The Kola borehole penetrated about a third of the way through the Baltic Shield continental crust, estimated to be around 35 kilometres (22 mi) deep, reaching Archaean rocks at the bottom. The project has been a site of extensive geophysical studies. The stated areas of study were the deep structure of the Baltic Shield, seismic discontinuities and the thermal regime in the Earth's crust, the physical and chemical composition of the deep crust and the transition from upper to lower crust, lithospheric geophysics, and to create and develop technologies for deep geophysical study.
The Kola Superdeep Borehole is the result of a scientific drilling project of the Soviet Union in the Pechengsky District, on the Kola Peninsula. The project attempted to drill as deep as possible into the Earth's crust. Drilling began on 24 May 1970 using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. Boreholes were drilled by branching from a central hole. The deepest, SG-3, reached 12,262 metres (40,230 ft; 7.619 mi) (Needs verification. According to markings written on the borehole, the depth is 12,226 m, ) in 1989 and is the deepest artificial point on Earth, as of August 2019. The borehole is 23 centimetres (9 in) in diameter.
In terms of true vertical depth, it is the deepest borehole in the world. For two decades it was also the world's longest borehole in terms of measured depth along the well bore, until it was surpassed in 2008 by the 12,289-metre-long (40,318 ft) Al Shaheen oil well in Qatar, and in 2011 by the 12,345-metre-long (40,502 ft) Sakhalin-I Odoptu OP-11 Well (offshore from the Russian island of Sakhalin)
To scientists, one of the more fascinating findings to emerge from this well is that no transition from granite to basalt was found at the depth of about 7 km (4.3 mi), where the velocity of seismic waves has a discontinuity. Instead the change in the seismic wave velocity is caused by a metamorphic transition in the granite rock. In addition, the rock at that depth had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock.
Microscopic plankton fossils were found 6 kilometers (4 mi) below the surface.
Another unexpected discovery was a large quantity of hydrogen gas. The mud that flowed out of the hole was described as "boiling" with hydrogen
Music Credit :
Martian Cowboy Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
creativecommons.... incompetech.com/ audionautix.com/ audionautix.com/
Негізгі бет संसारको गहिरो खाडलमा रेकर्ड गरिएको || Kola Super deep borehole || Bishwo Ghatana
Пікірлер: 1,6 М.