What would NOT be the expected origin of a mercury deposit?

• A. Hydrothermal veins
• B. Volcanic fumaroles
• C. Magmatic segregation
• D. Weathering

Answer: (D)

Mercury ore deposits form most commonly in high-temperature Fluid systems where mercury is transported and precipitated as cinnabar (HgS) in veins. Hydrothermal activity drives the movement of mercury-rich fluids through rock fractures, concentrating Hg as ore minerals in these vein systems. Volcanic fumaroles contribute mercury-bearing vapors that can condense and form Hg-rich deposits near volcanic regions, adding another primary pathway for accumulation. Magmatic segregation involves concentrating elements during magmatic differentiation, including mercury, which can produce sulfide-rich accumulations in some settings.

Weathering, on the other hand, is a surface/near-surface process that can release mercury from minerals into soils and water but does not typically create the concentrated ore bodies associated with mercury deposits. It disperses or mobilizes mercury rather than forming the thick, localized accumulations expected for ore deposits.