Hydrothermal vent deposits deposition process

Hydrothermal vent deposits are thus a renewable source of metals and a record of the physical, chemical, biological, and geological processes at modern and ancient submarine vents. 

Shanks W. C., Ill (2001) Stable isotopes in seafloor hydrothermal systems vent fluids, hydrothermal deposits, hydrothermal alteration, and microbial processes. In Stable Isotope Geochemistry, Rev. Mineral. Geochem. 43 (eds. J. W. Valley and D. R. Cole). Mineralogical Society of America, pp. 469 -525. 

Mills, R.A. (1995) Hydrothermal deposits and metalliferous sediments from TAG, 26°N Mid-Atlantic Ridge, in Hydrothermal Vents and Processes (eds L.M. Parson, C.L. Walker and D.R. Dixon), Geological Society Special Publication No. 87, pp. 121-132. 

Alteration due to reactions between basalt and hydrothermal solution ( ambient seawater) below the seafloor in massive sulfide ore deposits has been studied extensively, and the physical relationship of a hydrothermal flow zone to such deposits is understood in general terms (13). However, the potential influence of chemical reactions in such stockwork zones on venting solutions and processes of massive sulfide deposit formation has been largely unrecognized. In examining affects on sulfur isotopic composition of the hydrothermal solution, the components of such reactions which may result in sulfate reduction are of primary interest. 

Vent fluids, hydrothermal deposits, hydrothermal alteration, and microbial processes... 

Modem hydro- High-temperature hydrothermal vents currently active at mid-ocean ridges offer a thermal mineral- unique opportunity to study a hydrothermal mineral deposit in the process of ization at formation. The current working model assumes that cold seawater sulphate is mid-ocean ridges drawn down into sea-floor basalts, where it is heated in the vicinity of a magma chamber. Some sulphate is precipitated as anhydrite whilst the remainder is reduced to sulphide by reaction with the basalt. The fluid is vented back onto the seafloor at about 350 C laden with sulphides. On mixing with seawater these are precipitated onto the sea floor as a fine sulphide sediment whilst at the vent site itself the sulphides are built into a chimney a metre or so in height. 

For a correct idea of the physicochemical conditions of accumulation of iron-ore sediments, an analysis of the forms of transport and conditions of deposition of iron and silica in recent active volcanic regions is necessary. Such an analysis should include establishing possible sources of the ore material (vents of active volcanoes, fumaroles, hydrothermal volcanic waters), the character and intensity of the process of migration and forms of transport of the ore components, and the conditions of deposition of the ore components in the course of their migration to the sea basin and when the river waters mingle with sea. waters. 

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