Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Section 4-2 • How are igneous rocks formed? • What is the difference between magma and lava? • What is the difference between intrusive and extrusive rocks? • Describe the 3 types that igneous rocks can be classified into. • Igneous rocks are formed when molten material from a volcano or from deep inside the Earth cools and hardens. • Magma is molten rock that is beneath the Earth’s surface and lava is magma that has reached the Earth’s surface and flows from a volcano. • Intrusive rocks are igneous rocks that form below the Earth’s surface. • They cool slowly and have large mineral grains. • Extrusive rocks are igneous rocks that form when lava cools on or near the Earth’s surface. • They cool quickly and have a fine-grained texture. • Sometimes the lava cools so quickly that air bubbles get trapped in the lava leaving behind holes in the rock. Types of Igneous Rocks • Basaltic – are dense, heavy, and dark-colored; are rich in iron and magnesium; are produced by Hawaiian volcanoes • Granitic – are light-colored and less dense; contains a lot of silicon and oxygen; can cause violent volcanic eruptions • Andesitic - have mineral compositions between basaltic and granitic Basaltic Granitic Andesitic Igneous rocks are the most abundant type of rock on Earth.