Mysterious Ice Circle of Lake Baikal

On 2009, a mysterious phenomenon on the lake occurred, when strange, huge circles with diameters of up to 4.4 km started to appear in the ice of Russia’s Lake Baikal during particularly cold months. The bizarre circular ice formations were first spotted by astronauts aboard the International Space Station (ISS) and their discovery immediately ignited speculation as to their cause. They charted the progress of the circles when they first appeared on April 5 until April 27 when the ice was beginning to split apart.

Lake Baikal is in a rift valley and is the largest (by volume) and deepest (5,400ft) fresh water lake on Earth. The World Heritage site is also one of the world’s oldest lakes aged between 25 to 30million years old. Sediment deposited on the bottom is up to 4.3 miles deep. This lake is the only confined freshwater lake in which direct and indirect evidence of gas hydrates exists. 

Circle of thin ice with diameter of 4.4 km

 

The two circles are the focal points for ice break-up and may be caused by upwelling of warmer water in the lake. The dark color of the circles is due to thinning of the ice, which usually hangs around into June. Circles have been seen in that area before in 1985 and 1994, though they weren’t nearly as pronounced. 

It is currently believed that the ice circles are the result of methane gasses gurgling up from the bottom and resulting in swirling warm water currents that then formed the circular formations on the lake ice.

Ice cover changes rapidly at this time of year on the Russian lake and can melt and freeze overnight. Scientists believe a spurt of warm water rose to the surface creating the distinctive pattern but are puzzled by the source of heat. Hydrothermal activity and high heat flow has been observed in other parts of the lake but one of the circles appeared near the southern tip, over relatively deep - normally cold - water.

Sources:
http://en.wikipedia.org/wiki/Lake_Baikal

http://www.dailymail.co.uk/sciencetech/article-1188879/Mysterious-ice-circles-remote-Siberian-lake-baffle-scientists.html

http://mysteriousuniverse.org/2014/12/the-deep-mysteries-of-the-worlds-deepest-lake/

http://www.wired.com/2009/05/astronauts-spot-mysterious-ice-circles-in-worlds-deepest-lake/

Pic Source:
http://en.wikipedia.org/wiki/File:Circles_in_Thin_Ice,_Lake_Baikal,_Russia.jpg