Research Finds Evidence that the Earth’s Magnetic Field Nearly Collapsed 590 Million Years Ago

OSLO – Earth’s magnetic field it has changed direction many times over millions of years, sometimes accompanied by temporary weakening. A longer period in which this field was reduced occurred between 591 and 565 million years ago.

As reported by Rideapart, not long afterward, complex animal fossils first appeared in the geological record.

A new study suggests that it may be the weakening that allows this to happen, despite the contradiction with the field’s role in making life possible.

The geomagnetic field is one of the things that differentiates Earth from Venus and Mars. This has helped Earth resist atmospheric stripping caused by the solar wind, and acted as a shield against coronal mass ejections that would have flooded the planet with radiation.

The search for life outside the Solar System assumes strong magnetic fields are a requirement, at least for life on the surface rather than deep within planets.

The strength and direction of fields throughout Earth’s history can be read in rocks that preserve a record of local fields at the time they were formed, provided subsequent heat does not erase the bands.

Professor John Tarduno from the University of Rochester and colleagues explored samples of plagioclase crystals from the Passo da Fabiana Gabbros, Brazil, which formed 591 million years ago.

They found evidence of the lowest water levels ever recorded, one-30th of today’s water levels, and also much lower than at any time before.

Based on other research, the authors suggest that fields accounting for less than 10 percent of what exists today persisted for at least 26 million years, including one of the most important periods for life in Earth’s history.