THE ROCK CYCLE MELTING COOLING MELTED ROCK WEATHERING, AND DEPOSITION EROSION, METAMORPHIC ROCK THE ROCK CYCLE HEAT AND PRESSURE IGNEOUS ROCK SEDIMENTARY ROCK WEATHERING, EROSION, AND DEPOSITION COMPACTION AND CEMENTATION SEDIMENT

The Rock Cycle The Earth is constantly changing. Even the very rocks around you may have changed many times throughout their history! The Rock Cycle explains the evolution of these igneous, sedimentary, and metamorphic rocks that make up the Earth’s crust. Many processes, such as volcanic activity, movement of the crust, and erosion and deposition of rocks on the surface, create different environments where various types of minerals and rocks form. Let’s take a ride on the Rock Cycle! Back to the beginning

Melting…

MELTED ROCK Generally appears at plate boundaries when crustal plates are colliding or spreading apart. Magma forms beneath the surface. Lava is found on the surface. Lava Magma Go back to the Rock Cycle Cool this melted rock!

Cooling…

IGNEOUS ROCKS Form as melted rock cools. Can be extrusive or intrusive. Examples include granite, basalt, and obsidian. Choose your own Adventure: Add some heat and pressure! Weather and erode this rock! Go back to the Rock Cycle

WEATHERING AND EROSION Did you know that the sand on the beach used to be part of a rock? Once a rock is made, it doesn’t stay that way! If it is on the surface, the rock is broken down into sediments by weathering processes, then moved to a new location by erosional forces. Weathering is the process of decomposition or disintegration of rocks in place. Erosion is the movement of weathered materials by water, wind, ice, or gravity. Go back to the Rock Cycle Deposit sediment

SEDIMENTS Sediments are mineral or organic particles that are deposited by the action of wind, water, ice, or gravity. Boulders, gravel, sand, and mud are all types of sediments. Compact and cement these sediments! Go back to the Rock Cycle

SEDIMENTARY ROCKS Examples of sedimentary rocks As the sediments settle, they compact. If the sediments are small enough, they can form rocks. If the sediments are large, natural cements fill in the empty spaces and “glue” the sediments together. Choose your own Adventure: Weather and erode this rock! Add heat and pressure to this rock! Examples of sedimentary rocks include sandstone, shale, and limestone. Go back to the Rock Cycle.

METAMORPHIC ROCKS These rocks have gone through a lot! Metamorphic rocks form from pre- existing rocks that have changed due to high temperatures, pressures, or chemical changes. Choose your own Adventure: Melt this rock! Weather and erode this rock! Examples of metamorphic rocks include gneiss, slate, and marble. Go back to the Rock Cycle

GLOSSARY Cement: A substance that hardens to act as an adhesive; glue. Compact: become pressed together Erosion is the movement of weathered materials by water, wind, ice, or gravity. Extrusive: an igneous rock formation environment that occurs on the surface Intrusive: an igneous rock formation environment that occurs beneath the surface Lava: molten rock on the Earth’s surface Magma: molten rock beneath the Earth’s surface Weathering is the process of decomposition or disintegration of rocks in place. Take me back to the Rock Cycle!

Granite Intrusive igneous rock. Cools slowly and has large crystals. Generally found on the continents. Go back to Igneous Rocks

Basalt Extrusive igneous rock Cools quickly and has small crystals. Oceanic crust is made up of basalt. Go back to Igneous Rocks

Obsidian Often called “volcanic glass” Extrusive igneous rock that cools extremely quickly. Does not have crystals. Go back to Igneous Rocks

Sandstone A sedimentary rock consisting of quartz sand cemented together by other minerals. May be many colors, including grey, yellow, red, and white. Is capable of holding large quantities of water. Go back to Sedimentary Rocks

Shale Formed from clay and mud particles that have been pressed into thin sheets. Extremely fine-grained material Go back to Sedimentary Rocks

Limestone Generally forms from calcite produced by marine organisms, and may contain fossils. May also form from groundwater containing dissolved calcite. Will “fizz” when in contact with hydrochloric acid (HCl). Go back to Sedimentary Rocks

Gneiss A coarse-grained rock with bands of light colored minerals that alternate with bands of dark-colored minerals. Similar in composition to granite (quartz, feldspar, mica) Go back to Metamorphic Rocks

Slate Fine-grained rock composed of metamorphosed clay or volcanic ash. Generally forms when shale undergoes metamorphism. Has distinctive layers. Go back to Metamorphic Rocks

Marble building material Does not have layers or bands Metamorphosed limestone Often used in sculpture and as a building material Does not have layers or bands Go back to Metamorphic Rocks