GEOL 101 Lecture Notes - Lecture 4: Porphyritic, Phanerite, Aphanite
Document Summary
Igneous rocks are rocks that were once molten. Lava is molten rock extruded onto the earth"s surface. Magma is a word meaning molten rock contained within the earth. Magma that cools and solidifies within the earth is called intrusive igneous rock. Lava that cools and solidifies on the surface of the earth is called extrusive igneous rock. A naturally occurring solid aggregate of minerals or mineral-like substances. Texture size, shape, and arrangement of crystals or grains . The openings are from air bubbles escaping while the lava was still molten. They are called amygdules when they are filled with secondary minerals and rock is called a vesicular basalt . All melting of rock starts in the mantle with the melting of peridotite or the green mineral olivine + minor amounts of green pyroxene. In general, the earth is divided into three main parts. The crust is the outer layer of rock that forms a thin skin on earth"s surface
