Lonar Crater sits inside the Deccan Plateau—a massive plain of volcanic basalt rock created by eruptions some 65 million years ago. Its location in this basalt field suggested to some geologists that it was a volcanic crater. Today, however, Lonar Crater is understood to be the result of a meteorite impact that occurred between 35,000 and 50,000 years ago.The water in the lake is both saline and alkaline.
A series of small hills surround the basin, which has an oval shape, almost round, with a circumference at top of about 8 km .
The water of the lake contains various salts and sodas. During dry weather, when evaporation reduces the water level, large quantities of soda are collected. Two small streams, named Purna and Penganga, drain into the lake, and a well of fresh water is located on the southern side, close to the water's edge.Lonar Lake lies within the only known extraterrestrial impact crater found within the great Deccan Traps, a huge basaltic formation in India. The lake was initially believed to be of volcanic origin, but now it is recognized as an impact crater. Lonar Lake was created by the impact of either a Comet or of an Asteroid. The presence of plagioclase that has been either converted into Maskelynite or contains Planar deformation features has confirmed the impact origin of this crater. It is believed that only shock metamorphism caused by a hypervelocity impact can transform plagioclase into maskelynite, or create planar deformation features. The presence of impact deformation of basalt layers comprising the rim, of shocked Breccia inside the crater, of shatter cones, and of the non-volcanic Ejection blanket surrounding the crater all support the impact origin of Lonar Lake.
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