Notes-The Rock Cycle

Rocks are Made of Minerals Rock- a naturally formed solid usually made up of one or more minerals.

Rocks are Made of Minerals Rocks are NOT minerals. The amount of the various minerals in a particular kind of rock can change.

Rocks are Made of Minerals The minerals in a rock are sometimes jumbled together with no crystal structure.

Rocks are Made of Minerals Some rocks are made of only one mineral. Example: Limestone can be made of pure Calcite.

Rocks are Made of Minerals Some rocks are made of no minerals at all. Example: Obsidian

The Rock Cycle Rocks change over thousands or millions of years. Rock cycle-the set of natural processes that form, change, break down, and re-form rocks.

Rocks do not go through the rock cycle in any particular order. The rock cycle has no beginning or ending-it goes on and on and on.

The 3 types of rock are classified by how they form.

Igneous rock forms when molten rock cools and becomes solid.

Igneous rock can form inside Earth or on Earth’s surface.

Sedimentary rock is formed when sediment gets pressed together. Sediment: tiny pieces of older rocks, plants, and other loose material

Sediment forms when rocks are weathered. Sedimentary Sediment forms when rocks are weathered.

Sedimentary The sediment is carried by water or wind and settles into layers that are pressed down over time into rock.

Metamorphic Metamorphic rock forms when heat or pressure causes older rocks to change into new rocks.

Metamorphic The changes in heat and pressure cause the structure of the rock to change and new minerals to form.

Rocks in the Crust Igneous, sedimentary, and metamorphic rocks are all found in Earth’s crust.

Sedimentary rock makes up only 5% of the crust. Rocks in the Crust Most of Earth’s crust (95%) consists of igneous rock and metamorphic rock. Sedimentary rock makes up only 5% of the crust.

Rocks in the Crust However, sedimentary rocks are the most common type found on the surface. Why?

Rocks in the Crust Because they are formed by weathering and erosion, which occur on the surface.

The 3 groups of rock are sedimentary, metamorphic, and Limestone Review The 3 groups of rock are sedimentary, metamorphic, and Limestone Granite Igneous Coal

2. The rock cycle shows how rocks continually Increase in size Review 2. The rock cycle shows how rocks continually Increase in size Increase in number Become more complex Change over time

3. What kind of rock forms when molten rock cools? Metamorphic Review 3. What kind of rock forms when molten rock cools? Metamorphic Sedimentary Igneous Extrusive

Review 4. An existing rock can change into another type of rock when it is subjected to great Pressure Winds Flooding Foliation