Lonar Lake

Lonar Lake, also known as Lonar crater, is a saline, soda lake, located at Lonar, 79 km from Buldhana city in Buldhana district, Maharashtra, India.
It is a notified National Geo-heritage Monument.
Lonar Lake is in an impact crater created by a meteorite impact during the Pleistocene Epoch. It is one of only four known hyper-velocity impact craters in basaltic rock anywhere on Earth. The other three basaltic impact structures are in southern Brazil. Lonar Lake has a mean diameter of and is about below the crater rim. The meteor crater rim is about in diameter.
Although the crater's age was previously estimated to be 52,000 ± 6,000 years, newer studies suggest an age of 576,000 ± 47,000 years.
Lonar Crater sits inside the Deccan Plateaua 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. The water in the lake is both saline and alkaline.
Geologists, ecologists, archaeologists, naturalists and astronomers have published studies on various aspects of the ecosystem of this crater lake.
The Smithsonian Institution, the United States Geological Survey, Geological Survey of India, the University of Sagar and the Physical Research Laboratory have conducted extensive studies of the site. Biological nitrogen fixation was discovered in this lake in 2007.
A 2019 study, conducted by IIT Bombay found that the minerals in the lake soil are very similar to the minerals found in Moon rocks brought back during the Apollo Program. The lake was declared a protected Ramsar site in November 2020.

Geographical features

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 sides of the basin rise abruptly at an angle of about 75°. At the base of the sides, the lake has a circumference of about 4.8 km. The slopes are covered with tree-savannah, housing teak, Wrightia tinctoria, Butea monosperma, and Helicteres isora, and with shrub-savannah housing Acacia nilotica and Ziziphus spp.. Along the lake shore, non-native Prosopis juliflora is spreading. Millet, maize, okra, banana, and papaya are the main cultivated crops.
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.

Geological origin

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 ejecta blanket surrounding the crater all support the impact origin of Lonar Lake.
The crater has an oval shape. The meteorite impact came from the east, at an angle of 35 to 40 degrees.
There are various estimates of the age of the crater. Earlier thermoluminescence analyses gave a result of 52,000 years, while recent argon-argon dating suggests that the crater is much older; it could be 570 000 ± 47 000 years old. This greater age is in line with the degree of erosion of the crater rim.
As a result of the studies, the geological features of the Lonar crater have been divided into five distinguishable zones, exhibiting distinct geomorphic characteristics.
The five zones are:

The outermost ejecta blanket
The crater rim
The slopes of the crater
The crater basin, excluding lake
The crater lake
History

The lake was first mentioned in ancient scriptures such as the Skanda Purana and the Padma Purana.
The Ain-i-Akbari, a document written about 1600 CE, states:

These mountains produce all the requisites for making glass and soap. And here are saltpetre works which yield a considerable revenue to the State, from the duties collected. On these mountains is a spring of salt water, but the water from the centre and the edges is perfectly fresh.

Buldhana district in Maharashtra, where the lake is located, was once part of the Maurya Empire and then part of the Satavahana Empire. The Chalukyas and Rashtrakutas also ruled this area. During the period of the Mughals, Yadavas, Nizam, and the British, trade prospered in this area. Several temples found on the periphery of the Lake are known as Yadava temples and also as Hemadpanti temples.
In 2022, the government of Maharashtra began plans to develop the site as a tourist attraction.

Ambar Lake

There is a small circular depression at a distance of around from the main lake, believed to be caused by a fragment of the main meteor. There is a Hanuman temple near this lake, with the idol made of rock believed to be highly magnetic. The water from Ambar lake is being drained by local farmers. This lake is sometimes also called Chhota Lonar.

By-products of the lake

The Gazetteer chronicles the findings of the British administrators and scientists, notably, Colonel Mackenzie, scientist Dr. I. B. Lyon, J. O. Malcolmson and Plymen, agricultural chemist. Some extracts from Plymen's report, given in quotes, are informative.

The saline deposits obtained from the lake are rather of an exceptional nature. Compared with the most famous salt lake in India, the Sambhar Lake in Rajasthan, it will be seen that whereas at Lonar the carbonates of soda are the most important, in the case of the Sambhar Lake the deposits of sodium chloride or common salt give the lake its value. The modes of formation are also entirely different and it is practically certain that the Lonar salts are derived from an unknown source in the bed of the lake. It is true that water is continually flowing into the lake and that except by evaporation there is no loss. The main feeder stream could not however supply this amount of alkali nor could the other smaller supplies coming in during the rains, for on all sides of the lake vegetation is abundant, particularly where the main stream flows in continuously. Were any quantity of alkali present in this water, vegetation would suffer considerably and, with exception of a few varieties of plants, eventually die out entirely.

The salts collected from this lake vary in their nature and composition and from their-appearance are easily separated by men accustomed to handling them. Various names are given to some five or six main varieties, but there is no fixed line between one salt and another, their compositions depending upon the period and condition of crystallization. At the present time large quantities of these salts are lying on the shores of the lake...

With the process of crystallization, sodium chloride or common salt is formed along with the carbonates of soda resulting in a number of products, as explained below.
Kala Namak and Nimak Dalla are found in white crystalline masses. Khuppal is obtained in solid compact lumps and consists of a mixture of carbonates and chlorides in roughly equal proportions. Pipadi or Papri, which has a similar chemical composition, is very different in appearance. It is frequently tinged, slightly pink in colour and hollow air spaces are found between the crystalline masses which are formed in flakes or layers. Bhuski has no definite structure but consists of a soft flaky powder mixed with a quantity of impurity. It can be compared to small salt substance or baking soda.
The salts are not all obtained in the same way or at the same period of the year. Pipadi and bhuski are deposited on the shores of the lake as the water dries up in the hot weather, pipadi being the upper layer and therefore the purer. Except for bhuski, the salts are in a fairly pure state and contain only small proportions of earthy matter. Their further purification is not considered difficult.
Commercial exploitation of the salts from the lake is recorded from 1842, including the period of Government of Nizam, and until 1903. Presently, there is only a very small local demand for these Lonar Lake products.

Gaylussite mineral

is the mineral has been recently reported from drill core in Lonar lake. Gaylussite is a carbonate mineral, a hydrated sodium calcium carbonate, formula Na₂Ca₂·5H₂O. It occurs as translucent, vitreous white to grey to yellow monoclinic prismatic crystals. It is an unstable mineral which dehydrates in dry air and decomposes in water.
Streptomyces alkalithermotolerans is an alkaliphilic and thermotolerant bacterium species from the genus of Streptomyces which has been isolated from the Lonar soda lake in India.

Lake ecosystem

The chemical characteristics of the lake shows two distinct regions that do not mix – an outer neutral and an inner alkaline each with its own flora and fauna. The lake is a haven for a wide range of plant and animal life.
The site has 160 bird, 46 reptile and 12 mammal species. Resident and migratory birds such as black-winged stilts, brahminy ducks, grebes, shelducks, shovelers, teals, herons, red-wattled lapwings, rollers or blue jays, baya weavers, parakeets, hoopoes, larks, tailorbirds, magpies, robins and swallows are found on the lake.
Among reptiles, the monitor lizard is reported to be prominent. The lake is also home to thousands of peafowls, chinkara and gazelles. The area of was declared as Lonar Wildlife Sanctuary by the government on 20 November 2015.