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GEOLOGICAL STUDY TOUR

AT

LONAR LAKEAN EXCURSION REPORT

INTRODUCTION

Lonar lake, near Lonar village in the Buldhana District, is not just

he source of Excitement for the visitors but also for the scientist

community. Lonar is the third natural salt-water lake in the world, with

a diameter of 1800 meter. It comes after Bosmatvi lake in Ghana,

which has a diameter of 10000 meter and New Cubec lake in Canada

with a Dai of 3500 meter.

The lake is circular except on the north-east side, where siltation

caused by the Dhara has created small mudflats. The diameter of the

lake is about 1600m. The crater is 150 meters in depth and is

absolutely confined from all sides by the walls of the crater and thereis not a single channel of water draining away from it, thereby leaving

the lake waters stagnant for thousands of years, a large portion of the

lake is rather shallow, preserving about 2meters of water during the

monsoon months. This may get reduced to only a few inches during

the summer. However, the lake is dried up completely in the year

1991.

HISTORIC BACKGROUND

The official dug up the heart of the lake and conducted experiments on

the material gathered from there, before making their announcement

public. The scientists also found some mineral found mostly in meteor-

hit areas. Traces of Sodium Carbonate and magnetic properties were

also observed in the soil there. Apart form its scientific importance;

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Lonar also occupies a place of prominence in our ancient scripts. It

finds mention in "Aaina-E-Akbari" During the days of Emperor Akbar, a

salt factory was located here.

According to Sanskrit Literature, Lonar was called "Viraj Kshetra"

in ancient times. It finds mention in "Viraj Mahatmya" a chapter in

"Skanda Puran and Padma Puran" Sanskrit works. According to Lonar

Mahatmya in ancient times, Kashyap Rishi had many sons. One of

whom was believed to be staying in the vicinity of Lonar Lake. When

Lavanasur terrorized the people and rulers of the region, the son of

Rishi Kashyap had prayed to Lord Vishnu to kill Lavanasur. In the 13 th

Century, a temple of Lord Vishnu as constructed there during the

Chalukya Raj. The temple still exists and is 150mt long and 450 mt.

wide. IT is a fine example of the quality of architecture practiced and

perfected during that era. Near the Lonar Lake is the Paphareshwar

pilgrimage. The engravings on the temple located there are in Sanskrit

and sadly they have still not been deciphered.

To add to its natural beauty the Lake has enough fauna in its

surroundings making it a serene and scenic spot.

ORIGIN OF LONAR LAKE

The Lonar crater has attracted the attention of world geologists

for investigation of its origin and the source of salinity of lake water.

Malcamson (1840), Bradley (1853), Smith (1857), Brandford (1870),

Medlicott and Brandford (1879), Oldham (1909), Nandi and Dev (1961),

Venkatesh (1983), Mishra (1987) and Badve and Kumaran (1992) have

suggested the views about the origin of the Lonar, according to them

the crater was believed to formed by some phase of volcanic activity.But the work of Beals et al (1960), Arogyaswamy (1962), the evidence

of glassy objects near the Lonar crater (Nayak 1972), impact affected

minerals by Fredrickson et al (1973), Fudalay and Fredrickson (1992)

and Haggerty and Newsom (2003) suggested that the Lonar crater was

formed by the impact of a meteorite.

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According to scientists, about 50,000 year back a massive

meteor entered into the Earth's gravitational forces range. 60 meter

long and weighing 20 lac ton it was racing at a speed of 25 km per

second towards the planet. When it struck the earth the energy

released was equivalent to that released by six-megaton atom bombs.

The impact was so severe that rocks from all sides came o the surface

and reached the height of 20 meters. The impact was so severe that it

left a massive crater 170 meters deep and with 1800 meter in

diameter. Today it is natural salt-water lake.

The lake was first brought to notice in 1823 by British officer C J

E Alexander. In 1896, American geologist G K Gilbert conducted

studies to prove that Lonar was created due to meteor strike. An

extensive study conducted on the spot under the leadership of Prof. K

Fredrikson by officials of Geological Survey of India, United States

Geological survey and other institutions, proved using Cosmic Ray-

dating that the lake was created by a meteor hit 50,000 years ago.

GEOLOGY OF THE AREA

Geologically, the area belongs to Deccan Basalt formations of

late Cretaceous to early Eocene period. The rocks observed in the lake

are compact, vesicular and amygdaloidal basalt. At places the red bole

beds separated the two lava flows. The basalt flows dip away from the

depression. No appreciable fracturing or shattering is noticeable in the

rocks. Compact basalt rocks are highly jointed and weathered around

the joints. The compact basalt also shows the spheroidal weathering in

the area.

The impact of meteorite yielded the rare mineral called themuskelynite, which is transformed plagioclase feldspar. Around the rim

of crater scattered glass splinters from 10 to 15 cm in length is

observed. These are same like glass pieces and spherules collected by

Apollo astronauts on the moon (India Today 15 August 1979).

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SALINITY OF LAKE WATER

The most striking feature of the lake is its extreme salinity and

high alkalinity (the PH reaches the mark of 10.5 when tested with a PH

paper). The perennial nature of the lake may be due to this high

alkalinity, so that, as evaporation proceeds, the concentration of the

dissolved alkaline matter is increased and, in due course, the

evaporates begin to separate out, which gradually form a more or less

continuous scum over the surface of water, thereby considerably

retarding the rate of subsequent evaporation. The salinity and

alkalinity of this continental, inland lake is attributed to the age of the

lake and also to the mode of formation the crater.

AMBER LAKE

There is a small circular depression, about 700 meters away from

the rim of Lonar crater closely resembling the main crater in its shape

and characteristics. This is known as the Little Lonar and is believed to

have originated from the impact of a smaller piece of the meteor,

which split from the main body, before it hit the ground. The diameter

of this crater is app. 340 meters and rises 6 meters above the ground

level. This crater also has a lake, fed by three streams, which through

the years have eroded the surrounding area causing the exposure of

basaltic breccia. You can find pieces of rock showing typical shock

metamorphosis caused by hypervelocity impact. Although no major

geological research work has so far been done to establish the

meteoritic origin of this depression, this evidences supports such a

thesis and should be considered as an integral part of the precincts of

Lonar crater. In 1973, Fredriksson suggested that Amber lake crater

was formed by a fragment ejected from Lonar crater, whereas S.

Master who surveyed the Amber crater in 1999 concluded that it was

not a secondary crater, but was formed at the same time as the Lonar

crater

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GEOLOGICAL STUDY TOUR REPORT

Submitted to

Department of Geology

Dnyanopasak College

Parbhani - 431 401

As per

Syllabus of

Swami Ramanand Teerth

Marathwada University, Nanded

Submitted by

B. Sc. III Year

GEOLOGY

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For the year

2004-2005

CERTIFICATE

This is to certify that Mr./Miss ____________

_____________________________________________ of B.Sc. III year

(Geology) has attended the geological study tour organised by

Department of Geology, Dnyanopasak College, Parbhani at

Lonar Lake in Buldhana district.

This report covers the geological aspects as per the

B.Sc. standards of syllabus of Swami Ramanand Teerth

Marathwada University, Nanded.

Tour Incharge Head of Deptt. External Examiner

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