Essential Question: What is the composition of rocks and how are they formed? Standards: S6E5b. Investigate the contribution of minerals to rock composition. S6E5c. Classify rocks by their process of formation. S6E5d. Describe processes that change rocks and the surface of the earth.

Composition of Rocks Minerals Rock fragments (smaller pieces of other rocks) Organic matter (remains of organisms and their wastes) Other natural materials

There are three types of rocks: Igneous, Metamorphic, and Sedimentary Rocks are classified based on how they formed and their mineral composition. There are three types of rocks: Igneous, Metamorphic, and Sedimentary

Igneous Rock

Igneous Rock forms from hot molten lava or magma that cools and crystallizes

Igneous Rock can form below the surface Igneous Rock can form below the surface. These igneous rocks cool slowly so the mineral grains are coarse-grained and easy to see

Igneous Rock can form on the surface Igneous Rock can form on the surface. These igneous rocks cool quickly so the mineral grains are fine grained.

Some Igneous Rock cools so quickly that few or no mineral grains form. Other cools so quickly that gases become trapped and later leave holes once the gases escape.

Igneous Rock

Examples of Igneous Rock Granite Pumice Basalt Obsidian

Metamorphic Rock

Metamorphic Rock forms when a rock is changed by heat and or pressure

Increasing Heat and Temperature Basalt Greenstone Schist Increasing Heat and Temperature

Examples of Metamorphic Rock Gneiss Schist Slate Marble

Sedimentary Rock

Sedimentary Rock forms by the ongoing buildup (deposition) of rocks and other sediments that become compacted (packed) and cemented (joined).

Examples of Sedimentary Rock Sandstone Shale Limestone

Most fossils are located in sedimentary rock Most fossils are located in sedimentary rock. Based on what you have learned so far about the three types of rock, turn to an elbow partner and discuss why.