A Nature journal study published on April 2 challenges long-standing assumptions about Earth’s geological past. Researchers discovered that:
- Earth’s first crust, called the Hadean protocrust, which formed about 4.5 billion years ago, already had chemical traits similar to modern continental crust.
- This challenges the idea that plate tectonics—specifically, subduction zones—were necessary to produce these chemical signatures.
What’s the Big Deal?
For decades, scientists believed:
- The unique chemical fingerprint of continental crust (like low Niobium) resulted from tectonic plates diving beneath one another.
- Therefore, identifying the oldest rocks with this fingerprint would reveal when plate tectonics began—a key clue to understanding early Earth and life’s origins.
But this study found:
- The Hadean protocrust already had these fingerprints naturally, meaning:
- Plate tectonics may not have been necessary at that time.
- The Earth’s early crust could develop these features independently of subduction.
A Hellish Beginning
- During the Hadean eon (first 500 million years of Earth’s history), the surface was:
- Partially molten
- Constantly bombarded by meteoroids
- Volcanically active
- Yet even in this chaos, Earth was forming a crust with modern-like chemistry.
(Source: Scitechdaily)
