2023-06-11 06:03:26
For the first time in history, geologists have managed to drill through the entire earth’s crust and extract samples of the mantle, the largest layer of the Earth’s interior, from the depths of our planet. Scientists have been moving towards this for a very long time and in different parts of the world. For example, in the 1960s, the Mohol project was launched in the United States, in which researchers managed to drill five wells 180 meters deep under water. And in 1970, the drilling of the Kola super-deep well began, the depth of which eventually exceeded 12,000 meters. These were impressive achievements, but no group of geologists has yet been able to get so close to the earth’s mantle. It was possible to achieve it thanks to new technologies and ingenuity of scientists.
Scientists managed to get samples of the earth’s mantle – for this they had to go to the trick
What layers does the earth consist of?
Since school days, we have known that the planet Earth consists of three layers: the upper crust, the middle mantle and the deep core. In fact, the structure of our planet is very similar to the structure of a chicken egg: the bark is like a shell, the mantle is like a protein, and the core is like a yolk.
An image that clearly shows the internal structure of the Earth
The earth’s crust is the thinnest layer of the globe, but people still have not been able to fully drill through it and reach the mantle. The thickness of the earth’s crust is different everywhere – in mountainous areas the thickness can reach 100 kilometers, and under the seas and oceans this figure is 6-7 kilometers.
The thickness of the earth’s crust is different everywhere – in the depths of the oceans it is the least
It is not difficult to understand that in order to take samples of the Earth’s mantle, it is better for geologists to drill a well under water, because there the layer of the earth’s crust is thinnest. However, this is a very difficult task, because it requires a reliable vessel, a powerful drilling rig, high temperature and pressure resistant equipment and technology to help keep the rig as level as possible during drilling.
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The deepest holes in the earth
Since the second half of the 20th century, people have tried several times to drill the deepest possible hole in the ground. It is believed that following extracting samples of the mantle, it will be possible to learn a lot of interesting things regarding the internal structure of the Earth and the processes that take place there.
Mohol Earth Drilling Project
From 1961 to 1966, American scientists tried to drill through the earth’s crust as part of the Mohol project. In particular, the experts planned to reach the Mohorovichic boundary, the lower boundary of the earth’s crust, which separates the crust from the mantle.
Drilling platform CUSS I
For drilling, the CUSS I platform was used, which sailed to the volcanic island of Guadalupe, which is located in a section of the Pacific Ocean with a depth of regarding 3.5 kilometers. During the long work, scientists were able to make five wells with a maximum depth of 180 meters, but the goal was not achieved – the project was closed due to funding problems.
Participants of the Mohol project
Kola Superdeep Well
From 1970 to 1991, in the Russian Kola Peninsula, a well was drilled to a depth of 12,262 meters. Up to a depth of 7,000 meters, specialists used the Uralmash-4E installation, and following it, the Uralmash-15000. The well was completely closed in 1994 following a series of accidents. In 1997, the Kola superdeep well entered the Guinness Book of Records as an example of the deepest human invasion of the earth’s crust.
Open Kola Superdeep Well
In 2008, the Kola Superdeep field lost its record holder status because the Maersk Oil BD-04A well, 12,290 meters deep, appeared in the Al Shahin oil basin (Qatar). And in 2017, a well 15 meters deep appeared on the shelf of Sakhalin Z-44 Chayvo (Russia).
На сегодняшний день известно, что мантия оказывает большое влияние на лежащую сверху земную кору — она участвует в движении континентов, извержениях вулканов, землетрясениях и так далее. В ходе исследований ученые часто узнают о мантии много нового. Например, в 2023 году в ней был обнаружен новый слой, о котором ранее никто не знал.
Scientists have obtained samples of the Earth’s mantle
As part of the Mohol project and during the drilling of the Kola super-deep well, people might not reach the mantle – either there was not enough funding, then there was not enough equipment, or the thickness of the earth’s crust was too large. But today these problems have already been solved. Engineers have long built reliable ships, drilling tools can withstand even the most extreme conditions, and the GPS navigation system allows you to keep the drilling rig as level as possible without any problems.
In April 2023, geologists, microbiologists and other scientists boarded the research vessel JOIDES Resolution and set off to drill the newest, deepest underwater well. They found a good place for drilling – the choice fell on the Atlantis massif, which is a group of seamounts in the northern part of the Atlantic Ocean. In 1981, scientists discovered that at the junction of the American and African continents there is a particularly thin layer of the earth’s crust, the thickness of which does not exceed 1000 meters.
The drilling was carried out in a hydrothermal field called “The Lost City” at the bottom of the ocean.
Within a few months, the crew of the JOIDES Resolution ship was able to drill a well to a depth of 1,267 meters. Compared to the projects mentioned above, this is very small, but thanks to the choice of a place with a minimum thickness of the earth’s crust, scientists were able to extract samples of the mantle. During the work, the temperature at great depths reached 204 degrees Celsius.
Ship JOIDES Resolution
It is important to note that, technically, scientists did not reach the Earth’s mantle, but extracted its samples from the “tectonic window” – the area in which mantle rocks were pushed closer to the Earth’s crust. According to expedition member Leslie Anderson, the mantle rocks are extremely difficult to access, but the Atlantis massif made it possible for them to get to them.
Earth mantle samples mined in 2023
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In the near future, scientists will study the obtained samples. A cursory analysis has already shown that they contain peridotite, a rock that is common in the upper mantle. It is possible that the composition of the rocks was changed as a result of contact with sea water, so scientists want to continue drilling and extract even deeper samples.
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