the magmatic component equilibrates with wall rocks at depth during meteoric-water dominated convection, before ascent to epithermal depths. In HS systems, magmatic volatiles ascend to the epithermal environment with little modification, then are absorbed by meteoric water to form an acidic hypogene fluid that leaches wallrock outward from conduits. Ore metals are commonly introduced by late-stage magmatic-meteoric water mixtures.