India and Asia collided millions of years ago to create rift in Siberian lakeFebruary 12th, 2009 - 12:57 pm ICT by ANI
Washington, Feb 12 (ANI): Scientists have determined that the geological collision between India and Asia millions of years ago created the area around Lake Baikal in Siberia.
That is the conclusion reached by two Danish researchers from the University of Copenhagen, Professor Hans Thybo and Dr. Christoffer Nielsen, after many seismic examinations, including blowing up tons of dynamite, and five years work of analyzing the data.
In the middle of Siberia lies the 2000km long Baikal Rift Zone, where, over the last 35 million years, a gigantic crack in the Earths crust has developed.
In the middle of this rift zone lies the worlds deepest lake, Lake Baikal, which is almost 1700m deep and contains 20 percent of the worlds freshwater.
Due to Lake Baikals isolated location, far from the worlds oceans, the microbial and animal life found here has undergone a unique evolution over the last 30 million years.
The Baikal Rift Zone, or fracture zone, is also special because it is located 3000km away from the nearest tectonic plate boundary.
Therefore, it has been difficult, until now, to explain the origin of the Baikal Rift Zone using commonly accepted geological premises and methods.
However, Prof. Hans Thybo and Dr. Christoffer Nielsen, in collaboration with Eastern European colleagues, have succeeded in uncovering what happened, and what is still happening, under the surface of one of the most special and distinctive areas on Earth.
More than that; the results from the experiment in Siberia have lead to a new understanding of, and model for, the formation of and activity in rift zones, which are found in locations around the globe, including between the continents.
In Siberia, the Danish research team lead a seismic experiment known as BEST (Baikal Explosion Seismic Transects) carried out around Lake Baikal.
The experiment included setting off of tons of dynamite so the scientists could follow the sound waves from the explosion as they travelled through the ground, using them to determine the structure of the Earths crust and the upper mantle and thus gain an understanding of the processes driving the rift zones development.
The results from Lake Baikal show that the 40-50km wide crack in the Earths crust is around 10km deep.
All previous models of rift processes have assumed that the bottom of the Earths crust would have a corresponding bulge.
However, to the researchers great surprise, it turned out that the bottom of the crust is flat across Lake Baikal.
The two scientists explain this phenomenon by a greater thinning of the crust than expected but at the same time also by an intrusion of magma into the bottom part of the crust layer. (ANI)
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