The Rock Cycle
Sedimentary, metamorphic, igneous rocks
Rocks that are used for everyday life
The rock cycle never ends
Basalt may be classified on a chemical and petrographic basis into two main groups, the tholeiitic and the alkali basalts.
Basalt forms when lava reaches the earths surface at a volcano or mid ocean ridge. The lava is between 1100 to 1250 C when it gets to the surface. It cools quickly within a few days or couple weeks forming solid rocks.
Basalt is usually found on the seafloor.
Basalt is used for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast.