Jun 30, 2018 08:01 AM
https://theconversation.com/the-earths-m...-why-96957
EXCERPT: Underneath our feet, deep down in the Earth, liquid iron is producing the magnetic field that we all take for granted. But every now and then that magnetic field reverses or flips its polarity. What was once magnetic north becomes south – and vice versa. When these reversals take place – and why they do so – has been an enduring mystery.
But our new research shows that there is a relationship between the Earth’s magnetic field and the amount of ancient ocean floor that descends from the surface into the hot ductile mantle beneath, through a process known as subduction. Not only might this relationship give us some idea of how many magnetic field reverses occur over any time period, it also enables us to understand how quickly the mantle (the layer of earth between the crust and the core) moves. [...]
he correlation is not perfect and – even if it were – it would not necessarily imply causation, since a number of potentially confounding factors may be in play. But it is an encouraging result, because it fits with our expectations of how the deep Earth works and gives us a time delay that sits somewhere in the middle of previous estimates. It also makes a unique prediction that, because subduction flux decreased over the past 120m years, reversal rate is predicted to lessen in the next 120m years....
MORE: https://theconversation.com/the-earths-m...-why-96957
EXCERPT: Underneath our feet, deep down in the Earth, liquid iron is producing the magnetic field that we all take for granted. But every now and then that magnetic field reverses or flips its polarity. What was once magnetic north becomes south – and vice versa. When these reversals take place – and why they do so – has been an enduring mystery.
But our new research shows that there is a relationship between the Earth’s magnetic field and the amount of ancient ocean floor that descends from the surface into the hot ductile mantle beneath, through a process known as subduction. Not only might this relationship give us some idea of how many magnetic field reverses occur over any time period, it also enables us to understand how quickly the mantle (the layer of earth between the crust and the core) moves. [...]
he correlation is not perfect and – even if it were – it would not necessarily imply causation, since a number of potentially confounding factors may be in play. But it is an encouraging result, because it fits with our expectations of how the deep Earth works and gives us a time delay that sits somewhere in the middle of previous estimates. It also makes a unique prediction that, because subduction flux decreased over the past 120m years, reversal rate is predicted to lessen in the next 120m years....
MORE: https://theconversation.com/the-earths-m...-why-96957