The diversity of life on Earth may have occurred due to a weak magnetic field millions of years ago.

A weak magnetic field may have contributed to the diversity of life on Earthaccording to an article published in Connection Earth and environment.

The authors suggest that weakening of the magnetic field could lead to an increase in oxygen contentwhat is believed to be supported the evolution of some of the first complex organisms.´

New theory

back between 600 and 540 million years ago, life on Earth consisted of soft-bodied organisms. known as Ediacaran fauna, the first known complex multicellular animals. The fossil record shows that These organisms changed significantly in complexity and type between 575 and 565 million years ago.. Previous studies have shown that this diversification is associated with significant increase in oxygen levels in the atmosphere and ocean happened during the same period. However, it is still unclear why this increase in oxygen occurred.

Investigator John Tarduno and their colleagues analyzed magnetic properties of 21 plagioclase crystals, a common crustal mineral that was extracted from a 591-million-year-old rock in Brazil. Plagioclase crystals contain small magnetic minerals which maintain the strength of the Earth’s magnetic field at the time of their formation.

Analysis of the crystals showed that at the moment of their formation The Earth’s magnetic field is the weakest in history: About 30 times weaker than current magnetic field strengths measured in similar crystals formed about 2 billion years ago.

The authors combined their results with previous measurements to establish that The Earth’s magnetic field has been at this weak level for at least 26 million years., 591–565 million years ago. This coincides with the increase in oxygen that occurred between 575 and 565 million years ago.

The authors suggest that The weakened magnetic field may have caused more hydrogen to leak into space, causing more oxygen in Earth’s atmosphere and oceans.a, which in turn could contribute to the diversity of types and complexity of organisms.

Link

John Tarduno Near-collapse of the geomagnetic field may have contributed to atmospheric oxygenation and animal radiation during the Ediacaran period, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01360-4.