Saturday, November 11, 2006
Rock-solid Support For ‘Snowball Earth’ Theory
CT (USA), 09 November: The main features of the Earth's magnetic field have changed little over the past 2,000 million years, a paper in this week's Nature reports. The finding, which was previously assumed rather than tested, lends support to the 'Snowball Earth' hypothesis.
The Earth's magnetic field leaves a tell-tale signature in certain rocks, which can be used to infer information about the latitude at which they formed. But if the early Earth's magnetic field was markedly different to today's axial dipolar field, some of these interpretations could be off the mark.
David Evans compiled a global database of evaporate rocks extending back through Proterozoic time, over 2,000 million years ago. The rocks' magnetic properties suggest that, as now, the Earth's magnetic field was predominantly an axial dipole on average, suggesting that the Neoproterozoic 'Snowball Earth’ was indeed probably shrouded in ice.
(ResearchSEA)
The Earth's magnetic field leaves a tell-tale signature in certain rocks, which can be used to infer information about the latitude at which they formed. But if the early Earth's magnetic field was markedly different to today's axial dipolar field, some of these interpretations could be off the mark.
David Evans compiled a global database of evaporate rocks extending back through Proterozoic time, over 2,000 million years ago. The rocks' magnetic properties suggest that, as now, the Earth's magnetic field was predominantly an axial dipole on average, suggesting that the Neoproterozoic 'Snowball Earth’ was indeed probably shrouded in ice.
(ResearchSEA)
# posted by mediabhartiwebsolutions @ 5:20 AM 
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