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Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth's crust through fractures. They eventually produce metallic -rich fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals.
Epithermal — mineral ore deposits formed at low temperatures (50–200 °C) near the Earth's surface (<1500 m), that fill veins, breccias, and stockworks. [2] Telethermal — mineral ore deposits formed at shallow depth and relatively low temperatures, with little or no wall-rock alteration, presumably far from the source of hydrothermal ...
Hydrothermal. A cross-section of a typical volcanogenic massive sulfide (VMS) ore deposit. Hydrothermal deposits are a large source of ore. They form as a result of the precipitation of dissolved ore constituents out of fluids. [1] [30] Mississippi Valley-Type (MVT) deposits precipitate from relatively cool, basal brinal fluids within carbonate ...
The ore fluids of MVT deposits are typically low temperature (100 °C–150 °C) and have the composition of basinal brines (10–30 wt.% NaCl equivalent) with pH's of 4.5–5 (buffered by host carbonates). This hydrothermal fluid may or may not carry the required sulfur to form sulfide minerals.
Most VMS deposits show metal zonation, caused by the changing physical and chemical environments of the circulating hydrothermal fluid. Ideally, this forms a core of massive pyrite and chalcopyrite around the throat of the vent system, with a halo of chalcopyrite-sphalerite-pyrite grading into a distal sphalerite-galena and galena-manganese and ...
Even if some deposits clearly indicate a magmatic source, it must be considered that only due to overprinting mineralization with higher gold grades from other sources, these deposits became economic. [23] A hybrid deposit with a combination of a magmatic and a metamorphic (mid- or sub-crustal) source is a much more common scenario. [24]
The dispersal of hydrothermal fluids throughout the global ocean at active vent sites creates hydrothermal plumes. Hydrothermal deposits are rocks and mineral ore deposits formed by the action of hydrothermal vents. Hydrothermal vents exist because the Earth is both geologically active and has large amounts of water on its surface and within ...
Paragenesis is a petrologic concept meaning an equilibrium sequence of mineral phases. [1] It is used in studies of igneous and metamorphic rock genesis and importantly in studies of the hydrothermal deposition of ore minerals and the rock alteration (vein metasomatism) associated with ore mineral deposits.