Chapter 4: Igneous Rocks I Product of Earth's Internal Fire
Chapter 4: Igneous Rocks: Product of Earth’s Internal Fire
ntroduction: What Is an Igneous Rock? gneous rocks vary greatly. Some contain large mineral grains. Others contain grains so small they can barely be seen under a high power microscope. gneous rocks also vary greatly in color. All igneous rocks are formed through the cooling and solidification of magma
Introduction: What Is an Igneous Rock? ◼ Igneous rocks vary greatly. ◼ Some contain large mineral grains. ◼ Others contain grains so small they can barely be seen under a high power microscope. ◼ Igneous rocks also vary greatly in color. ◼ All igneous rocks are formed through the cooling and solidification of magma
Intrusive Versus Extrusive Igneous rocks Intrusive igneous rocks form when magma cools within existing rocks in Earth's crust a Extrusive igneous rocks form when magma cools on Earths surface, where they have been“ extruded
Intrusive Versus Extrusive Igneous Rocks ◼ Intrusive igneous rocks form when magma cools within existing rocks in Earth’s crust. ◼ Extrusive igneous rocks form when magma cools on Earth’s surface, where they have been “extruded
Texture In Igneous Rocks The two most obvious textural features of an igneous rock are the size of its mineral grains and how the mineral grains are packed together. Sizes of mineral grains Intrusive rocks are coarse-grained Magma that solidifies in the crust cools slowly and has sufficient time to form large mineral grains
Texture In Igneous Rocks The two most obvious textural features of an igneous rock are the size of its mineral grains and how the mineral grains are packed together. Sizes of mineral grains: ◼ Intrusive rocks are coarse-grained. ◼ Magma that solidifies in the crust cools slowly and has sufficient time to form large mineral grains
Texture In Igneous Rocks Extrusive rocks are fine-grained a Magma that solidifies on the surface usually cools rapidly, allowing insufficient time for large crystals to grow. a Coarse-grained igneous rock is called a phanerite显晶岩( from the greek word meaning visible)
◼ Extrusive rocks are fine-grained ◼ Magma that solidifies on the surface usually cools rapidly, allowing insufficient time for large crystals to grow. ◼ Coarse-grained igneous rock is called a phanerite 显晶岩(from the Greek word meaning visible). Texture In Igneous Rocks