1.constructional materials :gravels ; sand;silt corals from continental shelf and beaches
2. placer deposits : come from land . These include diamonds off the coasts of South Africa and Namibia as well as deposits of tin, titanium and gold along the shores of Africa, Asia and South America.
3. petroleum and natural gas : on continental shelf when neritic deposits buried under terrigenious deposits.like mumbai high;kg delta;maracibo lake;persian gulf;gulf of mexico;around the caspian and black sea.;etc.
4. manganese nodules : . They are composed mainly of manganese, iron, silicates and hydroxides, and they grow around a crystalline nucleus .found below 4000m depth.mainly reserves in the greatest densities of nodules occur off the west coast of Mexico (in the ClarionClipperton Zone), in the Peru Basin, and the Indian Ocean. Manganese nodules are composed primarily of manganese and iron. The elements of economic interest, including cobalt, copper and nickel, are present in lower concentrations and make up a total of around 3.0 per cent by weight.and platinum or tellurium in trace form.
5. cobalt crust :Cobalt crusts form at depths of 1000 to 3000 metres on the flanks of submarine
volcanoes, and therefore usually occur in regions with high volcanic activity such as the territorial waters around the island states of the South Pacific. The crusts accumulate when manganese, iron and a wide array of trace metals dissolved in the water (cobalt, copper, nickel, and platinum) are deposited on the volcanic substrates
6.sulphide ores :Massive sulphides form at black smokers – hot springs on the sea floor with temperatures approaching 400 degrees Celsius. These vents discharge minerals from the Earth’s interior, forming chimneys that rise to several metres above the seabed. Black smokers are also unique habitats. the hydrothermal vents are the sources.While the black smokers along the East Pacific Rise and in the central Atlantic produce sulphides comprising predominantly iron rich sulphur compounds while sulphides ores occurrences in the southwest Pacific contain greater amounts of copper, zinc and gold. The largest known sulphide occurrence is located in the Red Sea, where tectonic forces are pulling Africa and the Arabian Peninsula apart. Here, the sulphides are not associated with black smokers, but appear in the form of iron rich ore muds with high contents of copper, zinc and gold. (at around 2000m depth.). . In May 2010 the ISA even has granted one exploration licence in the Indian Ocean to China. So far only permits for research have been granted for the deep sea. In the near future the mining of copper and gold from massive sulphides is likely to commence off the coasts of Papua New Guinea and New Zealand.
7. gas hydrates :>
Gas hydrate is a solid icelike form of water that contains gas molecules in its molecular cavities1. In nature, this gas is mostly methane. Methane gas hydrate is stable at the seafloor at water depths beneath about 500 m. The gas hydrate stability zone extends into the seafloor sediments down to a depth where temperature exceeds gas hydrate stability, usually some 10s to 100s of meters beneath the seafloor. At this depth, thin methane gas layers are often present causing strong reflections in seismic records. .as hydrates are naturally occuring, crystalline, ice like substances composed of gas molecules (methane, ethane, propane, etc.) held in a cage like ice structure. (clathrate).
The formation and stability in the subsurface of these structures are constrained by a relatively narrow range of high pressure and low temperature and depend on the influx of free gas and the amount of gas dissolved in the pore fluid.
Hydrates are a concentrated form of natural gas compared with compressed gas, but less concentrated
than liquefied natural gas. It is estimated that a significant part of the Earth's fossil fuel is stored as gas hydrates, but as yet there is no agreement as to how large these reserves are.
Where are they Found?
They are found abundantly worldwide in the top few hundred meters of sediment beneath continental
margins at water depths between a few hundred and a few thousand feet. They are present to a lesser
extent in permafrost sediments in Arctic areas.
In the marine environment the gas hydrate stability zone is determined by water depth, seafloor
temperature, pore pressure, thermal gradient and the gas and fluid composition. The base of the zone in which hydrate can exist is limited by the increase in temperature with depth beneath the seabed.
in india The Ministry of Petroleum and Natural Gas (MoPNG) has formulated the National Gas Hydrate Programme (NGHP) in 2000. NGHP Expedition01 launched in 2006, had established presence of gas hydrates in KG and Mahanadi basins and Andaman deep waters. NGHP Expedition02 and 03 are under advanced stage of planning and are due in the period 20142017.
last year in sept 2014 signed a treaty indous mou on gas hydrates.
Worldwide work on gas hydrates is at a research and development stage and no commercial exploitation has so far been reported. Gas hydrate resources in India are estimated at 1894 TCM and these deposits occur in Western, Eastern and Andaman offshore areas.
2. placer deposits : come from land . These include diamonds off the coasts of South Africa and Namibia as well as deposits of tin, titanium and gold along the shores of Africa, Asia and South America.
3. petroleum and natural gas : on continental shelf when neritic deposits buried under terrigenious deposits.like mumbai high;kg delta;maracibo lake;persian gulf;gulf of mexico;around the caspian and black sea.;etc.
4. manganese nodules : . They are composed mainly of manganese, iron, silicates and hydroxides, and they grow around a crystalline nucleus .found below 4000m depth.mainly reserves in the greatest densities of nodules occur off the west coast of Mexico (in the ClarionClipperton Zone), in the Peru Basin, and the Indian Ocean. Manganese nodules are composed primarily of manganese and iron. The elements of economic interest, including cobalt, copper and nickel, are present in lower concentrations and make up a total of around 3.0 per cent by weight.and platinum or tellurium in trace form.
5. cobalt crust :Cobalt crusts form at depths of 1000 to 3000 metres on the flanks of submarine
volcanoes, and therefore usually occur in regions with high volcanic activity such as the territorial waters around the island states of the South Pacific. The crusts accumulate when manganese, iron and a wide array of trace metals dissolved in the water (cobalt, copper, nickel, and platinum) are deposited on the volcanic substrates
6.sulphide ores :Massive sulphides form at black smokers – hot springs on the sea floor with temperatures approaching 400 degrees Celsius. These vents discharge minerals from the Earth’s interior, forming chimneys that rise to several metres above the seabed. Black smokers are also unique habitats. the hydrothermal vents are the sources.While the black smokers along the East Pacific Rise and in the central Atlantic produce sulphides comprising predominantly iron rich sulphur compounds while sulphides ores occurrences in the southwest Pacific contain greater amounts of copper, zinc and gold. The largest known sulphide occurrence is located in the Red Sea, where tectonic forces are pulling Africa and the Arabian Peninsula apart. Here, the sulphides are not associated with black smokers, but appear in the form of iron rich ore muds with high contents of copper, zinc and gold. (at around 2000m depth.). . In May 2010 the ISA even has granted one exploration licence in the Indian Ocean to China. So far only permits for research have been granted for the deep sea. In the near future the mining of copper and gold from massive sulphides is likely to commence off the coasts of Papua New Guinea and New Zealand.
7. gas hydrates :>
Gas hydrate is a solid icelike form of water that contains gas molecules in its molecular cavities1. In nature, this gas is mostly methane. Methane gas hydrate is stable at the seafloor at water depths beneath about 500 m. The gas hydrate stability zone extends into the seafloor sediments down to a depth where temperature exceeds gas hydrate stability, usually some 10s to 100s of meters beneath the seafloor. At this depth, thin methane gas layers are often present causing strong reflections in seismic records. .as hydrates are naturally occuring, crystalline, ice like substances composed of gas molecules (methane, ethane, propane, etc.) held in a cage like ice structure. (clathrate).
The formation and stability in the subsurface of these structures are constrained by a relatively narrow range of high pressure and low temperature and depend on the influx of free gas and the amount of gas dissolved in the pore fluid.
Hydrates are a concentrated form of natural gas compared with compressed gas, but less concentrated
than liquefied natural gas. It is estimated that a significant part of the Earth's fossil fuel is stored as gas hydrates, but as yet there is no agreement as to how large these reserves are.
Where are they Found?
They are found abundantly worldwide in the top few hundred meters of sediment beneath continental
margins at water depths between a few hundred and a few thousand feet. They are present to a lesser
extent in permafrost sediments in Arctic areas.
In the marine environment the gas hydrate stability zone is determined by water depth, seafloor
temperature, pore pressure, thermal gradient and the gas and fluid composition. The base of the zone in which hydrate can exist is limited by the increase in temperature with depth beneath the seabed.
in india The Ministry of Petroleum and Natural Gas (MoPNG) has formulated the National Gas Hydrate Programme (NGHP) in 2000. NGHP Expedition01 launched in 2006, had established presence of gas hydrates in KG and Mahanadi basins and Andaman deep waters. NGHP Expedition02 and 03 are under advanced stage of planning and are due in the period 20142017.
last year in sept 2014 signed a treaty indous mou on gas hydrates.
Worldwide work on gas hydrates is at a research and development stage and no commercial exploitation has so far been reported. Gas hydrate resources in India are estimated at 1894 TCM and these deposits occur in Western, Eastern and Andaman offshore areas.
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