What Are The Theories Of Plate Tectonics?

What are the 3 theories of plate tectonics?

Plates interact at three types of plate boundaries: divergent, convergent and transform.

Most of the Earth’s geologic activity takes place at plate boundaries.

At a divergent boundary, volcanic activity produces a mid ocean ridge and small earthquakes..

What is the theory of plate tectonics Class 9?

Plate tectonics is the theory that Earth’s outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is called the lithosphere.

How fast do tectonic plates move?

They move at a rate of one to two inches (three to five centimeters) per year.

How do the Earth’s plates move?

Plates at our planet’s surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when warm material rises, cools, and eventually sink down. As the cooled material sinks down, it is warmed and rises again.

What are the three types of boundaries?

There are three main types of plate boundaries:Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. … Divergent boundaries – where two plates are moving apart. … Transform boundaries – where plates slide passed each other.

Who postulated the concept of plate tectonics?

scientist Alfred WegenerDeveloped from the 1950s through the 1970s, plate tectonics is the modern version of continental drift, a theory first proposed by scientist Alfred Wegener in 1912. Wegener didn’t have an explanation for how continents could move around the planet, but researchers do now.

What are the different theories of plate tectonics?

Three-dimensional diagram showing crustal generation and destruction according to the theory of plate tectonics; included are the three kinds of plate boundaries—divergent, convergent (or collision), and strike-slip (or transform).

What are the theories of continental drift and plate tectonics?

The Theory of Plate Tectonics builds on Wegener’s Theory of Continental Drift. In the Theory of Plate Tectonics, it is tectonic plates, rather than continents, which are moving. Tectonic plates are pieces of the lithosphere and crust, which float on the asthenosphere.

What are 2 theories about plate tectonics?

The theory of plate tectonics states that the Earth’s solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle. Oceanic and continental plates come together, spread apart, and interact at boundaries all over the planet.

How many plates do you see?

There are seven major tectonic plates that very slowly move around on the surface of our planet along with a number of minor plates. Let’s take a look at the seven major plates of the lithosphere.

What are the 4 major sources of evidence for the theory of plate tectonics?

Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Fossils tell us when and where plants and animals once existed. Some life “rode” on diverging plates, became isolated, and evolved into new species.

What are the 2 theories behind why tectonic plates move?

Why do plates move? One explanation for plate movements is slab pull. Plates are extremely heavy so gravity acts upon them, pulling them apart. Alternatively, as shown in the diagram, convection currents under the Earth’s crust transfer heat, which rises through the surface and cools back down in a circular motion.

How did Pangea split?

During the Triassic Period, the immense Pangea landmass began breaking apart as a result of continental rifting. A rift zone running the width of the supercontinent began to open up an ocean that would eventually separate the landmass into two enormous continents.

Which part of Earth do we live on?

crustThe crust is the outermost layer of Earth, and it is the one we live on. You can think of the crust as a thin shell that covers the earth.

How many plate tectonics are there?

sevenhow many tectonic plates are there? There are major, minor and micro tectonic plates. There are seven major plates: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.

What causes plates to move?

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 5 pieces of evidence that support continental drift?

In the early part of the 20th century, scientists began to put together evidence that the continents could move around on Earth’s surface. The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones.

What is the difference between plate tectonics and tectonic plates?

Plate tectonics is a scientific theory that describes the large-scale motion of Earth’s lithosphere. … The lateral relative movement of the plates typically varies from zero to 100 mm annually. Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust.