A weak magnetic field may have contributed to the diversification of life on Earthaccording to an article published in Communications Earth & Environment.
The authors propose that weakening of the magnetic field may have led to increased oxygenwhich is believed to supported the evolution of some of the first complex organisms.´
They find the oldest indisputable evidence from 3.7 billion years ago of the Earth’s magnetic field
Novel theory
ago 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 diversified significantly in complexity and type between 575 and 565 million years ago. Previous research has suggested that this diversification is related to a significant increase in atmospheric and oceanic oxygen levels which occurred during the same period. However, it is still unclear why this increase in oxygen occurred.
The investigator John Tarduno and their colleagues analyzed the magnetic properties of 21 plagioclase crystals, a common mineral in the Earth’s crust, which were extracted from a 591 million year old rock formation in Brazil. Plagioclase crystals contain small magnetic minerals that preserve the intensity of the Earth’s magnetic field at the time they form.
Analysis of the crystals showed that at their point of formation, Earth’s magnetic field was the weakest ever recorded: about 30 times weaker than the current magnetic field intensity and that measured in similar crystals formed approximately 2 billion years ago.
The authors combined their results with previous measurements to establish that Earth’s magnetic field was at this weak level for at least 26 million years, 591 to 565 million years ago. This overlaps with the increase in oxygen, which occurred between 575 and 565 million years ago.
The authors propose that The weakened magnetic field may have allowed more hydrogen to escape into space, resulting in a higher percentage of oxygen in Earth’s atmosphere and oceans.a, which in turn could have favored the diversification of the types and complexity of the organisms.
Reference
John Tarduno, Near-collapse of the geomagnetic field may have contributed to atmospheric oxygenation and animal radiation in the Ediacaran Period, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01360-4.
This entry was published in News on 05 May 2024 by Francisco Martín León
