Also lead to rapid evolution, which I’ve been saying for years.
A new study proposes that the devastating mass extinction at the end of the Ediacaran Period can be connected to rapid reversals in the Earth’s magnetic field.
Geologist Joseph Meert of the University of Florida in Gainesville and his colleagues think the rapid reversals destroyed much of the ozone layer, thus allowing a flood of ultraviolet radiation onto our planet.
Prior to that extinction, large, soft-bodied creatures up to a meter (3.3 feet) across resided beneath a thick, slimy mass of bacteria on the seafloor. Then suddenly, at what is known as the “Cambrian explosion,” a multitude of more complex animal groups inexplicably appear in the geologic record. Opabinia , for example, had five eyes.
Scientists have long argued over what caused the Cambrian explosion, an evolutionary event beginning around 542 million years ago during which most major animal phyla appear in the fossil record.
Meert’s team found evidence (now in press in Gondwana Research) that the reversal rate during the Ediacaran Period was 20 times faster than today. “Earth’s magnetic field underwent a period of hyperactive reversals,” says Meert.
Previous research has suggested that Earth’s protective magnetic field shields life from harmful solar radiation and cosmic rays.
However, the magnetic field would be weaker during periods of frequent reversals. With the shield weakened, ever more high-energy particles would penetrate the planet’s upper atmosphere, which, in turn, would double the amount of UV radiation reaching Earth’s surface.
Many evolutionary changes that occurred during that era could be explained in this way, says Meert.
Vindication! This, of course, is what I’ve been saying for years. I think the weakened magnetic field allows mutation-causing radioactivity to bathe our planet, leading to evolutionary leaps. (See both Not by Fire but by Ice and Magnetic Reversals and Evolutionary Leaps.
“Rapid changes of magnetic Field polarity in the late Ediacaran: Linking the Cambrian evolutionary radiation and increased UV-B radiation”
“Hyperactive magnetic field may have led to one of Earth’s major extinctions” http://www.sciencemag.org/news/2016/02/hyperactive-magnetic-field-may-have-led-one-earth-s-major-extinctions
Thanks to John Zielinski for these links