Around the strangest volcano in the world: The origin of carbon lava is revealed

During the study of the world's most strange volcano, scientists discovered the underlying cause of the world's only carbon lava. New geological and chemical analyzes reveal that an extremely small proportion of typical minerals melting in the crust above the earth is the source of carbon lava erupting from the Oldoinyo Lengai volcano in Tanzania.

Although carbon lava - commonly known as carbonate - was found throughout history, the OLdoinyo Lengai volcano in the East African cracks in Northern Tanzania is the only place on this lava earth. still erupting. Lava erupting from volcanoes is very strange in that they contain almost no silica and contain up to 50% more carbonate (carbon dioxide) minerals. Common lava types contain high levels of silica, making their melting temperatures up to 900oC (equivalent to 1652oF). Oldoinyo Lengai volcanic lava erupts in the form of liquid at a temperature of approximately 540oC (1004oF). Low silica content is the cause of this ultra-liquid lava, like automobile oil when flowing .

A team of scientists from the University of New Mexico, Scripps Institution of Oceanography at UC San Diego and the Lava Research Center and the Chemical Composition of Minerals in Nancy, France reported the results of the spray study. Volcanic gas in an article in Nature published May 7.

David Hilton, a geochemical professor at Scripps Oceanography Institute at UC San Diego and co-author of the paper, said 'The chemical composition and isotopic composition of the gas shows that CO2 is directly derived. from the upper crust of the earth at the East African crack '. 'Surface gases allow us to speculate on the carbon composition of the upper crust producing carbonatities at a rate of 300/1000000 - an almost identical density with the density measured under the middle ridges. ocean heart '.

Mountains in the middle of the ocean are underwater mountains, where the sea floor spreads because the structures on the surface of the earth move apart. The valley valleys - for example in the area of the volcano Oldoinyo Lengai - and the mountains under the ocean are considered areas with different earth surface structures. However, this study also shows that their chemical composition is identical. This leads scientists to assume that their surface carbon content is not different but due to partial melting of typical minerals on the surface of the earth.

'Because volcanoes are in the pressure of magma (magma) during the eruption, we can collect primitive gas samples with the lowest level of air pollution', Tobias Fischier - volcanic researcher at the University of New Mexico said. New specimens obtained during the eruption in 2005 give scientists more insight into the process that takes place in the earth's upper crust.

Geo-chemical analyzes, some of which were performed at the Hilton geochemical laboratory of Scripps Institution of Oceanography, revealed that magma from the upper crust of both the ocean and continent are identical and a place of accumulation and mixing of volcanic gases such as Carbon dioxite (CO2), nitrogen, argon, and helium.

Lava erupting from volcanoes is very strange in that they contain almost no silica and contain up to 50% more carbonate (carbon dioxide) minerals. Common lava types contain high levels of silica, making their melting temperatures up to 900oC (equivalent to 1652oF). Oldoinyo Lengai volcanic lava erupts in liquid form at a temperature of approximately 540oC (equivalent to 1004oC). Low silica content is the cause of ultra-liquid lava, like automobile oil when flowing.

'These results are important because they show this strange type of lava and its precursor type - the niphelinites - created by melting a group of typical minerals on the surface without "It's a bit of carbon," said geochemist Bernard Marty of Nancy's Center for Lava Research and Chemical Composition. 'Rather, to create lava carbonate, all you need is a very low melting part of about 3% or less.'

Oldoinyo Lengai, like all other volcanoes, releases CO2 into the atmosphere. However, the magma of Lengai volcano is unusual because they contain high levels of sodium. About 1% of the carbon emitted from Lengai volcano is converted into carbonate, then melted with the rest, sprayed into the atmosphere as CO2. The CO2 emitted into volcanic atmospheres all over the earth is only a small percentage of the man-made amount.

References:
Fischer et al.Upper-mantle volatile chemistry at Oldoinyo Lengai volcano and the origin of carbonatites.Nature, 2009;459 (7243): 77 DOI: 10.1038 / nature07977