Presentation on theme: "What is the The rock cycle is the series of processes in which a rock forms, changes from one type to another, is destroyed, and forms again by geological."— Presentation transcript:
Igneous rocks are rocks that form when molten material cools and solidifies.
General characteristics of magma: Rocks formed from lava are EXTRUSIVE Rocks formed from magma are INTRUSIVE
General characteristics of magma: Texture: Texture refers to the size and shape of the crystals that make up the rock. Fine Grained Texture: Fast cooling rock. Mineral crystals do not have much time to form. Coarse Grained Texture: Slow cooling rock. Mineral crystals have time to form.
Composition: Light-colored igneous rocks: High in silicon Lower density. Ex. Granite, Rhyolite Dark-colored igneous rocks: High in calcium, iron, and magnesium. LOW in silicon Higher density Ex. Gabbro, Basalt
Intrusive Igneous Rock: Forms from magmaForms from magma Forms below the surfaceForms below the surface Slow coolingSlow cooling Usually coarse-grained (large crystals)Usually coarse-grained (large crystals)
Extrusive Igneous Rock: Forms from lavaForms from lava Forms above the surfaceForms above the surface Fast coolingFast cooling Usually fine-grained (small crystals)Usually fine-grained (small crystals)
Slow cooling, large crystals Quick cooling, small crystals
Most of the ocean floor is composed of basalt. Basalt is extrusive and fine-grained
Tectonic forces like converging plates can cause plates or sometimes regions to uplift. Forces of erosion such as rain, wind, and glaciers can wear away layers of softer sedimentary rock exposing the underlying igneous rock