Wednesday 20 November 2013

The Pyroclasts of Peddapalli

India has a variety of tourism circuits. They include historical, pilgrim, Nature, wildlife and even medical tourism and in Mumbai there is the slum tourism which takes you to Dharavi, the largest slum in Asia and possibly even the world.
However, there is one sector where the tourism potential has not been tapped. This is the Geological sites that are available in plenty in India and Karnataka is fortunate in having four of them. Of them one is right in Bangalore city and another is near the metropolis. The other two are a little far away.
The first is of course the famed rock in Lalbagh botanical gardens and the Bugle rock in Basavanagudi. Both the rock formations are millions of years old and both are of immense geological value.
But did you know that another little known wonder of Bangalore is that it sits atop a rock and this is called gneiss.
Another geological wonder is the Pyroclastic rocks of Peddapalli near Kolar, which is a little more than 75 kilometers from Bangalore.
The third geological wonder is the Pillow lava formations in  Maradihalli near Chitradurga. The fourth geological monument of national importance is the Columnar basaltic lava on St.Mary's Island near Udupi in Arabian Sea.
Since, an earlier post has already dealt with both the rocks at Lalbagh and Bugle Rock, let us go to the geological rock formations in Kolar district.
Kolar district adjoins Bangalore district and from times immemorial it has been known as the land of gold. Kolar and its surroundings are historically important. It is also the district with a large number of pilgrim places.
Today, thousands of people travel through the district on the way to Tirupathi-Tirumala bit few know the jaw-sagging rocky outcrops that we see when we enter the district is more than a picture postcard.
The rock formations at Peddapalli near Kolar have been declared as a natural or geological wonder by the Geological Survey of India (GSI). But apart from budding geologists and Earth scientists, few know of the importance of this unique rock formation.
Peddapalli is a small village  about 700 meters east of the road connecting Kolar Gold Field with the Bangarpet- Betmangala.
There is signboard put up by the Geological Survey of India (GSI) leading to the rock formation and it can be best approached by driving towards the southerly diversion near the 10 km stone for about one kilometer.
The rocky outcrop of pyroclasts is on the north west corner of the village. Pyroclastic Pyroclasts is also called as tepra  (It is a Greek word for ash) and they are nothing but volcanic fragments that was hurled through the air by volcanic activity that took place here several millions of years ago.
The explosions could have been one or many and such rocks would have hardened over a period of several million years. A  pyroclastic rock is a hardened, solidified or compressed version of an originally loose pyroclastic deposit that was thrown up in air and fell in a heap on the ground and subsequently solidified.
The word pyroclastics is derived from a Greek word meaning fire. This is reference to the red hot lava that comes out a volcano. Thus the term pyroclastic means broken by fire.
If the volcanic rocks has been transported and reworked through mechanical action either by wind or water, they are then called volcaniclastic.
By the way, even ash is considered to be pyroclast as even it is a form of  fine dust made up of volcanic rock.
These pyroclast thrown up by a volcano vary in size and composition. However, all these ejected material consolidate to form pyroclastic rocks.
The smaller rocks is known as lapilli, while bigger sized rocks are called as volcanic bombs or blocks. Some of the bigger rocks are known to weigh thousands of pounds. Some rock fragments of granite gneiss found in Peddahali measure upto 80 cm in diameter
The GSI says the Pyroclastic rocks of Peddapalli is a welded rock of large fragments of granite, granite gneiss, basalt and banded ferruginous quartzite which is set in a matrix of ignimbrite. While many rock fragments are angular, some of them are round in shape.

Check out the natural rock formation. It will help us understand the history of the Earth where we all live.

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