Advertisement

Nature

Journeying to the Earth’s core

Generic Avatar

Elise Andrew

CEO and Founder

clockOct 22 2013, 18:04 UTC
39 Journeying to the Earth’s core
derivative work by Anasofiapaixao

Is it possible to journey to Earth’s core like in the movie ‘The Core’? Back in the 1960’s, the USSR and the USA both believed it was not only possible to drill to the core; they had a race to see which country could get there first. While most of the media attention was on the Space Race, there was also the American project dubbed Project Mohole, which began in 1957 but was abandoned in 1966 because of lack of funding. The USSR’s project culminated in the Kola Superdeep Drillhole, which is the deepest hole ever drilled and the deepest artificial point at 12.262 km deep.

Advertisement

The Kola drilling project began in 1962 with drilling commencing in 1970. The technology for mining at such depths was not available then or now; therefore the Russians devised an innovation where instead of turning the drill bit by rotating the stem, only the drill bit at the end was rotated. This was achieved by forcing the drilling mud through the drill bit. The drill was halted in 1994, after 24 years of chewing through the Earth.

Some of the discoveries from the drill hole: 

  • the expected transition from granite to basalt at 3-6km below the surface was not there – instead there was metamorphic rock
  • microscopic fossils were found as deep as 6.7km below the surface in rocks more than 2 billion years old – 24 distinct species of plankton, with coverings of carbon and nitrogen rather than limestone or silica
  • the temperature rose quickly as the borehole deepened – at 12km the temperature reached 180°C
  • the last of the cores taken from the borehole were dated at 2.7 billion years old

The Kola Superdeep Drillhole was also subject to urban legends. Circulated originally in the early 1990’s, the legend was that a team of Russian scientists led by a "Mr. Azzacov" in an unnamed place in Siberia had drilled a hole that was nine miles (14.5 km) deep before breaking through to a cavity. When the drilling team lowered an extremely heat tolerant microphone and sensory equipment into the well, the temperature was 2,000 °F (1,100 °C); heat that allegedly came from a chamber of fire from which the tormented screams of the damned could be heard. The recording was later revealed to have been a remixed portion of the soundtrack of the 1972 movie Baron Blood and had a variety of other effects added. The full debunking is available on Snopes.

The movie ‘The Core’ had a group of people journeying to the centre of the Earth. Though the movie was a little fanciful, it had a consultant geologist who wrote an article for Nature about the plausibility of reaching the Earth’s Core.  He proposed that a small communication probe (about the size of a grapefruit) would be conveyed in a huge volume of liquid-iron alloy migrating down to the core along a crack blasted in the planet’s surface, with the metal closing up the hole behind the machine. This crack would need to be about 30 centimeters wide, several hundred meters long and several hundred meters deep to start with. To create this crack, the energy needed would be equivalent to a few megatons of TNT (or an earthquake of 7 Mag). The probe would take about a week to reach the core and would use 100,000 to 10 million metric tons of molten iron. Once on its journey, the probe would transmit data on temperature, electrical conductivity and chemical composition using high-frequency seismic waves.

Advertisement

Sources: 

http://www.icdp-online.org/front_content.php?idcat=695

http://superdeep.pechenga.ru/


Nature
  • geology,

  • drilling