Skip to main content

‘Lost continent’ found lurking under Mauritius (hindu, )

Scientists have confirmed the existence of a “lost continent” under the Indian Ocean island of Mauritius that was left over by the breakup of the supercontinent, Gondwana, which started about 200 million years ago.

The piece of crust, which was subsequently covered by young lava during volcanic eruptions on the island, seems to be a tiny piece of ancient continent, which broke off from the island of Madagascar, when Africa, India, Australia and Antarctica split up and formed the Indian Ocean.

“We are studying the breakup process of the continents, in order to understand the geological history of the planet,” said Prof. Lewis Ashwal from University of the Witwatersrand in South Africa.

By studying the mineral, zircon, found in rocks spewed up by lava during volcanic eruptions, Prof. Ashwal and his colleagues have found that remnants of this mineral were far too old to belong on the island of Mauritius.

“Earth is made up of two parts — continents, which are old, and oceans, which are ‘young’. On the continents you find rocks that are over four billion years old, but you find nothing like that in the oceans, as this is where new rocks are formed,” said Prof. Ashwal.

“Mauritius is an island, and there is no rock older than nine million years old on the island. However, by studying the rocks on the island, we have found zircons that are as old as three billion years,” he said.

Zircons are minerals that occur mainly in granites from the continents. They contain trace amounts of uranium, thorium and lead, and due to the fact that they survive geological process very well, they contain a rich record of geological processes and can be dated extremely accurately.

“The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent,” said Prof. Ashwal.

This is not the first time that zircons that are billions of years old have been found on the island. A study done in 2013 has found traces of the mineral in beach sand.

However, this study received some criticism, including that the mineral could have been either blown in by the wind, or carried in on vehicle tyres or scientists’ shoes.

“The fact that we found the ancient zircons in rock (six-million-year-old trachyte), corroborates the previous study and refutes any suggestion of wind-blown, wave-transported or pumice-rafted zircons for explaining the earlier results,” said Prof. Ashwal.

He suggests that there are many pieces of various sizes of “undiscovered continent”, collectively called “Mauritia”, spread over the Indian Ocean, left over by the breakup of Gondwanaland.

“According to the new results, this breakup did not involve a simple splitting of the ancient super-continent of Gondwana, but rather, a complex splintering took place with fragments of continental crust of variable sizes left adrift within the evolving Indian Ocean basin,” Prof. Ashwal added.

Comments

Popular posts from this blog

Cloud seeding

Demonstrating the function of the flare rack that carries silver iodide for cloud-seeding through an aircraft. 
Water is essential for life on the earth. Precipitation from the skies is the only source for it. India and the rest of Asia are dependent on the monsoons for rains. While the South West Monsoon is the main source for India as a whole, Tamil Nadu and coastal areas of South Andhra Pradesh get the benefit of the North East Monsoon, which is just a less dependable beat on the reversal of the South West Monsoon winds.

SC asks Centre to strike a balance on Rohingya issue (.hindu)

Supreme Court orally indicates that the government should not deport Rohingya “now” as the Centre prevails over it to not record any such views in its formal order, citing “international ramifications”.

The Supreme Court on Friday came close to ordering the government not to deport the Rohingya.

It finally settled on merely observing that a balance should be struck between humanitarian concern for the community and the country's national security and economic interests.

The court was hearing a bunch of petitions, one filed by persons within the Rohingya community, against a proposed move to deport over 40,000 Rohingya refugees. A three-judge Bench, led by Chief Justice of India Dipak Misra, began by orally indicating that the government should not deport Rohingya “now”, but the government prevailed on the court to not pass any formal order, citing “international ramifications”. With this, the status quo continues even though the court gave the community liberty to approach it in …

India’s criminal wastage: over 10 million works under MGNREGA incomplete or abandoned (hindu)

In the last three and half years, the rate of work completion under the Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA) has drastically declined, leading to wastage of public money and leaving villages more prone to drought. This could also be a reason for people moving out of the programme.

At a time when more than one-third of India’s districts are reeling under a drought-like situation due to deficit rainfall, here comes another bad news. The works started under the MGNREGA—close to 80 per cent related to water conservation, irrigation and land development—are increasingly not being completed or in practice, abandoned.

Going by the data (as on October 12) in the Ministry of Rural Development’s website, which tracks progress of MGNREGA through a comprehensive MIS, 10.4 million works have not been completed since April 2014. In the last three and half years, 39.7 million works were started under the programme. Going by the stipulation under the programme, close to 7…