“Our findings, when viewed in conjunction with existing data sets, support the existence of ~200 million year cycles in the strength of the Earth’s magnetic field associated with deep Earth processes,” said geomagnetic researcher Dr. Louise Hawkins. Laboratory at the University of Liverpool and CGG Satellite Mapping. “Because nearly all of our evidence for processes within the Earth’s interior is constantly being destroyed by plate tectonics, maintaining this signal deep within the Earth is critical as one of the few limitations we have.”
In the study, Dr. Hawkins and colleagues performed microwave thermal and magnetic analysis on rock samples from two regions of the east coast of Scotland, England. This is similar to a predetermined period of low magnetic field strength that began about 120 million years ago.
The researchers found that between 332 and 416 million years ago, in the so-called Mid-Palaeopolar Low (MPDL) period, the geomagnetic field strength preserved in these rocks was less than a quarter of what it is today. The study supports the theory that the strength of Earth’s magnetic field is periodic, weakening every 200 million years, an idea proposed by Liverpool University professor Andy Begin and his colleagues in 2012.
They also analyzed the reliability of all measurements from samples from 200 to 500 million years ago, which were collected over the last 80 years. They measure the strength of the geomagnetic field over important time periods with virtually no pre-existing reliable data.
The weak field also has implications for life on our planet. In 2020, Professor John Marshall and colleagues from the University of Southampton suggested that the Devonian Carboniferous mass extinction was associated with higher levels of UV-B radiation, about the same as the weakest field measurements from the MPDL. Outlining variations in the strength of the geomagnetic field is important because it shows changes in deep Earth processes over hundreds of millions of years and can provide clues about how they will fluctuate, fluctuate, or otherwise in the future.
“Our findings also provide further support that a weak magnetic field is associated with a pole reversal, whereas the field is generally strong during the Superchron, which is important because it has proven nearly impossible to increase the record reversal 300 million years ago.” “This comprehensive magnetic analysis of Strathmore and Kinghorn pyroclastic flows is key to filling the period before the Cayman Supercron, a period in which Earth’s magnetic poles were stable and did not reverse for approximately 50 million years,” said Dr. Hawkins. “This dataset complements other studies we have worked on over the past few years, together with colleagues in Moscow and Alberta, which are age-appropriate for these two locations.”
Space news highlights
- Title: Study Provides Further Evidence for a 200 Million Year Cycle in the Strength of Earth’s Magnetic Field | geology
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