The theory of plate tectonics describes the shifting and interaction of Earth’s vast surface plates. However, new evidence suggests that mobile plate tectonics, believed to be crucial for fostering a habitable planet, was not active on Earth 3.9 billion years ago. Credit: University of Rochester illustration / Michael Osadciw
A collaborative research initiative reveals that the Earth’s magnetic field was steady from 3.9 to 3.4 billion years ago, coinciding with the proposed time for the dawn of life. This stability implies that continents were stationary rather than undergoing plate tectonics, questioning the assumption that mobile plate tectonics are vital for life’s inception.
Florida State University (FSU) faculty member’s investigation contributes significantly to the understanding of the conditions needed for life’s advent on Earth.
FSU Assistant Professor Richard Bono was a key member of a multi-institution team that discovered the Earth’s magnetic field stability from 3.9 to 3.4 billion years ago, a period associated with the possible first emergence of life. The research was featured in the esteemed journal Nature.
Bono further elaborated on the team’s discoveries and their implications for the beginnings of plate tectonics and life on Earth.
Florida State University Assistant Professor Richard Bono. Credit: Florida State University
Research Discoveries:
The team’s research demonstrated that Earth’s magnetic field remained steady from 3.9 to 3.4 billion years ago, aligning with the age of the oldest known fossils. In contrast to previous studies focused on a single location, this investigation involved examining magnetic carriers in the mineral zircon from two distinct ancient continental masses. The results infer that the magnetic field was uniform for over half a billion years. This persistent field aligns with the concept of stationary continents, which challenges the long-held belief of continuous plate tectonics, thus helping us understand when mobile plate tectonics might have begun.
Significance of the Study:
Plate tectonics is widely considered a cornerstone in facilitating life on Earth. The contemporary arrangement of continents and oceans, including supercontinents like Pangea, owes to plate tectonics. Through the formation and degradation of the rocky crust, plate tectonics presumably regulate the elemental cycle essential for life. However, the onset of mobile plate tectonics is still a mystery. If life first arose approximately 3.8 billion years ago, it would have coincided with a period of tectonic stagnancy. This revelation challenges the assumption that modern mobile plate tectonics are obligatory for life’s origin, broadening our perspective on planetary habitability.
Expansion of Existing Knowledge:
Earlier studies provided evidence for an Earth-originating magnetic field as far back as 4.2 billion years ago, with data sourced solely from Australia. This study incorporates data from an additional continent, allowing for the investigation of relative field strength variations from different locales, thus offering clues about potential plate movements.
Research Methodology:
The team analyzed rock samples collected from expeditions to Australia and South Africa, particularly focusing on zircon grains less than a millimeter in size. The magnetization strength of the samples was measured in a magnetically shielded laboratory at the University of Rochester by heating the grains with a laser and noting the magnetization change using an ultra-high sensitivity magnetometer. The ages of individual zircon grains were determined at the Geological Survey of Canada employing a high-resolution ion microprobe.
Armed with this new data, the team was able to conduct novel statistical analyses and compare the results with existing plate motion models. The observations from this fresh dataset could not be justified by regular variations in the plate tonic processes active for the last 600 million years or so.
Who Contributed to this Research?
This research was a joint venture led by University of Rochester Professor John Tarduno, with co-authors from the Geological Survey of Canada, University of California Santa Cruz, University of Johannesburg, University of the Witwatersrand, University of Arizona, University of KwaZulu-Natal, and the Geological Survey of Japan. The National Science Foundation funded the research.
For more on this research, refer to the article Life Sprung From a “Stagnant Lid,” Not Plate Tectonics.
Reference: “Hadaean to Palaeoarchaean stagnant-lid tectonics revealed by zircon magnetism” by John A. Tarduno, Rory D. Cottrell, Richard K. Bono, Nicole Rayner, William J. Davis, Tinghong Zhou, Francis Nimmo, Axel Hofmann, Jaganmoy Jodder, Mauricio Ibañez-Mejia, Michael K. Watkeys, Hirokuni Oda, and Gautam Mitra, 14 June 2023, Nature.
DOI: 10.1038/s41586-023-06024-5
Table of Contents
Frequently Asked Questions (FAQs) about Plate Tectonics and Life’s Origin
What does the new research about Earth’s magnetic field suggest?
The research indicates that Earth’s magnetic field was stable from 3.9 to 3.4 billion years ago, suggesting that continents were stationary rather than undergoing plate tectonics. This challenges the existing belief that mobile plate tectonics are essential for life’s emergence.
Who conducted this new research about plate tectonics and life’s origin?
The study was a multi-institutional effort led by University of Rochester Professor John Tarduno, with co-authors from various institutions including the Geological Survey of Canada, University of California Santa Cruz, University of Johannesburg, University of the Witwatersrand, University of Arizona, University of KwaZulu-Natal, and the Geological Survey of Japan. The research was funded by the National Science Foundation.
How does this study challenge the role of plate tectonics in the emergence of life?
This study suggests that life could have emerged during a period of tectonic stagnation or when continents were stationary, challenging the long-held belief that continuous or mobile plate tectonics are necessary for life’s origination.
How was the research conducted?
The team analyzed rock samples collected from Australia and South Africa. The strength of the sample’s magnetization was measured in a magnetically shielded laboratory at the University of Rochester. The ages of each zircon grain were measured at the Geological Survey of Canada using a high-resolution ion microprobe.
What does this study contribute to our understanding of Earth’s history?
This study offers fresh insights into the conditions necessary for the emergence of life, suggesting that life may have originated during a period of tectonic stagnation. It also expands our knowledge about the Earth’s magnetic field and its stability over half a billion years ago, which was inferred from data sourced from two separate ancient continental masses.
More about Plate Tectonics and Life’s Origin
- Origins of Life and Plate Tectonics
- Plate Tectonics and the Evolution of Life
- Florida State University’s Research
- University of Rochester Earth and Environmental Sciences
- National Science Foundation
- Geological Survey of Canada
5 comments
This kind of research is why I love geology! It’s like a detective story, but the clues are billions of years old. Very cool.
im no scientist but i love reading about these things. Earth’s history is way more complex than i thought!
This is fascinating stuff! The fact that life might have sprung up during a period of tectonic stagnation blows my mind. Keep up the good work guys.
woah, never thought of it like that. Always figured plate tectonics were a must for life, good to know we still got lots to learn.
Amazing how much we can learn from rocks and magnetism! and to think that continents might’ve been stationary when life first emerged, its a total paradigm shift!