New Study Challenges Prevailing Theory of Earth’s Crust Formation
A recent study conducted by a research team led by Penn State contradicts the prevailing theory of Earth’s crust formation. The study, which analyzed over 600,000 rock samples from around the world, suggests that Earth’s crust has been undergoing a continual slow process of reworking, rather than experiencing a rapid slowdown around 3 billion years ago.
The prevailing theory proposed that there was a sudden shift from a stagnant lid planet with no tectonic activity to the formation of tectonic plates. However, the new research findings challenge this idea and suggest a more gradual growth of the Earth’s crust over billions of years.
The research, published in the journal Geochemical Perspectives Letters, offers valuable insights into planetary formations and differences, particularly concerning Venus. Lead author Jesse Reimink, assistant professor of geosciences, believes that the study may help address fundamental questions about our planet and shed light on the formation of other planets.
To chart the formulation of Earth’s crust, the researchers analyzed a vast database of rock records, comprising more than 600,000 samples. They chose rock records over mineral samples because they are more sensitive and less prone to bias on long time scales. By developing a unique method for determining how igneous rocks reworked and reformed over time, the researchers were able to recreate the crustal growth curve using the rock records.
The team calculated the amount of reworking that had occurred by looking at the composition of igneous rocks in a new way, which allowed them to tease out the proportion of sediments. This data was then used to calibrate the reworking documented in the rock records and calculate Earth’s crustal growth curve.
Reimink and his team found a correlation between the Earth’s crust and the mantle, the layer on which the crust sits. This suggests that the paths of the two are intertwined. While previous studies have suggested a more gradual crustal growth, this study is the first to use rock records to support this idea.
However, Reimink emphasizes that the research is not the definitive answer to crustal growth and that more data is needed to fully understand the vast time and space of Earth’s crust. Nevertheless, further analysis of the existing data points could provide valuable insights into the formation of other planets. For example, Venus, which has no tectonic plates, could serve as a modern-day example of early Earth.
The study was supported in part by the Natural Sciences and Engineering Research Council of Canada. Other contributors to the research include Joshua Davies from the University of Quebec at Montreal, Jean-François Moyen from the University of Lyon in France, and D. Graham Pearson from the University of Alberta in Canada.
In conclusion, the new research challenges our understanding of Earth’s crust formation and offers a more gradual growth curve. It opens doors to further investigations of planetary formations and provides insights into the differences between Earth and other planets like Venus.