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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. In some occurrences, minerals can be extracted ...
These deposits are also sometimes called volcanic-hosted massive sulfide (VHMS) deposits. The density generally is 4500 kg/m 3 . They are predominantly stratiform accumulations of sulfide minerals that precipitate from hydrothermal fluids on or below the seafloor in a wide range of ancient and modern geological settings.
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 ...
Massive sulfide deposits are ore deposits that have significant stratiform ore bodies consisting mainly of sulfide minerals.Most massive sulfide ore deposits have other portions that are not massive, including stringer or feeder zones beneath the massive parts that mostly consist of crosscutting veins and veinlets of sulfides in a matrix of pervasively altered host rock and gangue.
Sphalerite is a sulfide mineral with the chemical formula (Zn, Fe)S. [5] It is the most important ore of zinc.Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits.
Eventually a point is reached where the minerals start to crystallise out. [2] Minerals formed in this way are called primary, or hypogene, minerals. Sulfur is a common component of the fluids, and most of the common ore metals, lead, zinc, copper, silver, molybdenum and mercury, occur chiefly as sulfide and sulfosalt minerals. [3]
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.
Mineral associations may vary (1) in different mineralized structures, either syngenetic (namely, passive precipitation in chimneys, mounds and stratiform deposits) or epigenetic (structures that correspond to feeder channels, and replacements of host rocks or pre-existing massive sulfide bodies), or structural zonation, (2) from proximal to ...