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Porphyry-type ore deposits form in hydrothermal fluid circulation systems developed above and around high-level, subvolcanic felsic to intermediate magma chambers and/or cooling plutons. The ore is temporally and genetically related to the intrusions, but did not precipitate directly from the magma. [1]
Classification of hydrothermal ore deposits is also achieved by classifying according to the temperature of formation, which roughly also correlates with particular mineralising fluids, mineral associations and structural styles. [2] This scheme, proposed by Waldemar Lindgren (1933) classified hydrothermal deposits as follows: [2]
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]
Main ore minerals in SEDEX deposits are fine-grained sphalerite and galena, chalcopyrite is significant in some deposits; silver-bearing sulfosalts are frequent minor constituents; pyrite is always present and can be a minor component or the dominant sulfide, as it is the case in massive sulfide bodies; barite content is common to absent ...
Volcanogenic massive sulfide ore deposits, also known as VMS ore deposits, are a type of metal sulfide ore deposit, mainly copper-zinc which are associated with and produced by volcanic-associated hydrothermal vents in submarine environments. [2] [3] [4] These deposits are also sometimes called volcanic-hosted massive sulfide (VHMS) deposits.
Primary deposits contain hydrothermal and igneous processes while secondary deposits are sedimentary and weathering processes. [11] In the case of primary deposits, the minerals and metals are derived from a specific area, where the elements come together to form the deposit. [12] This location is also where the mineral is produced. [12]
In geology, mineralization is the deposition of economically important metals in the formation of ore bodies or "lodes" by various process. The first scientific studies of this process took place in the English county of Cornwall by J.W.Henwood FRS and later by R.W. Fox, FRS. [1]
Rarer types of hydrothermal fluids may include highly carbonic fluids, resulting in advanced carbonation reactions of the host rock typical of calc-silicates, and silica-hematite fluids resulting in production of jasperoids, manto ore deposits and pervasive zones of silicification, typically in dolomite strata. Stressed minerals and country ...