Barren Island in Andaman, Â the only active Volcano in India has been estimated to be at least 1.8 Million Years according to a new Study conducted by the Researchers at IIT Bombay and Physical Research Laboratory Ahmedabad.
Researchers used  Argon dating technique to find out the age of the two ash layers older than 42,000 years and generated by this volcano.  The Barren Island volcano, towering some 300 metres above the sea level, has erupted sporadically over the last 70,000 years but it was not known when it had formed and breached the sea surface.
The scientists found that the age of the minerals they studied was older than the age of deposition of the ash layer, which indicates that the minerals were derived from older rocks present in the plumbing system of the volcano. They studied ash layers in a 400-centimetre-long sediment core raised from the Andaman Sea collected from 32 km southeast of the island.
Reliable Argon age of 1.8 million years plagioclase grains separated from the ash layer at a depth of 310 centimetres is surprisingly very much older than its conceivable depositional age of 61,000 years, Jyotiranjan S Ray of PRL reported in Current Science.
The volcano, located about 140 km from Port Blair. The first recorded eruption of the volcano dates back to 1787. It became active in 1991 after lying dormant for 159 years.  Since then, the volcano has erupted more than ten times, with the most recent one which started in September 2010 and continued through January 2011.
After the first recorded eruption in 1787, further eruptions were recorded in 1789, 1795, 1803–04, and 1852. After nearly one and half century of dormancy, the island had another eruption in 1991 that lasted six months and caused considerable damage. There were eruptions in 1994–95 and 2005–07, the latter being considered to be linked to the 2004 Indian Ocean earthquake
Being a stratovolcano, it may have massive eruptions in the future that could seriously affect life in the Andaman Sea, Andaman and Nicobar Islands and neighbouring Southeast Asian countries, the scientists said.
True to its name, it is a barren area uninhabited by humans, though it has a small population of goats. Also birds, bats like flying foxes and a few rodent species such as rats are known to survive the harsh conditions