Please enable JavaScript.
Coggle requires JavaScript to display documents.
Module 8.2 (Magma and Lava (Magma is very hot molten (melted) rock. Magma…
Module 8.2
Magma and Lava
Magma is very hot molten (melted) rock. Magma is less dense than the surrounding rock, so it rises up through any fault, crack or weak spot in the crust above
Igneous rock is formed when magma or lava cools and crystallises (forms crystals). Some igneous rocks form at the surface of the Earth.
Some igneous rocks form when magma is trapped in cracks or between layers of rock below the surface. Other igneous rocks form deep in the crust.
-
-
-
Intrusive Igneous rock
Intrusive igneous rocks contain larger crystals, which can usually be seen without a microscope. These crystals are the result of magma cooling slowly.
-
Most igneous rocks are very hard and strong. These characteristics make them good for buildings and other stone structures that need to last a long time
Extrusive igneous rocks
An example is pumice, which does not absorb water and has a low density. These properties allow it to float. Scoria is another type of rock that erupts out of volcanoes.
The holes or spaces in some igneous rocks are caused by gas bubbles, which were trapped when the lava cooled very quickly. This gives the rock a rough, bubbly texture
-