Plate Tectonics

By: Lizzy Heddin Period: 1

Layers of the Earth

Crust- The crust is important because it contains fossil fuels and we live on it. If the earth didn't have the crust layer, it wouldn't have plants to grow, which means no oxygen for us to breath.

Mantle- The mantle is 84% of the earth's volume and 64% of the earth's mass. The mantle adds new crust when plates separate or volcanoes erupt.

Core- the magnetic field is important to us because without it we would fry up from the Sun and cosmic rays.

Continental Drift

Movement of the Earth's continents relative to each other. Continents drift towards each other at least 2 cementers each year because of the magma moving underneath the crust. This theory was found in the 1900's by Alfred Wegener. Same animals are being discovered in Madagascar and India. The continents seem like they could fit perfectly together, like a puzzle. (picture of Alfred Wegener below)
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Sea-Floor Spreading

2 oceanic plates spread apart from each other and the magma from the mantle rises up and creates new crust. Over time the oceanic plates slowly move into the continental plate, which slowly move the continents.

Convection helps with Plate Movement

When oceanic plates collides with a continental plate, the oceanic plate goes under the continental plate because the oceanic plate is less dense than the continental plate. Over time what went under the continental plate comes back up and forms new crust and over a longer period of time the continent move slowly.

Theory of Plate Tectonics

The outer layer, the crust, is divided into multiple plates that slowly move around across the earths surface.

The Ring of Fire

A huge area comprising of many volcanoes around the Pacific Ocean, amounts for almost 80% of the worlds seismic activity, earthquakes. Contains a large majority of volcanoes and volcanic activity.

Geographical Features and Natural Disasters causes by Plate Boundires

Earthquakes, tsunamis, trenches, volcanoes, mountains, mid-ocean ridges, rift valleys, and sea-floor spreading