Monday, 19 December 2011

Krisna’s Butter Ball

Krisna’s Butter Ball is but one of many attractions within Mamallapuram or Mahabalipuram which is a tourist town 60 km south of Chennai made famous by its granite stone carvings.


Locally one may find many famous stone carvings, the most famous of which is the Shore Temple, which was saved from the sea and subsequently excavated and has become one of the most beautiful locations in the region. (Note: The area around Mamallapuram was devastated by the 2004 Indian Ocean tsunami: you will see shanty-towns built for affected fishermen and much of the greenery has been swept away.)

There are no documented legends attached to how Krisna’s Butter Ball came to rest in this particularly precarious position. From one angle, this free-standing granite stone appears to have sheared off some larger formation, but there is no evidence of any nearby location where it might have originated.

Could the stone have come to find itself here, transported by some glacial activity or even possibly the result of ice age erosion?

Glacial Erosion is the wearing-down and removal of rocks and soil by a glacier. Glacial erosion forms impressive landscape features,including glacial troughs (U-shaped valleys), aretes (steep ridges), corries (enlarged hollows), and pyramidal peaks (high mountain peaks with three or more aretes).

Erosional landforms result from abrasion and plucking of the underlying bedrock. Abrasion is caused by the rock debris carried by a glacier, wearing away the bedrock. The action is similar to that of sandpaper attached to a block of wood. The results include the polishing and scratching of rock surfaces to form powdered rock flour, and scratches or striations which indicate the direction of ice movement. Plucking is a form of glacial erosion restricted to the lifting and removal of blocks of bedrock already loosened by freeze/thaw activity.

The most extensive period of recent glacial erosion was the Pleistocene epoch (1.6 million to 10,000 years ago) in the Quaternary period (last 2 million years) when, over a period of 2 to 3 million years, the polar icecaps repeatedly advanced and retreated. More ancient glacial episodes are also preserved in the geological record, the earliest being in the middle Precambrian era(4.6 billion to 570 million years ago) and the most extensive in Permo-Carboniferous times.

Additional References:

Glacial Erosion -http://www.geography.learnontheinternet.co.uk/topics/glaciation1.html#erosion

http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0035305.html

Wikipedia (Glacier) - http://en.wikipedia.org/wiki/Glacier

Erosional Processes -http://gemini.oscs.montana.edu/~geol445/hyperglac/eroproc1/

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