Lonar Lake

Lonar Lake, also known as Lonar crater, is a saline, soda lake, located near Lonar, 79 km from Buldhana city in Buldhana district, Maharashtra state, India. It has been designated as a National Geological Monument, and is the only crater lake of meteoritic origin in the country. It has a mean diameter of 1.2 kilometres (3,900 ft), and sits about 137 metres (449 ft) below the crater rim, which is about 1.8 kilometres (5,900 ft) in diameter. Located inside the Deccan Plateau —a massive plain of volcanic basaltic rock created by eruptions some 65 million years ago— it was first supposed to be of volcanic origin. However, further studies concluded that the lake formed inside an impact crater of meteoritic origin from the Pleistocene. Previously believed to be 52,000 ± 6,000 years old, newer studies suggest an age of 576,000 ± 47,000 years. It is one of only four known hypervelocity (of 11 km/s or greater) impact craters in basaltic rock anywhere on Earth; the other three impact structures are in southern Brazil. The Smithsonian Institution, the United States Geological Survey, the 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. Geography The lake is situated in an endorheic basin, with a near-circual shape (which seems to indicate an eastwards impact at a 35–40 angle), and a circumference of about 8 kilometres (5.0 mi), enclosed by steep sides that rise sharply at an angle of about 75°. The lake's circumference at the sides' base is about 4.8 kilometres (3.0 mi). Its location on the Deccan Plateau initially made scientists believe that the crater was volcanic, however, the presence of plagioclase that has been either converted into maskelynite or contains planar deformation features has confirmed the extraterrestrial impact origin. It is believed that only shock metamorphism caused by a hypervelocity impact can produce such geological features. Furthermore, 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. Earlier thermoluminescence analyses of the structure's age 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. The lake lacks an outflow, which leads to a concentration of minerals as the water evaporates, making it high in salinity and alkalinity. The levels, however, are not homogenous: the lake presents an outer neutral (of pH 7) region, and an inner alkaline (of pH 11) region that do not intermix, generating two distinct chemical environments. Floral, faunal, and microbial diversity Teak can be found growing along the slopes of the crater, as well as dyer's oleanders, flames of the forest, Indian screw trees, thorn mimosas, and plants of the Ziziphus genus. Non-native Neltuma juliflora seems to be spreading along the lake's shore as well. Alongside wild flora, millet, maize, okra, banana, and papaya are among the most widely cultivated crops around Lonar Lake. Resident and migratory birds such as black-winged stilts, brahminy ducks, grebes, shelducks, shovelers, teals, herons, red-wattled lapwings, blue jays, baya weavers, parakeets, hoopoes, larks, tailorbirds, magpies, robins, Asian woolly-necked storks, common pochards and swallows are also found on the lake. The area is also home to land-dwellers, such as the monitor lizard, peafowls, chinkaras, grey wolfs, and gazelles. Dense blooms of cyanobacteria, such as of the genus Arthrospira, give the lake its characteristic green colour. Despite this, a great number of other bacteria, and archaea, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers, heterotrophs, and syntrophs have been reported. Diverse alveolates, fungi, stramenopiles, choanoflagellates, amoebozoans, cercozoans, and many novel lineages of putative micro-eukaryotes were detected in molecular surveys of Lonar Lake sediments. A new species of fungus Curvularia lonarensis has been described from the lake. 2020 colour change In early June 2020, the lake changed its characteristic green colouring to a shade of red in a span of 2–3 days. Reports by the Agharkar Research Institute, National Environmental Engineering Research Institute, and Geological Survey of India suggested that lowered water levels and high salinity caused increased growth of Halobacterium and increased Carotenoid levels, which in turn led to colour change. History First mentions of the Lonar Lake date back to ancient Sanskrit scriptures, such as the Skanda Purana and the Padma Purana. A 16th-century Mughal document, the Ain-i-Akbari, seems to mention the lake as well: 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.The region where the crater is located has changed hands a number of times throughout history. The Maurya, Satavahana, and Rashtrakuta Empires, as well as the Chalukya dynasty, and later the Mughals, Yadavas, the Nizam of Hyderabad, and, finally, the British conquered, and administered this part of the Indian subcontinent.Religious temples dot the periphery of the lake, and while many now lie in ruins, the Daitya Sudan Temple has managed to survive to this day. It is dedicated to Vishnu —one of the principal deities of Hinduism— that, according to a legend, slayed a giant named "Lonasura" (alternatively, "Lavanasura") that terrorized humans, and animals. During the confrontation, it is said that he uncovered the giant's underground dwelling, threw open the lid, and slew him. The legend may be directly tied to the lake, and constitute a mythical explanation of its origins. Other temples that can be found in the area include: The Kamalaja Devi Temple, which is located beside the lake, and also features carved images. The Gomukha Temple, located along the rim of the crater. A perennial stream has its source near the temple, which the pilgrims visit. The Shankara Ganesha Temple, which is partially submerged, and is noted for the presence of a rectangular Shiva statue. The Rama Gaya Temple. The Motha Maruti Temple, which is located near the secondary Ambar Lake, 700 m (2,300 ft) from the main lake, believed to be caused by a fragment of the main meteor. The Government of Maharashtra has declared the lake, and the adjoining area as Lonar Wildlife Sanctuary on 8 September 2000. The adjoining area was declared as "Eco-sensitive Zone" on 21 February 2017. In 2022, the government of Maharashtra began plans to develop the site as a tourist attraction. Still, the integrity of Lonar Lake is being threatened by the use of fertilisers, pesticides, and toxic materials in agricultural fields —which results in water pollution— illegal deforestation, illicit mining, irregular commercial construction in the lake's vicinity, disrupting the natural topography, detergents regularly reaching the lake due to the use of two perennial streams by the locals, littering, sewage dumping, among many others. Gallery See also Impact craters in India Dhala crater in Shivpuri district of Madhya Pradesh Luna crater at Kutch district of Gujarat Ramgarh Crater in Mangrol tehsil of Baran district of Rajasthan Shiva crater, a disputed undersea super crater west of India Other related topics List of impact craters on Earth List of possible impact structures on Earth List of lakes in India List of national parks of India Ramsar Convention Soda lake Tiger reserves of Maharashtra External links Lonar crater, India: an analog for martian impact craters, Lunar and Planetary Science XXXVIII abstracts. Lonar, A Gem of Craters SPARK Volume 2, K-12 outreach, Space Science and Engineering Centre, University of Wisc-Madison. Lonar Lake changes color from green to pink, NASA Earth Observatory, June 19, 2020 Trekking to Lonar Lake References External links Lonar crater, India: an analog for martian impact craters, Lunar and Planetary Science XXXVIII abstracts. Lonar, A Gem of Craters SPARK Volume 2, K-12 outreach, Space Science and Engineering Centre, University of Wisc-Madison. Lonar Lake changes color from green to pink, NASA Earth Observatory, June 19, 2020 Trekking to Lonar Lake