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Study: Fragments Of Continents Hidden Under Lava In The Indian Ocean
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POTSDAM, Germany -- The islands Reunion and Mauritius, both well-known tourist destinations, are hiding a micro-continent, which has now been discovered. The continent fragment known as Mauritia detached about 60 million years ago while Madagascar and India drifted apart, and had been hidden under huge masses of lava. Such micro-continents in the oceans seem to occur more frequently than previously thought, says a study in the latest issue of Nature Geoscience ("A Precambrian microcontinent in the Indian Ocean," Nature Geoscience, Vol 6, doi: 10.1038/NGEO1736).

The break-up of continents is often associated with mantle plumes: These giant bubbles of hot rock rise from the deep mantle and soften the tectonic plates from below, until the plates break apart at the hotspots. This is how Eastern Gondwana broke apart about 170 million years ago. At first, one part was separated, which in turn fragmented into Madagascar, India, Australia and Antarctica, which then migrated to their present position.

Plumes currently situated underneath the islands Marion and Reunion appear to have played a role in the emergence of the Indian Ocean. If the zone of the rupture lies at the edge of a land mass (in this case Madagascar / India), fragments of this land mass may be separated off. The Seychelles are a well-known example of such a continental fragment.

A group of geoscientists from Norway, South Africa, Britain and Germany have now published a study that suggests, based on the study of lava sand grains from the beach of Mauritius, the existence of further fragments. The sand grains contain semi-precious zircons aged between 660 and 1970 million years, which is explained by the fact that the zircons were carried by the lava as it pushed through subjacent continental crust of this age.

This dating method was supplemented by a recalculation of plate tectonics, which explains exactly how and where the fragments ended up in the Indian Ocean. Dr. Bernhard Steinberger of the GFZ German Research Centre for Geosciences and Dr. Pavel Doubrovine of Oslo University calculated the hotspot trail: "On the one hand, it shows the position of the plates relative to the two hotspots at the time of the rupture, which points towards a causal relation," says

Steinberger. "On the other hand, we were able to show that the continent fragments continued to wander almost exactly over the Reunion plume, which explains how they were covered by volcanic rock." So what was previously interpreted only as the trail of the Reunion hotspot, are continental fragments which were previously not recognized as such because they were covered by the volcanic rocks of the Reunion plume. It therefore appears that such micro-continents in the ocean occur more frequently than previously thought.

Views expressed in this article do not necessarily reflect those of UnderwaterTimes.com, its staff or its advertisers.

Reader Comments

2 people have commented so far. cloud add your comment

Personally a fantastic find and in the same token places Like Aldabra Atoll is another area worth looking,as the Russian did Seismic Survey in the early 50's and so many Hot Spot and Mantles were recorded and the Atlas they produce is evidence in the Aldabra Research Station. Congratulation to all involved. Guy
   comment# 1   - Guy Patrice Esparon · Intendance.Mahe Seychelles Island · Feb 25, 2013 @ 10:13pm

This is an excellent discovery. Zircon is an accessory mineral in continental rocks mainly in the upper mantle. Can this assumed as the Mauritius continental rock adequately support life in the near future? This is in account of live basics without immediate import of soil! Thank you.
   comment# 2   - Peter Mbevo · Kenya · Feb 26, 2013 @ 12:26am
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