Sand from the beaches of Mauritius contains samples of rocks of the ancient mainland. The flooded remains of an ancient microcontinent seem to scattered under the ocean between Madagascar and India. Photo from open sources find in Mauritius – a volcanic island lying about 900 km east of Madagascar. The oldest basalts there are about 8.9 million years, says geologist Björn Jämtweit from the University of Oslo (Norway). But a thorough sand analysis from two local beaches revealed about twenty zircons – silicate crystals zirconium, which are highly resistant to erosion and chemical changes. They are much older. These zircons formed in granites and other volcanic rocks at least 660 Ma back. One of the crystals is at least 1.97 billion years old. Photos from open sources of
One of the beaches of Mauritius (photo by Ebbe Hartz). Mr. Jamwait and his colleagues suggest that rocks containing these zircons, originated in fragments of the ancient continental crust located near Mauritius. Apparently, relatively recent eruptions volcanoes brought splinters of crust to the surface where zircons found themselves in the sand as a result of erosion. Researchers they also suspect that under the Indian Ocean fragments of that continental crust. Gravitational field analysis Earth has revealed several areas where the oceanic crust is much thicker than usual – 25-30 km instead of the usual 5-10 km. This anomaly may be the remnants of land that scientists suggest calling Mauritia She probably shared with Madagascar, when tectonic riftogenesis and stretching of the seabed forced Indian subcontinent start moving from south indian ocean in a northeast direction. Subsequent stretching and thinning of the cortex in this area led to the lowering of fragments Mauritius, which at that time consisted of an island or archipelago with a total area of about three Crete. Scientists have chosen for analysis sand, not local rocks, to make sure that zircons are inadvertently stuck in crushing equipment after previous research, not contaminated with fresh samples. Nearest continental outcrop the crust, where else you can find the zircons of Mauritius, is deep beneath water. In addition, zircons are mined in places in Mauritius where people hardly come in and could hardly bring them with them. IN the same time the crystals are too large to be delivered there wind. Photos from open sources
Another beach in Mauritius, on which people hardly come (photo by Jack Abuin / ZUMA Press / Corbis). Photo from open sources Color track (see left color scale) west of Reunion is a likely route islands over the past tens of millions of years. Black lines with yellow circles and red circle indicate the path of the African platform and Indian plates respectively. Numbers in circles mean millions years. Areas with topography just below the sea surface are now considered as continental fragments. (Image GFZ / Steinberger.) Research Results Published in Nature Magazine Geoscience. Based on Nature News, Scientists Believe that they found a fragment of a supercontinent beneath the Indian Ocean On bottom of the Indian Ocean, scientists found the remains of an ancient mainland continent that existed 85-2000 million years ago, decided to call Mauritius believed that major changes in the appearance of our planet occurred around 750 million years ago. Before that, there was one huge supercontinent Rodinia. Despite the fact that now India and Madagascar is separated by thousands of kilometers, in those days they are were nearby. Now scientists, writes the journal Nature Geoscience, found the remains of a microcontinent that they thought bound India and Madagascar. An analysis of grains allowed such a conclusion. sand from Mauritius. They date back to about 9 million years, when a powerful volcanic eruption occurred, which threw them to the surface. However, minerals are found in them, which are much older. “In sand we found zircon, says professor at the University of Oslo Trond Torswick, who led the study, which is usually found in continental crust. Moreover, the zircons we have found are very, very ancient. ” Photos from open sources
Scientists believe that they found a fragment of the supercontinent under Indian Ocean Analyzes Show that Zircons May Be 600 – 1970 million years old. Norwegian scientists came to to the conclusion that most likely they are the remains of some very ancient land that the eruption raised to the surface of the island. About 85 million years ago, the BBC quotes the words Professor Torswick, when India began to separate from Madagascar, the microcontinent broke and went under water. Only preserved its insignificant remains, for example, Seychelles.
Water Volcanoes India Islands