Plate Tectonics Introduction

Lets start with an introduction of Plate Tectonics:

• Plate Tectonics is the study of how it is that continents are able to move around the word's crust.

What are tectonic plates?

• There are seven large plates and several smaller ones, all moving very slowly at diferent speeds and directions.
• Some of them are under the oceans, those are called oceanic plates and some of them are under continents, they are called continental plates.
• A boundary is where two plates meet, this is the place where new crust forms and the old crust is returned to the core to be melted again.
• The proces of new crust forming takes about 100 million years.
• Tectonic plates are made of rigid lithosphere.

We should already know that the Earth is formed of 4 main layers: the inner core, the outer core, the mantle and the crust.

• The core is made mostly of iron. 
• The inner core is under such an extreme pressure that it remains solid,
•  the outer core is liquid. 
• The liquid in the outer core flow in currents that makes the magnetic field of the Earth.

What is the lithosphere?

• The lithosphere is made of the crust and the upper mantle, it flotes on top of the asthenosphere, which is also part of the upper mantle and goes down to a maximum depth of 600km.