Volcanoes source of life

Characteristics of a volcano

A volcano definition of volcanism, given by an American geologist: "It all physico-chemical phenomena which accompany the ascent of magma.  is composed of three parts: a reservoir of magma at depth, one or more volcanic vents that communicate with the interior of the Earth, and the volcanic mountain that is either a crater, a crater cone or dome or a lava flow or a deposit product explosion (layers of pumice, etc..).
Volcanic eruptions give rise to popular beliefs mingled terror and superstitious legends fantastic. It is true that some eruptions can be devastating to the point of disappearance of civilizations. A volcano is a highlight of the Earth's crust, (submarine or air) formed by the ejection and stacking of materials from the rise of magma as lava and tephras tephra represent all the materials ( solids and liquids, driven by gases) emitted by volcanoes, with the exception of the lava, they come from different types of explosive eruptions.  such as ash. A volcano is fed by one or more reservoirs of magma. This magma from partial melting of the mantle. It is through the flues or the molten rock reaches the surface and the accumulation of these rocks can reach thousands of meters thick forming the mountains and even islands. Depending on the materials, the type of eruption frequency and orogenesis, the volcanoes have different shapes, generally they are conical hills ending in a crater or caldera. The eruption comes out of the volcanic chimney usually located at the top, but sometimes openings occur on the flanks of the volcano as Mount Etna.
Volcanoes are classified into two types:
the "red volcanoes" to effusive eruptions relatively quiet, emitting lava fluids in the form of streams, are the volcanoes of "hot spot" volcanoes and submarine oceanic ridges; the "volcano gray explosive eruptions emit pasty lava and ash in the form of pyroclastic flows (or pyroclastic flows) and volcanic plumes.

There are about 1 500 active volcanoes on Earth which sixty erupt every year. The word "volcano" comes from Vulcano, one of the Aeolian Islands named in honor of Vulcan, the Roman god of fire. Its equivalent in the Greek pantheon is Hephaestus.
For the Romans, Vulcan is one of three son of Jupiter and Juno. Vulcan reigned supreme in the bowels of burning volcanoes. Therefore, it was taken as the patron of blacksmiths as legend said it had set up his forge in the depths of the crater, Vulcano.

Image: The red volcanoes, effusive eruptions are relatively quiet, emitting lava fluids in the form of streams, are the volcanoes of "hot spot".

Image: The gray volcanic eruptions explosive issue of pasty lava and ash in the form of pyroclastic flows and volcanic plumes.

The key to the origins of life

Image: Erta Alé google map

The volcanoes are probably the key to the origins of life on our planet Earth. In Ethiopia the land of Afar, is the smoking mountain, the volcano Erta Ale.
This volcano is one of the most surprising of the planet because it feeds a lake of molten lava permanent feature as rare among the 1,500 active volcanoes, Kilauea and only the Erebus contain a permanent lava lake. This is a representation of small-scale, time and space, the tectonics of lithospheric plates on our globe.
It allows us to see how under the pressure of the heat from the center of the Earth cooled plate, drifted down the lake to go back to the depths of the earth.
It is the image of continental drift on a human scale.
The result of the collision of these mini plates is the formation of small hills as it happens around the Earth. The creation of these plaques is the ground on which we live.

Image: The lava lake of Erta Ale

Image: The lava lake of Erta Ale. The Erta Ale is one of three volcanoes in the world, Kilauea and Erebus, to contain a permanent lava lake.

Earth saved from ice

The volcanoes have brought to the surface of the earth, heat, water and a potent cocktail of organic compounds (hydrogen sulfide, arsenic...) which are the origin of life. In fact, the primitive organisms have for 2 billion years, fed this soup, which scientists say is the volcanic lakes are one of the cradles of life possible. Volcanoes have not only sustained life but also protected to a distant time when the sun warming our planet much less than today. The intense release of CO2 (carbon dioxide) Volcanoes helped heat the Earth to settle permanently in our atmosphere. Thanks to the volcanic cataclysm that our planet was released from his frozen state sphere. Indeed there are about 600 million years, a period of intense ice hit the Earth, the glaciers were present everywhere, the polar caps down to the equator and covering the entire surface of the planet. Despite the ice down to the equator, volcanic activity continued to emit CO2 and methane (CH4) in the atmosphere. Volcanic eruptions have pierced the ice caps. When the concentration of methane and carbon dioxide was sufficient, the Greenhouse baited the collapse, freeing the Earth from its grip of ice.

After the glacial period called "snowball" was the big thaw with severe thunderstorms as the temperature rose in some areas of -50 ° C to +50 ° C in a few centuries. A phenomenal leap of biochemical diversity would occur from a handful of microbes that have survived.

Image: Gas emission of Krakatoa in 1997

Big Bang of the Life

The stromatolites (mats stone in Greek) are the first traces of life on Earth, the oldest discoveries in Australia, dating back 3.5 billion years. The solid stromatolitic columns are topped with a thin surface layer which is the living part, consisting of gelatin filaments of cyanobacteria, a kind of unicellular blue-green algae. After the long reign of these unicellular organisms, multicellular organisms appear complex, shapes and sizes. At this period there began 600 million years, is the Ediacaran fauna, soft-bodied organisms in the sandstones of the Precambrian Ediacara Hills in South Australia. This period starts the "Big Bang of life" is the explosion of complexity that will bring all agencies to keep pace with climate change. In this giant leap forward in life, volcanoes have played a large role in ending the ice age "snowball". The combination of volcanoes and the living world, especially the plankton of the oceans, has miraculously adjusted CO2 from the atmosphere.

In fact after rejecting huge amounts of carbon dioxide in the atmosphere and encouraged the explosion of life, plankton came absorb this CO2 and uses it today to form its shell, thus removing a large Part of carbon dioxide.

Image: Stromatolites on the west coast of Australia, the National Park Yalgorup.

Conclusion

The phenomenal amount of energy contained in the depths of the earth, trying to escape by any means possible volcanism and subduction allows that.
Volcanism and the Earth keeps running out of CO2 (carbon dioxide, greenhouse gas emissions) and cool, which would considerably slow down the evolution of life. The creation of the C02 was the cause of the explosion of life to bring the temperature of the Earth in an ideal range (15 ° C on average) where living organisms can develop their full biochemical energy.

Image: Etna. Carbon dioxide comes mainly from volcanic activity.

Image: Kilauea. Volcanoes emit huge quantities of CO2.