Lonar crater lake

Lonar Lake
Lonar crater full rim view with vegetation
Location	Buldana district, Maharashtra
Coordinates	19°58′36″N 76°30′30″E / 19.97667°N 76.50833°E / 19.97667; 76.50833 (Lonar Crater Lake)Coordinates: 19°58′36″N 76°30′30″E / 19.97667°N 76.50833°E / 19.97667; 76.50833 (Lonar Crater Lake)
Type	impact crater lake, salt lake
Basin countries	India
Surface area	1.13 km2
Average depth	150 meters

Lonar Lake is a saline soda lake located at Lonar in Buldana district, Maharashtra, India, which was created by a meteor impact during the Pleistocene Epoch.^[1] This lake, which lies in a basalt impact structure, is both saline and alkaline in nature. Geologists, ecologists, archaeologists, naturalists and astronomers have reported several studies on the various aspects of this crater lake ecosystem.^[2] Lonar Lake has a mean diameter of 1.2 kilometres (3,900 ft) and is about 137 metres (449 ft) below the crater rim. The meteor crater rim is about 1.8 kilometres (5,900 ft) in diameter. The circular depression bears a saline water lake in its central portion.^[3] The crater's age is usually estimated to be 52,000 ± 6,000 years (Pleistocene),^[4] although a study published in 2010 gives an age of 570,000 ± 47,000 years.^[5][6]

The Smithsonian Institution, the United States Geological Survey, Geological Society of India, and University of Sagar and the Physical Research Laboratory have conducted extensive studies about the site.^[7][8]

Biological nitrogen fixation was discovered in this lake in 2007.^[9]

Geographical features

A series of low hills surround the basin which has an oval shape (almost round) with circumference at top of about 8 km (five miles). The sides of the basin rises abruptly at an angle of about 75°. At the base, the lake has a circumference of about 4.8 km (three miles). The slopes are covered with jungle interspersed with teak trees. A belt of large trees about a mile broad runs all round the basin; this belt is formed of concentric rings of different species of trees. A ring of date-palms followed by a ring of tamarind trees (nearly 1.6 km or a mile broad) leads to a ring of babul trees, bounded on the inside by a belt of bare muddy space. This space is several hundred metres/yards broad, devoid of all vegetation (due to the soda content of the water) and covered with a whitish slimy soil. During the rainy season, the drainage into the lake covers this muddy space. The water of the lake contains various salts or sodas, and during dry weather when evaporation reduces the water level, large quantities of soda are collected. Two small streams drain into the lake, and a well of sweet water is located on the southern side, close to the water's edge.^[10]

The historical document called the Ain-i-Akbari (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.^[10]

Geological origin

Lonar Lake lies within the only known extraterrestrial impact crater found within the great Deccan Traps basaltic formation of India.^[11] The lake was initially believed to be of volcanic origin, but now it is recognized as an impact crater created by the hypervelocity impact of either a comet or an asteroid. The presence of plagioclase that has been either converted into maskelynite or contains planar deformation features (PDFs) has confirmed the impact origin of this crater. It is argued that only shock metamorphism caused by hypervelocity impact can transform plagioclase into maskelynite or create PDFs. The presence of shatter cones, impact deformation of basalt layers comprising its rim, shocked breccia inside the crater, and non-volcanic ejecta blanket surrounding the crater are further proof of the impact origin of Lonar crater.

Crater has oval shape. Meteorite impact came from the east, in a tilt of 35 - 40 degrees.^[12]

There are various estimates of the age of impact crater. Earlier thermoluminescence analyses gave a result of 52 thousand years, while recent Argon-argon dating testifies that this crater is much older - it could be 570 000 ± 47 000 years old. This greater age is in line with the degree of erosion processes of crater rims.^[5][12]

As a result of the studies, broadly, the geological features of the Lonar crater has been marked under five distinguishable zones, exhibiting distinct geomorphic characteristics.^[13]

The five zones are:^[14]

1. The outermost ejecta blanket
2. The crater rim
3. The slopes of the crater
4. The crater basin, excluding lake
5. The crater lake

Historicity

The lake was first mentioned in ancient scriptures such as the Skanda Purana, the Padma Puran and the Aaina-i-Akbari ^[15] The first European to visit the lake was British officer, J.E. Alexander in 1823.

Buldhana district in Maharashtra, where the lake is located, was once part of Ashoka's empire and then of Satavahana's. 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 (named after Hemadri Ramgaya).^[16]

Religious setting

Numerous temples surround the lake, most of which stand in ruins today, except for the temple of Daitya Sudan at the centre of the Lonar town, which was built in honour of Vishnu's victory over the giant Lonasur. It is a fine example of early Hindu architecture.^[17] Vishnumandir, Wagh Mahadev, Mora Mahadev, Munglyacha Mandir and Goddess Kamalaja Devia are the other temples found inside the crater.^[18]

Daitya Sudan temple

Daitya Sudan Temple is a Vishnu temple dated to the Chalukya Dynasty which ruled Central and Southern India between the 6th and 12th centuries. It belongs to the Hemadpanthi class and is built in the form of an irregular star. It features carvings similar to those seen at Khajuraho temples. The deity of this temple is made of an ore with a high metal content that resembles stone. The ceiling of the temple has carvings. The exterior walls are also covered with carved figures. The plinth of the temple is about 1.5 m in height and the unfinished roof suggests an intended pyramidal form for the tower.

The temple of Daitya Sudan at Lonar is the best example of the Hemadpanthi style. From the standing image of Surya in the principal niche on the back of the temple it is conjectured that the temple was originally dedicated to the Sun god. However, in the present form its vaishnav temple of god vishnu in its daityasudan avatar. There is a story that a demon by the name of Lonasur or Lavanasur used to reside in this locality along with his sisters. He was killed by lord Vishnu in his Daityasudan Avatar hence the name.

The temple measures 105 ft. long by 84.5 ft. broad. It is a tree chamber temple, the inner most being garbh grub, the sanctum sanctorum, where the idol of lord vishnu standing atop lavanasur is there. The present day idol was made by bholse rulers of Nagpur after the original went missing. The second chamber is called antarl where individual pooja are performed, on the roof of this block one can see beautiful cravings of puranic stories viz. Killing of Lavanasur by Lord Krishna and appearance of Dhar of Lonar; story of Kansa and Krishna, story of Narasimha and HiranKashyap and lastly raskrida. The outermost chamber is called as sabhamandap which is meant for group offerings and performance. This portion as well as the entrance gate does not match the style and construction elements of the temple overall. The brickwork might have been added later to the damaged or unfinished temple, which may be attributed to various invasions post the 10th century.

The main entrance of the temple is east facing. The principle niche at the back of the temple has an image of Surya, the sun god, which gives rise to the speculation that this might have been dedicated to him. The niche on south has an image of Chamunda. The one on left of the temple i.e. north has narashima in it. All of these 3 niches are built like mini temples in themselves having elaborate pillars, base and decoration.

There are nemorous ridges onto the temple with different decoration, images having iconic as well as artistic significance. Many of the images depict deities or incidents on Hindu purans. ^[19]

Kamalja Devi Temple

Kamalja Devi Temple is located beside the lake and also features carved images. Although the water level rises during the rainy season and falls in summer, the temple is located above the water level.

Gomukh Temple is located along the rim of the crater. A perennial stream emerges from here and pilgrims visiting the temple bathe in the stream.^[20]

By-products of the lake

The Gazetteer chronicles the findings of the British administrators and scientists, notably, Colonel Mackenzie, Scientist Dr. I. B. Lyon, Mr. J. O. Malcolmson and Mr. Plymen, Agricultural Chemist. Some extracts from Mr Plymen's report, given in quotes, are informative.<ref name="Maha" "> - Working of the Lake</ref>

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 Rajsthan(India), 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.^[21]

Dalla Nimak 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.^[21]

Commercial exploitation of the salts from the lake is recorded from 1842, including the period of Government of His Highness Nizam, and until 1903. Presently, there is only a very small local demand for these Lonar Lake products.^[21]

Lake ecosystem

The chemical characteristics of the lake shows two distinct regions that don't mix - an outer neutral (pH 7) and an inner alkaline (pH 11) each with its own flora and fauna. The lake is a haven for a wide range of plant and animal life. Resident and migratory birds such as black-winged stilts, brahminy ducks, grebes, shelducks (European migrants), shovellers, teals, herons, red-wattled lapwings, rollers or blue jays, baya weavers, parakeet 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.^[22]

Nitrogen fixing microorganisms

Nonsymbiotic nitrogen fixing micro-organisms such as Halomonas sp., Paracoccus sp. Klebsiella sp., Slackia sp. Actinopolyspora sp. have been reported from this lake. All the nitrogen fixers are haloalkaliphilic in nature as they can grow only at pH-11. Some of the bacteria and actinomycetes isolated from this lake are able to grow on some components of inorganic medium containing martian soil simulant components.^[23]

Threats to Lonar lake

Lonar lake faces anthropological and environmental problems as listed below:

• Use of fertilizers, pesticides and toxic materials in the agriculture field around the lake results in pollution of lake water.

• One of the water sources for the lake is small river stream Dhara, Sita Nhani. The household effluents containing detergents are regularly disposed off here.

• Deforestation is illegally carried out in the surrounding and cattle grazing inside or near the rim of crater creates fecal pollution.

• Excavation activities are often carried out illegally thus disturbing the lake's underground water source.

• The government is unable to raise funds needed for preserving this crater and often tourist activities continue to cause environmental damage to nearby land.

• During local festival such as Kamala Devi festival, large number of pilgrims enter the crater. Small shops, food-stalls are often established near the crater or along its rim.

• Among the frequent visitors are the religious visitors from nearby towns and villages who are not adequately educated by the means of signboards and attending officials about littering and maintaining the beauty of this nationally important destination.

Crater is protected as a geological landmark and authorities have recognized the role of the historical and archaeological heritage in the lake, nevertheless action is needed to prevent the adverse impact of settlements and religious festivities on local ecosystem. Various civic activities (e.g. "Save Lonar") in protection of Lonar crater are on-going.

See also

• Soda lake
• List of lakes in India
• Lonar (town)

References

External links

Wikimedia Commons has media related to Lonar crater lake.

• 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.

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