LONDON:- Scientists have tracked the “family history” of a rock back to some of the earliest times on Earth. Researchers analysed the concentration and distribution of particular types of atoms in the granite to show it must have been recycled from something that existed 4.2 billion years ago. This “parent rock” was very probably basalt of the sort produced on the ocean floor, they say. The team reports its work in this week’s Science Magazine. With most rock on Earth being broken down by weathering or taken back into the planet’s interior just a few hundred million years after production, there is very little, truly ancient material to look at.–BBC

 Geological genealogy offers a very useful alternative in the circumstances, says Dr Jonathan O’Neil from the University of Ottawa, Canada.