Why in the News?

Geologists have reconstructed a massive and previously unknown tectonic plate that was once one-quarter the size of the Pacific Ocean.

About Pontus Tectonic Plate:

• Recently discovered in the west Pacific Ocean, the Pontus Tectonic Plate is a long-lost geological plate that holds significance in Earth's history.
• Believed to have measured about 15 million square miles at its zenith, roughly equivalent to one-quarter of the Pacific Ocean, this massive tectonic plate dates back as far as 160 million years, with more recent traces extending to approximately 20 million years ago.
• Over millions of years, the Pontus Plate underwent a gradual subduction process, pulled downward beneath a neighbouring plate by the force of gravity.

How was this Discovery Made?

• The subducting process involves the plate sinking into Earth's mantle due to its higher density compared to the surrounding mantle.
• Traces of a subducted plate are discernible in the form of rock fragments concealed in mountain belts.
• During subduction, upper portions of the plate are occasionally scraped off.
• Researchers employed geological data and computer modelling to reconstruct the movements of current plates, revealing a substantial area potentially vacated by the subducted Pontus Plate.
• Utilizing magnetic techniques, scientists identified basalt remnants in Borneo as Pontus relics, suggesting that this fragmentary evidence was left behind during the plate's subduction some 85 million years ago.

What is Plate Tectonics?

• Tectonic plates are large, rigid pieces of Earth's lithosphere, the outer shell comprising the crust and uppermost part of the mantle.
• These plates, which vary in size and shape, constantly move and interact, shaping the Earth's dynamic surface.
• The Earth's lithosphere is divided into several major plates, such as the Pacific, North American, and Eurasian plates, among others.
• The interactions at plate boundaries result in various geological phenomena, including earthquakes, volcanic eruptions, and the formation of mountain ranges.
• Plate tectonics, the theory explaining these movements, underscores how heat-driven convective currents in the Earth's mantle cause plates to diverge, converge, or slide past each other.
• Tectonic plate movements influence the planet's topography, seismic activity, and the distribution of continents and oceans, playing a fundamental role in Earth's geological evolution.