A weakened terrestrial magnetic field during the Ediacaran period, approximately 635 to 541 million years ago, may have played a crucial role in the proliferation of complex life. This is suggested by a new study conducted by researchers at the University of Rochester, published in the journal
Nature Communications Earth & Environment.
This era, marked by the appearance of complex multicellular organisms, appeared to have experienced the weakest magnetic field ever recorded, potentially influencing atmospheric oxygen levels.
Researchers from the University of Rochester studied Earth's magnetic field during the Ediacaran period. This research raises questions about the factors that could have favored the emergence of complex and multicellular organisms, such as the Ediacaran fauna.
Credit: University of Rochester illustration / Michael Osadciw John Tarduno, a professor in the Department of Earth and Environmental Sciences and dean of research, explains that the weakness of the magnetic field could have facilitated the loss of hydrogen into space, thus allowing an increase in oxygen levels in the atmosphere. This phenomenon might have favored the emergence and development of larger and more active forms of life, requiring more oxygen, such as the Ediacaran fauna, known for its similarities with early animals.
Tarduno's team used innovative techniques to measure the strength of the magnetic field by analyzing magnetism preserved in crystals of feldspar and pyroxene from anorthosite rock. These crystals contain magnetic particles that preserve magnetization since the mineral's formation.
The data collected indicates that at times, the magnetic field was up to 30 times weaker than the current magnetic field, and this weakness lasted for at least 26 million years. This discovery suggests that the ultra-weak magnetic field could have contributed to an increased oxygenation of the atmosphere and the surface ocean, thereby facilitating the emergence of more advanced life forms.
The study also highlights the importance of understanding the internal dynamics of planets to consider the potential for life beyond Earth. This research, linking Earth's core processes to the evolution of life, opens new perspectives on the relationship between planetary magnetic fields and biology.