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- According to scientists, tectonic activity began on Earth 3.3 billion years ago. It was previously assumed that tectonic activity began about 2.7 billion years ago on Earth.
- The conclusion came from scientists after they studied a microscopic bead of cooled magma which was protected by it olivine crystal.
- The olivine crystal was found in a komatiite rock, named after the Komati River in South Africa.
- Komatite rocks were formed when extraordinarily hot plumes of magma rose from the mantle to Earth’s surface during the Archaean period (2.5 billion to 4 billion years ago).
- The scientists found that the microscopic bead of cooled magma contained a number of signatures of subducted oceanic crust. They concluded the magma originated in the melted remains of an ancient ocean seafloor indicating that plate tectonics started nearly 3.3 billion years ago.
- The theory of plate tectonics proposes that the earth’s lithosphere is divided into seven major and some minor plates which are floating over the asthenosphere. All tectonic activities occur along the margins of these plates e.g. seismic events, vulcanicity, mountain building, faulting etc.
