With tectonic plates bumping and grinding against each other, Earth is a pretty active planet. Principles of plate tectonics.

Tectonic plates are large slabs of rock embedded in the Earth’s crust and upper mantle, the next layer down. New tools to model and visualize subduction zones in 3-D are providing researchers with insights into the gaps inherent in the theory of plate tectonics. Plate tectonics is the unifying theory of geology, said Nicholas van der Elst, a seismologist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York. An enduring question in geology involves the question of when the tectonic plates of the Earth’s crust began pushing and pulling in a process that formed the planet’s continents, oceans, and other landforms. A giant tectonic plate under the Indian Ocean, known as the India-Australia Capricorn plate, is breaking apart at about 1.7 mm (0.07 mm) per year, according to a new study. Major Tectonic Plates By Size Pacific Plate - 103,300,000 sq km The Pacific Plate is estimated to be 103,300,000 square kilometers in size. Over a much longer period, the same process could have created many tectonic plates, says co-author David Bercovici, a geophysicist at Yale University in New Haven, Connecticut. Some researchers theorize it happened about 4 billion years ago. Slab pull is the most relevant force that affects the movement of tectonic plates. A new study has revealed a new tectonic microplate — there are now 57 in total. Such movements can trigger millions of years of devastating earthquakes. Together, these plates constitute the lithosphere, from the Greek lithos, meaning “rock.” Earth’s surface layer, 50 to 100 km (30 to 60 miles) thick, is rigid and is composed of a set of large and small plates. Tectonic plates are defined as major and minor plates depending on their size. As the process repeated over time, it created a large tectonic plate with an active subduction zone. The metaphorical birth certificate for the earth's tectonic plates might be in need of an edit. In essence, plate-tectonic theory is elegantly simple. Others say it was closer to 1 billion. At this pace, it would take a million years for the two broken pieces to be 1.7 km (1 mile) apart. There are a total of seven major tectonic plates which cover nearly 95% of the Earth's surface.

But when did this activity begin? Convection refers to specific cells within the Earth’s mantle … Tectonic plates are 62 miles thick and are made up of the continental crust and the oceanic crust. The interactions of these plates shape all modern land masses and influence the major features of planetary geology — from earthquakes and volcanoes to the emergence of continents. A New Dimension to Plate Tectonics . New research suggests plate tectonics may have been well under way on Earth more than 3.2 billion years ago, adding a new dimension to the ongoing debate …