Mega eruption key to iron mystery
The research found that mysterious iron formations were deposited at the same time in both North America and Australia, suggesting an eruption caused them. Image: Justinreznick/iStockphoto A superplume, or massive episode of volcanic eruptions that related to extensive melting of the Earth's mantle, could explain the puzzling reappearance of major iron formations long after the rise in atmospheric oxygen about 2.4 billion years ago, according to a study published in Nature today. Oxygen in the atmosphere should have prevented iron forming, and so the presence of the iron formations has long puzzled scientists.The research team, led by Professor Birger Rasmussen of Curtin University, includes Dr Janet Muhling from The University of Western Australia's Centre for Microscopy, Characterisation and Analysis.Iron formations are unique sedimentary rocks composed of iron and silica and are unlike any modern rocks, the study noted. Most iron formations were deposited in the oceans before free oxygen first accumulated in Earth's...