Kola Superdeep boreholeIt is quite hard to imagine that under this metal cap is actually the world d

Kola Superdeep boreholeIt is quite hard to imagine that under this metal cap is actually the world deepest borehole! In 1970 the Soviets started drilling the Kola Superdeep Borehole (Russian: Кольская сверхглубокая скважина) on the Kola peninsula of northern Russia. In 1989 the deepest point was reached at 12,262m. In comparison the deepest part of the ocean, the Mariana trench is 10,911m deep and the continental crust is around 35km thick.So, why did they stop drilling? Well, temperatures at 12,262m were much higher than expected. Instead of the expected 100 °C it was 180 °C, they calculated that at a depth of 15,000m (the depth they were expected to reach in 1993) temperatures would be 300°C. In addition, the pressure at these depths would have been too much for the drill to handle.Since the purpose of the borehole was to understand the nature of the earth’s crust, some interesting facts came to the surface. Scientists expected to find the so-called boundary of granite to basalt at 4-9km depth. What they found however was a fractured area that had been thoroughly saturated with water, which is remarkable at this depth. Also, fossils were found at depths of 6,7km and rather than covered in typical limestone and silica covering these had a carbon or nitrogen covering. The oldest rocks they hit were more than 2,5 billion years old.Lotte Geeven a Dutch artist, has actually partnered up with the geologists and engineers of another superdeep borehole, the German Continental Deep Drilling Program, to discover what it sounds like at these extreme depth in the earth’s crust (you can hear it here: http://wrd.cm/1nnNic3)In 1989 a Finnish newspaper, Ammenusastian, supposedly reported that a special microphone designed to detect tectonic plate movement was lowered down and recorded the cries of damned souls. Thus, this was seen (by certain Christian groups) as evidence that the Russians were drilling through the gates of hell..Since 2008 Kola is not the longest borehole anymore. First Qatar’s Al Shaheen oil well reached a length of 12,289m and in 2011 the Russians (again) managed to drill offshore the island of Sakhalin to a length of 12,345m. The differences are not that big.-OW-Image: Courtesy of Rakot14. This is actually the Kola Superdeep borehole. It was welded shut in 2005. Since 2008 the site has been abandoned.References and further reading:http://hypertextbook.com/facts/2003/AdamCassino.shtmlhttp://www2.gi.alaska.edu/ScienceForum/ASF7/725.htmlhttp://www.slate.com/blogs/atlas_obscura/2014/05/08/kola_superdeep_borehole_is_the_world_s_deepest_hole.htmlhttp://wrd.cm/1nnNic3 -- source link

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