Active World

Tectonics

7beac300-7f57-496e-9b2b-b323146b6f67 (image/png)

Structure of the Earth

The inner core is 5,500°C - extremely hot. It is a very dense solid made from iron and nickel. The outer core is 2,000 km thick and is a liquid. The mantle is semi-molten and about 3,000 km thick. The crust is the outer layer of the earth. It is a thin layer between 0-60 km thick. The crust is the solid rock layer upon which we live.

6d67e17f-360d-4a7a-822f-443ef77f95b3.gif (image/gif)

Constructive Plate Margins

A constructive plate boundary occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.An example of a constructive plate boundary is the mid-Atlantic Ridge.

296c7080-372c-4967-8556-48ba6852e4ac (image/png)

Destructive Plate Margin

A destructive plate boundary occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface.An example of a destructive plate boundary is where the Nazca plate is forced under the South American Plate.

35d828c2-a492-466b-b470-f312940616c2 (image/png)

Collision Plate Margin

Collision zones form when two continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains.

e1fbb427-03ee-4d3b-b9fb-330c0a6b1450 (image/png)

Conservative Plate Margin