It is very well known that solid rock is the main component for earth's mantle which slowly circulates over millions of years. Geologists assumed that this slow circulation results in the wiping away of any geochemical traces of earth slowly. But this assumption has been proved wrong by a new study which is led by University of Maryland regarding young volcanic rocks.
As written in Phys.org, in the study which has been led by the University of Maryland, the researchers have discovered new evidence which can be very much old, more than 4.5 million years ago. The study has been performed on the volcanic rocks which were erupted from volcanoes in Hawaii and Samoa recently. Surprisingly, these rocks contain geochemical anomalies which are of the time, when the earth was formed.
The research paper published in the Journal Science on 7 April clearly mentions about the fingerprints, the geochemical anomalies, which existed at the time when the planet was formed. The reason has not been confirmed that how these anomalies still preserved and have not been wiped away from the volcanic rocks.
The University of Maryland reported that in the volcanic rocks, the anomalous fingerprints have been discovered in the ratios of key isotopes of mainly two elements, i.e. tungsten and helium. The important ratios of tungsten are tungsten 182 and tungsten 184. Being heavier, tungsten 184 is more stable and has been existed since the formation of the planet.
Tungsten 182 is highly unstable and is formed by the decaying of hafnium 182. For the first 50 million years, hafnium 182 decayed leaving behind tungsten 182. The volcanic rocks contained both the ratio, i.e. tungsten 182 and tungsten 184. Geologists can now study how much hafnium 182 was present in the rock in previous years long ago through the anomalies.
Helium-3 is found rarely on Earth but these volcanic rocks have traces of helium-3 making it possible that either these samples of rock have not been melted or recycled since the formation of Earth. This was also proved in the study that the volcanoes are taking up materials from the earth's core, where it is expected to have low ratios of tungsten 182 and high ratios of helium-3. This discovery can lead to new research opportunities for Earth's history.
