Saturday, January 10, 2009

Deep sea vents

Te Deep sea vents are hydrothermal fissures which are present under the sea waters on ocean beds. Hydrothermal vents are locally very common because the earth is both geologically active and has large amounts of water on its surface and within its crust. Common land types include hot springs, fumaroles and geysers. The most famous hydrothermal vent system on land is probably within Yellowstone National Park in the United States. Under the sea, hydrothermal vents may form features called black smokers.


Photo: ocean-ridge.ldeo.columbia.edu

The most famous deep sea vents are probably the ones which are present in the Yellowstone National Park. These vents throw out superheated saline water which is not even suitable for any life forms. Also, these vents are located at depths where sunlight does not reach so the ecosystem that exists here is surviving completely without any sunlight. Bacteria are formed here which form the food of the slightly bigger organisms. Blind crabs and shrimps also exist at such levels.

Scientists first discovered undersea hot springs, known as hydrothermal vents, nearly 30 years ago. These vents, which are among the world's most extreme ecosystems, are found along the ocean ridge, 40,000 miles of underwater mountain range that zig-zags throughout the world's ocean basin. The vents spew super-hot, mineral-rich water that helps support exotic communities of animals and microbes. Issues surrounding research practices in vent areas have been sporadically discussed in the scientific literature since the late 1990s. Now, hydrothermal vents and the habitat they create are in the scientific, public, and political limelight as a result of improved technology that allows for greater studies of these remote areas.

The Mineral exploration companies, driven by the elevated price activity in the base metals sector during the mid 2000s, have turned their attention to extraction of mineral resources from hydrothermal fields on the seafloor. Significant cost reductions are, in theory, possible. Consider that in the case of the Mt Isa orebody, large amounts of capital are required to sink shafts and associated underground infrastructure, then laboriously drill and blast the ore, crush and process it, to win out the base metals, an activity which requires a large workforce.



Photo: science.psu.edu

A hydrothermal field, consisting of chimmneys and compacted chimmney remains, can be reached from the surface via a dynamically positioned ship, using conventional pipe, mined using modified soft rock mining technology, brought to the surface via the pipe, concentrated and dewatered then shipped directly to a smelter.

Deep sea vents are also known as deepwater seeps, deep-sea springs, and hydro-thermal vents. Found at the bottom of the ocean, they are created by volcanic and tectonic activity in areas where huge hostile plates are converging or spreading apart. Magma erupts along the margins of these plates, usually slowly, but sometimes with such ferocity that it creates instant lava lakes. The thick black smoke is actually a plume of metal-rich, superheated water billowing out of the silt- and sediment-covered, gray-and-black chimney-an underwater volcano.

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