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
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