ENV 151 Study Guide - Quiz Guide: Igneous Differentiation, Vesicular Texture, Rhyolite
Document Summary
Intrusive igneous rocks cool below the surface of the earth. Granite has a phaneritic, or coarse-grained texture whereas rhyolite is aphanitic, or fine-grained. They are compositionally similar, being granitic or felsic rocks. Magmatic differentiation occurs as magma cools and crystals of minerals with higher melting temperatures crystallize out of the magma, changing the magmatic composition. Sedimentary rocks contain almost all of the fossil record. Sedimentary rocks make up about 75% of continental rock outcrops and contain clues to the history of the earth"s surface. Quartz and clay minerals, especially from feldspars, are most abundant. These rocks predominate in conglomerate, breccia, sandstone, arkose, siltstone, and shale: distinguish between conglomerate and breccia. Both are made of large sized sedimentary grains. Give an example of a rock that belongs to each category. Evaporites form when minerals are dissolved in solution, and the water of that solution evaporates away.