|The Kola Superdeep Borehole|
For 24 years, Soviet scientists dug deeper into the Earth’s surface than anyone had ever done before. The result was the Kola Superdeep Borehole located on the Kola Peninsula in Russia.
The ambitious project began in the 1970s, and scientists in the former Soviet Union began to drill a hole that was just 9-inches in diameter. The hole eventually extended 7.5 miles into the Earth’s crust, farther than the deepest point in the ocean, Challenger Deep in the Marianas Trench in the Pacific Ocean at 6.8 miles.
What did the scientists learn, and what did they find at these incredible depths? Quite a lot actually. They found single-celled plankton organisms at 4.3 miles down, and at nearly the same depth they discovered water. They also discovered that the temperature reached 356° F at the bottom of the hole which was more than their estimates. This became the reason the hole had to be eventually abandoned in 1994. The hole was simply too hot for drilling to continue. The environment became more liquid because of the hot conditions, and the borehole was increasingly more difficult to maintain. Plus it ruined equipment quickly. But the scientists were able to more accurately estimate the distance to the center of the Earth to almost 4,000 miles. Their hole was only a drop in the bucket compared to the massive distance farther to the Earth’s center. The hole barely made it into the Earth’s crust, which is about 23 miles thick. The goal had been to extend into the Earth’s mantle, which is approximately 1,800 miles thick under the crust.
|The borehole welded shut Rakot13/Wikimedia|
The first attempt at getting to the mantle took place in 1958 off the coast of Guadalupe, Mexico in the Pacific Ocean called Project Mohole. American engineers drilled in 11,700 feet of water and extended a hole 601 feet beneath the seafloor. They project ran out of funding in 1966. The next large attempt happened from 1987 to 1995 where the German Continental Deep Drilling Program was begun by German scientists in Bavaria. They managed to get about 5.7 miles down and discovered temperatures that got as high as 600° F. They too ran out funding.
Since the Earth’s crust is thinner under the ocean floor, that is where the next attempt at going deeper is set to take place. The Chikyu, a specialized Japanese drill ship, has the record for the deepest offshore hole used for scientific purposes at almost 2 miles beneath the sea floor. An international team that is using the Chikyu is now attempting to go deeper. The Integrated Ocean Drilling Program was begun in 2003 and is trying to get to the Earth’s mantle, where temperatures can start at 1,600° F. The program will take many years, and it’s cost may reach $1 billion.
Top Photo Credit: Belozeroff/Wikimedia