“Reversals are produced within the deepest parts of the Earth’s core. However, the results manifest themselves through the Earth and particularly at the Earth’s surface and within the atmosphere,” mentioned lead author Dr. Brad Singer, a geologist at the University of Wisconsin-Madison.
“Until you have an entire, accurate and high-resolution record of what a field reversal is like at the surface of the Earth, it’s tough even to discuss what the mechanics of producing a reversal are.”
For the research, Dr. Singer and his colleagues centered on a lava flow from Chile, Tahiti, Hawaii, the Caribbean, and the Canary Islands. They collected samples from these lava flows over several field seasons.
“Lava flows are perfect recorders of the magnetic discipline. They have several iron-bearing minerals, and when they cool, they lock within the direction of the field,” he defined.
“However it’s a spotty record. No volcanoes are repeatedly erupting. So we’re relying on careful fieldwork to establish the best records.”
The researchers combined magnetic readings and radioisotope dating of samples from seven lava flow sequences to recreate the magnetic field over about 70,000 years centered on the latest geomagnetic reversal.
They precisely dated the lava flows by measuring the argon produced from radioactive decay of potassium within the rocks.
They discovered that the ultimate reversal was quick by geological requirements, less than 4,000 years.