Seriously big rocks hit Earth's early life

• Autores: Michael Marshall
• Localización: New scientist, ISSN 0262-4079, Nº. 2982, 2014, pág. 11
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Earth may have been pounded by massive asteroids for a billion years longer than people thought, with the impacts only stopping about 3 billion years ago. If that is true, early life had to endure a bombardment that periodically melted Earth's surface. Donald Lowe and his colleagues have spent 40 years studying a patch of ancient rocks in eastern South Africa called the Barberton Belt. Over 25 years ago they found four layers of spherical particles, which seemed to have condensed from clouds of vaporized rock. Lowe says they are the traces of four major meteorite impacts, and date from between 3.5 and 3.2 billion years ago. Now Lowe's team have described another four layers of spherules from the same period. That means there were eight major impacts within about 250 million years, bolstering the case that the bombardment was still going.