Lonar lake

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The Lonar Lake ( Marathi : लोणार सरोवर , English Lonar Lake ) is a salt and soda lake near Lonar in the Buldhana district in the Indian state of Maharashtra . The lake was created by a meteorite impact during the Pleistocene . As site 22, it is one of the national geological monuments of India .

location

The crater lake with a temple in the foreground

The impact lake is located almost 1000 meters southwest of Lonar, around 140 kilometers east of Aurangabad .

history

The Lonar Lake was already mentioned in ancient religious writings such as the Skandapurana and the Padmapurana , and much later in the Ain-i-Akbari . The Ain-i-Akbari, written around 1600, describes the lake as follows:

“These mounds provide all the substances needed to make glass and soap. Saltpetre is also mined, which gives the treasury considerable tax revenues. In the hills there is a source of salt water, but the water from the center and the edges of the lake is completely enjoyable. "

The British officer JE Alexander was the first European to visit the lake in 1823. The Buldhana district in which the lake is located was once part of the Ashoka Empire and later the Shatavahana Empire . The Chalukya and Rashtrakuta also ruled the district once. Trade flourished during the rule of the Mughals , Yadava , Nizam and British. Several temples on the crater rim are Yadava temples or Hemadpanti temples (named after Hemadri Ramgaya ).

description

The almost circular impact crater is 480 meters above sea level and has an average diameter of 1200 meters, whereas the actual crater rim has a diameter of 1830 meters. The circumference of the lake is 4800 meters and its surface is 1.13 square kilometers. The height difference from the crater rim to the deepest point is 137 meters. The inside of the crater drops very steeply towards the lake at up to 75 °.

Geomorphologically , Lake Lonar can be divided into five zones:

  • the outer ejection cover
  • the crater rim
  • the inner crater slope
  • the crater basin
  • the crater lake in the crater basin.

Ambar Lake

Only 700 meters north of the actual crater lake is another small, water-filled depression, elongated to the northwest, the Ambar Lake or also Chota Lonar (Little Lonar). It is believed that this was the impact of a fragment chipped off by the meteorite. Nearby is a temple (Motha Maruti) dedicated to the god Hanuman (sleeping Maruti), the stone figure of which is said to be very magnetic and possibly comes from the meteorite. The neighboring farmers use the lake for irrigation purposes. Around 1000 meters to the south-east, a circular structure can still be seen, which has now almost dried out. However, nothing is known about their origin.

geology

Satellite image of Lonar Lake

The Lonar impact crater is the only known meteorite crater to date that has struck the basalt of the Deccan . Initially, a volcanic origin of the lake was assumed, but this is now attributed to the impact of a comet or asteroid . Confirmation of this theory can be found in plagioclases that have either been converted to maskelynite or contain PDFs. It is believed that only hypersonic impacts create these structures. Further evidence for the impact theory is provided by ray cones and deformed basalt layers at the crater rim, shocked breccias inside the crater and an ejecta cover of non-volcanogenic origin surrounding the crater .

The Lonar crater has a slightly oval shape, which indicates an impact coming from the east at an angle of 35 to 40 °.

Age

There are several estimates for the age of the crater. Early thermoluminescence examinations showed an age of 52,000 years, whereas newer argon-argon dates suggest a significantly older age up to 570,000 ± 47,000 years ( Middle Pleistocene ). This significantly higher age is in much better agreement with the erosion intensity at the crater.

ecology

The slopes on the crater lake are dominated by a tree savannah with the taxa teak Tectona grandis , Wrightia tinctoria , the Malabar lacquer tree Butea monosperma and the natural fiber Helicteres isora . Bush savannah thrives on the steep slopes with the acacia nilotica and the buckthorn plant Ziziphus sp. The taxon Prosopis juliflora , which immigrated from Central America, spreads on the lakeshore . The river delta of the Dhara in the northeast is used for agriculture, mainly millet , corn , bananas and papaya are grown .

The chemical conditions in the lake identify two regions that do not mix with each other and that are characterized by distinct flora and fauna:

  • a neutral outer zone with pH = 7
  • an alkaline inner zone with pH = 11.
The Hindu jack

The lake is a paradise for many plant and animal species. But local bird species are also many migratory birds to him protection, such as stilt walkers, ruddy shelduck , Grebe, Shelduck (European migratory birds), Anatinae, teals , herons, Red-wattled Lapwing , Indian Roller , Blue Jay, Baya Weaver , larks, tailor birds, magpies, robins and swallows. Among the reptiles, monitor lizards are particularly worth mentioning. At the lake there are also thousands of peacocks , Indian gazelles and other types of gazelle.

Microorganisms

Streptomyces alkalithermotolerans - an alkaliphilic and thermotolerant bacterial species from the genus Streptomyces - was isolated in the alkaline soda facies area of ​​Lake Lonar . Non-symbiotic nitrogen-fixing microorganisms such as Halomonas sp. , Paracoccus sp. , Klebsiella sp. , Slackia sp. and Actinopolyspora sp. were found in the lake in 2007. All nitrogen fixers are halo-alkaline because they only thrive at pH-11. Some of the bacteria and actinomycetes secreted from the lake water even thrive on inorganic substrates that contain components simulating the Martian soil.

Salinity

The lake water contains various salts (chlorides) or sodium salts (carbonates), which evaporate in dry periods when the lake level falls and can then be collected in large quantities. These salts are known by various local names. It has recently been in a core sample the carbonate Gaylussite discovered a hydrogenated Mischkarbonat of sodium and calcium of the formula Na 2 Ca (CO 3 ) 2 · 5H 2 O. It appears as translucent, glassy white, gray to yellowish prisms having monoclinic symmetry . The mineral is unstable, dehydrated in dry air and decomposed in water.

However, the lake has access to fresh water via the two brooks Purna and Penganga , and there is a freshwater well on the south side in the immediate vicinity of the lake.

temple

The Daitya Sudan in Lonar

As already mentioned at the beginning there are many temples at the lake or near the lake, several of which have already fallen into disrepair. An exception is Daitya Sudan in the center of Lonar, which was built in honor of Vishnu and commemorates his victory over the giant Lonasur. It is an exquisite example of early Hindu architecture. Other temples, all of which are in the crater area, are Vishnumandir, Ram Gaya, Wagh Mahadev, Mora Mahadev, Munglyacha Mandir and the temple of the goddess Kamalaja Devia at the edge of the lake. The Gomukh temple is on the rim of the crater and Shankar Ganesh is partly under water.

Individual evidence

  1. ↑ Geo-Heritage Sites, Minister oif Mines Press release, 09-March-2016
  2. ↑ Deshpande, Rashmi: The Meteor Mystery Behind Lonar Lake . In: National Geographic Traveler India . National Geographic Group, 2014.
  3. ↑ F. Jourdan, F. Moynier, C. Koeberl and S. Eroglu: 40Ar / 39Ar age of the Lonar crater and consequence for the geochronology of planetary impacts . In: Geology . tape 39 (7) , 2011, pp. 671-674 , doi : 10.1130 / g31888.1 .
  4. ↑ Riedel, Nils et al: Modern pollen vegetation relationships in a dry deciduous monsoon forest: A case study from Lonar Crater Lake, central India . In: Quaternary International . tape 371 , June 12, 2015, p. 268-279 , doi : 10.1016 / j.quaint.2015.01.046 .
  5. ↑ Sultanpuram, VR, Mothe, T and Mohammed, F .: Streptomyces alkalithermotolerans sp. nov., a novel alkaliphilic and thermotolerant actinomycete isolated from a soda lake . In: Antonie van Leeuwenhoek . tape 107 (2) , 2015, p. 337-44 , doi : 10.1007 / s10482-014-0332-z .
  6. ^ Avinash A. Raut and Shyam S. Bajekal: Nitrogen Fixing Bacteria from Hypervelocity meteorite impact Lonar Crater . In: Special Issue of Research Journal of Biotechnology . 2008.
  7. Jump up ↑ Avinash A. Raut and Shyam S. Bajekal: Nitrogen Fixing Actinomycetes from Saline Alkaline Environment of Lonar Lake: A Meteorite Impact Crater . In: Journal of Environmental Research and Development . Vol . 3, No. 3 , 2009.
  8. ↑ Avinash Anand Raut and Shyam S. Bajekal: Growth of Microaerophilic Nonsymbiotic nitrogen Fixing Microorganisms from Lonar Lake on Inorganic Medium containing Martian soil simulant components . In: Journal of Pure and Applied Microbiology . 2010.
  9. ↑ Ambili Anoop, Sushma Prasad, Birgit Plessen, Nathani Basavaiah, Birgit Gaye, Rudolf Naumann, Philip Menzel, Stephen Weise, Achim Brauer: Palaeoenvironmental implications of evaporative gaylussite crystals from Lonar Lake, central India . In: Journal of Quaternary Science . tape 5 , no. 4 , May 2013, p. 349–359 , doi : 10.1002 / jqs.2625 ( copernicus.org [PDF; 40 kB ; accessed on June 18, 2017]).

Coordinates: 19 ° 58 ′ 36 ″  N , 76 ° 30 ′ 30 ″  E