An investigation into feldspar crystals found in the oldest magmatic rocks in Australia has unveiled important details about the early Earth and the moon”s formation. The research, led by Ph.D. student Matilda Boyce from the University of Western Australia, involved collaboration with experts from UWA”s School of Earth and Oceans, the Geological Survey of Western Australia, and Curtin University. The findings were published in the journal Nature Communications.
The team studied anorthosites that are approximately 3.7 billion years old, located in the Murchison region of Western Australia. These rocks represent some of the oldest geological formations on the continent and on Earth itself. Boyce noted, “The timing and rate of early crustal growth on Earth remains contentious due to the scarcity of very ancient rocks.” To investigate this, researchers employed advanced analytical techniques to isolate pristine sections of plagioclase feldspar crystals that capture the isotopic signature of the ancient mantle.
The analysis revealed that continental growth began relatively late in Earth”s history, around 3.5 billion years ago, which is roughly 1 billion years after the planet”s formation. Additionally, the study compared these findings with data from lunar anorthosites collected during NASA”s Apollo missions. “Anorthosites are rare on Earth but prevalent on the moon,” Boyce explained. “Our findings align with the idea that Earth and the moon shared a similar initial composition around 4.5 billion years ago.”
This research lends credence to the hypothesis that a massive impact event involving a different celestial body contributed to the formation of the moon. The isotopic analysis of these ancient rocks provides a clearer picture of the processes that shaped both our planet and its lunar companion.
For further details, refer to: Matilda Boyce et al, “Coupled strontium-calcium isotopes in Archean anorthosites reveal a late start for mantle depletion,” Nature Communications (2025). DOI: 10.1038/s41467-025-64641-2.
