Story in the Rocks By: Jana Owen, Maggie Sheehan, and Jace Johansen

Weathering Weathering is when rocks are broken down in smaller pieces by the effects of weather. These pieces of rock are called Sediment. There are two types of weathering. Chemical weathering is when there is a change in some of the minerals in the rock. Physical weathering is when rock is broken into smaller pieces but the chemical makeup of the rock is the same.

Erosion Erosion is when sediment is moved somewhere else by wind, water, or ice. The main agent of erosion is running water. This means that running water usually carries sediment to a different place then it was before. One type of erosion is sheet erosion. Sheet erosion is a type of soil erosion on sloping farmland in which rain washes away a thin layer of topsoil. Gravity and living organisms cause eroded material to slide downhill.

Vocab Vocab- – Weathering- the breaking down of Earth’s rocks, soils, and minerals. – Erosion- when sediments are moved to other places by wind, water, or ice. – Deposition- when sediment is deposited somewhere. – Sediment- Broken parts of rock and other materials that are broken apart by weathering. – Gravity- The force of attraction pulling everything on Earth down/ Earth’s pull on everything

Examples The Grand Canyon- Most scientist believe that weathering and erosion made the Grand Canyon. Scientist say that the Colorado River weathered away at the rock and formed the Grand Canyon.

The Rock Cycle The Rock Cycle is the formation, breakdown, and reformation of rocks as a result of sedimentary, igneous, and metamorphic processes. There are three main ways rocks are formed. Metamorphic Rocks are formed by magma inside the Earth being compressed and heated. Igneous Rocks are formed by lava inside the Earth and on Earth’s surface being cooled. Sedimentary Rocks are formed by weathering and erosion. Rock is broken apart then transported somewhere else and deposited there. Then the sediments are cemented together.

Types of Rocks Igneous Rocks- Igneous rocks are formed by metamorphic rocks melting to form magma. Then that magma cools to form the igneous rocks. They can be formed on Earth’s surface or below Earth’s surface. Sedimentary Rocks- Sedimentary rock are formed from weathering and erosion happening on igneous rock to form sediment. Then compaction and cementation occurs on that sediment. This forms sedimentary rocks. They are usually formed underground and near water. Also sedimentary rock usually form in layers. Metamorphic Rocks- Metamorphic rocks are formed from both of the other two rock types. Both the igneous and the sedimentary rock undergo extreme heat and pressure. They are formed underground and near a volcano.

Fossils Fossils are imprints of shells, leaves, and animal’s skeletons pressed into a rock. Most fossils form in sedimentary rocks. Most fossils form from the shell, leave, or animal’s skeleton’s stuck in sedimentary rocks when they are being formed.

Law of Superposition The Law of Superposition is a law stating the newest sediments or rocks are at the top of the chain and the old rocks or sediments are at the bottom. Example- If fossilized shark teeth were found on top of a hill, we could conclude that that area used to be covered by an ocean and sedimentary rock.

Geologic Time Scale The geologic time scale is a system of measurement used to describe the timing and relationships between events that have occurred during the Earth’s history.

Vocab – Rock Cycle- Is the process in which rocks transform into another type of rock over time. – Igneous Rock- A type of rock that is formed from the cooling of magma above or below Earth’s surface. – Sedimentary Rocks- A type of rock that is formed from bits of sediment weathered and naturally cemented together. – Metamorphic Rocks- A type of rock that is formed from intense heat and pressure on igneous or sedimentary rocks. – Fossil-When an organism has been buried and compressed into a rock during its formation. – Law of Superposition- A law stating that the newest sediments or rocks are on top of the chain and the older are on the bottom. – Geologic Time Scale- A system of measurement that is used to describe the timing and relationships between events that have occurred during the Earth’s history.