Question

what do u mean by the words basalt,granite,igneous rocks,pumice

Answer 1

 



Excluding the rocks between my ears, I'd have to say that basalt and granite have the honor of being the most important rocks in the crust.

Basalt and granite actually have quite a bit in common. Both are igneous rocks, which means that they cooled from a magma (the earth gets very hot just below the surface, and there is lots of liquid rock available). Both are made up of minerals from the silicate group, so both have large amounts of silicon and oxygen. Both will hurt if you drop a big piece on your toe. But there are several important differences, too. These differences help define and explain how the earth works.

Granite is great stuff! Not only is it my personal favorite, it is without a doubt the most common rock type on the continental land masses. Yosemite Valley in the Sierra Nevada and Mt. Rushmore are two notable examples of granitic rocks. But granitic "basement rock" can be found just about everywhere east of the Rockies if you're willing to dig through the dirt and sedimentary rocks at the surface. Granite is intrusive, which means that the magma was trapped deep in the crust, and probably took a very long time to cool down enough to crystallize into solid rock. This allows the minerals which form plenty of time to grow, and results in a coarse-textured rock in which individual mineral grains are easily visible ridge.