A study of feldspar crystals found in the oldest igneous rocks of Western Australia has allowed scientists to revise the chronology of Earth's development. The work of an international group of scientists, published in the journal Nature Communications, indicates that the Earth's crust began to actively form much later than previously thought. This is reported by UNN.
Details
The object of study was 3.7-billion-year-old anorthosites from the Murchison region. These rocks are among the oldest on the planet and contain isotopic "fingerprints" of the ancient mantle, which allow tracking the early evolution of the Earth's crust.
Revision of the timing of continental growth
Analysis of plagioclase feldspar crystals showed that the massive growth of continents began approximately 3.5 billion years ago. This is a billion years later than the moment of the formation of the planet Earth itself.
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The timing and rate of early Earth crust growth remain controversial due to the scarcity of very ancient rocks
The use of fine analysis methods made it possible to identify fresh areas of crystals that preserved primary information about the composition of the planet's interior in the Archean era.
The shared past of Earth and Moon
An important part of the study was the comparison of Australian anorthosites with lunar samples collected during NASA's Apollo program. Anorthosites are rare on Earth but make up a significant part of the Moon's surface.
The results of the comparison confirmed that Earth and the Moon had an identical initial composition approximately 4.5 billion years ago. This discovery serves as additional evidence for the Giant Impact theory. According to it, a Mars-sized object crashed into early Earth, and the matter ejected as a result of the impact later formed the Moon.
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