Prof. (Dr) YP Kundal
Broadly, meteorites are divided into three categories on the bases of composition i.e. stony, iron -stony and iron-Ni. The first represents the crustal part of the shattered planet in the space, second the mantle and third one, the core. The first one is the lightest in weight and colour, whereas, the last one is the darkest and the heaviest. The formation of impact craters is achieved in three steps, namely compression, excavation and modification.
When an asteroidal or meteoroidal object hits the earth, it is traveling typically at several tens of kms/second and many many times the speed of the sound. A collision at such extreme speeds is called a hypervelocity impact. Although the resulting depression may bear some resemblance to the hole that results from throwing a pebble into clay or sand-box, the results are actually much closer to that of an atomic bomb explosion.
Formation and types of Impact Craters.
As the nature of earth`s crust, target rocks, gravity, atmospheric pressure and its composition has not always been the same throughout the evolutionary history of earth and accordingly, the nature of meteoroids, their velocity, the amount of atmospheric resistance and the angles of hitting have also not remained the same throughout the impacting history of meteoroids. Therefore, the natures of impact signatures marked on the surface of earth are always supposed to vary from time to time and place to place.
The Somnath Sarovar, diameter 580 mt. The crater was formed by a meteoritic fragment of appx 30 mt diameter. The central high and the crater rims are well preserved.
The Kankariya Lake,diameter 600 mt isa circular lake . The central high and the rims are well intact. The isthmus is created by the earlier rulers.
The Chandola Lake dia 950 mt is a circular lake.The central high and the crater rims are well intact.
The Naroda Lake, a circular lake,dia 250 mt has a well preserved central high and crater rims.
The Vadsagar Lake, the central high and rims are intact.
The Samayalapura Lake, It is a circular lake, a simple type of crater.
Vaghel impact crater/lake- Shows a well developed central high, Impact Rays and Rims surrounded by the scatterd ejecta blanket.
The small dark spots in the crater are the secondary impacts formed by the fall of ejecta blanket.
The concentric rings around the central high show the proof of slow upliftment.
The Pavagarh Hills show the impact scars along the slopes and crater lakes (Dudhiya ,Teliya etc) on the top.
Evidences in favour of impacts
1/ The Morphological evidence—The circular lakes, with islands and raised rims can`t be expected to form by any other process on a geologically young and plain surface. The raised rims and pulverised soil mixed with eject-blanket surrounding the crater are the confirmations.
2/ The dark black “Shivlingams”(meteorites) symbolic of Lord Shiva are the holy stones idols of worship, which were very hot at the time of their fall, have since been showered to keep them cool.
3/ The Proof of Shock metamorphism- The Narmadeshwars Shivlings collected/ sculptured from the river bed of Narmada represent the shock metamorphosed products of cataclastic forces called as impactites.
Natural Impactite
The Narmadeshwar Shivling
4/ The Religious Proof– The Indus Valley Civilization people, bronze age civilisation, our ancestors whom we have inherited the concept of Lord Shiva, Shivlingam and Jyotrilingams have given us a very strong evidence in favour of meteoritic shower they had actually seen with their own eyes. That’s why the description of “Jyotrilingas-the pillars of fire” pierciing the three worlds, “Trilouki” i.e. the Akaash-Dharti-Pataal, describes the Tandava of Lord Shiva that had destroyed the entire Indus-Valley civilization. The pillars of fire were actually the tails of falling asteroids and after hitting the Dharti, pierced the crust and became invisible.
5/ The recital “AOM” Mantra-The vibrations produced by the fall of those extra-terrestrial objects/fire-balls have been well preserved in the verbal sound/echo of word “AUM” Mantra, narrated by saints as the “sound of universe”.
6/ Historical and Archeological Proof-The actual cause of extinction of Indus-Valley Civilisation, hitherto unknown by the historians is also linked with the meteoritic showers. Some of the implements recovered from the sites are made of iron meteorites.
Since, the Shiva Temples are always located alongside the lakes called as “Kunds”, it is also proposed that all such Kunds/lakes and the famous temples of Jyotirlingas with deities made up of meteorites located all over the country/world are actually the sites of impacts.
The ‘Berringer Meteor Crater in Arizona’ is just a small and dry crater and is the only crater site in Arizona and millions of tourists visit the impact site to feel the beauty of celestial phenomenon, while in India (Gujarat), we have thousands of such like sites and that too of bigger diameters with crystal clear water, it’s the demand of the time to tell the world about this heavenly treasure. I am sure, hearing and reading this news, millions of people from all over the world would certainly flock to the state of Gujarat to have the first hand experience of walking along the crater lakes and then swimming in the crater lakes.
(The author is Former Head of PG Dept of Geology GGM Sc College Jammu & Principal GDC Mahanpur but now in RUSA)