Plate tectonics is the theory that Earth’s outer shell is divided into large slabs of solid rock , called “plates,” that glide over Earth’s mantle, the rocky inner layer above Earth’s core. ... It lubricates the undersides of Earth’s tectonic plates, allowing the lithosphere to move around.
What is a tectonic plate simple definition?
A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere . Plate size can vary greatly, from a few hundred to thousands of kilometers across; the Pacific and Antarctic Plates are among the largest.
What are plate tectonics kid definition?
Tectonic plates are broken pieces made of the Earth’s crust or lithosphere . Another name for them is crustal plates. Continental crust is less dense, and oceanic crust is denser. These rigid plates can move in different directions, shifting constantly.
What is the key word of plate tectonics?
noun Geology. a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates.
What is the importance of studying tectonic plates?
Plate tectonics explains why and where earthquakes occur . This makes it possible to make predictions about earthquakes. Plate tectonics explains why and where mountains are formed. The oceans according to plate tectonics are formed by divergent boundaries.
Why are there tectonic plates?
The plates can be thought of like pieces of a cracked shell that rest on the hot, molten rock of Earth’s mantle and fit snugly against one another. The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other.
What are the two types of plates?
There are two types of plates, oceanic and continental .
What causes the plates to move kids?
These plates move because of heat from Earth’s core . Earth’s radioactive core generates an immense amount of heat that keeps our planet from completely cooling over. Less dense molten rock travels from the core to the surface, where it then cools and returns—a process called convection.
How many plate tectonics are there?
There are seven major plates: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American. The Hawaiian Islands were created by the Pacific Plate, which is the world’s largest plate at 39,768,522 square miles.
What is the best definition of plate tectonics?
1 : a theory in geology: the lithosphere of the earth is divided into a small number of plates which float on and travel independently over the mantle and much of the earth’s seismic activity occurs at the boundaries of these plates .
What are the 4 types of plate tectonics?
There are four types of boundaries between tectonic plates that are defined by the movement of the plates: divergent and convergent boundaries, transform fault boundaries , and plate boundary zones.
How do plate tectonics affect humans?
Plate tectonics affects humans in several important ways. What would Earth be like without plate tectonics? We’d have many fewer earthquakes and much less volcanism, fewer mountains, and probably no deep-sea trenches. ... In other words, the Earth would be a much different place.
What happens when tectonic plates move?
When the plates move they collide or spread apart allowing the very hot molten material called lava to escape from the mantle . When collisions occur they produce mountains, deep underwater valleys called trenches, and volcanoes. ... The Earth is producing “new” crust where two plates are diverging or spreading apart.
How fast do tectonic plates move?
They can move at rates of up to four inches (10 centimeters) per year , but most move much slower than that. Different parts of a plate move at different speeds. The plates move in different directions, colliding, moving away from, and sliding past one another. Most plates are made of both oceanic and continental crust.
What is the oldest tectonic plate?
Summary: Identification of the oldest preserved pieces of Earth’s crust in southern Greenland has provided evidence of active plate tectonics as early as 3.8 billion years ago, according to a report by an international team of geoscientists in Science magazine.
