The Rock Cycle

Why is it important for scientists, especially engineers, to know about rocks? Engineers must know about rocks, how they are formed, and how strong they are so that they can design safe buildings, tunnels and bridges for us. Engineers also use their knowledge of rocks to help determine and prevent natural disasters to humans from rock falls, landslides and earthquakes.

How are rocks made? Can they change over time?

The Rock Cycle Rocks- a naturally occurring solid mixture of one or more minerals and organic matter The Rock Cycle- the series of processes in which a rock forms, changes from one type to another, is destroyed and forms again by geological processes.

Definition Picture Example  

Processes that shape the Earth Weathering- the process by which water, wind, ice, and heat break down rock into fragments(destructive process) These rock and mineral fragments are the sediment that make up sedimentary rocks.

Processes that shape the Earth EroSion- the process by which Sediment is removed from its source. Water, wind, ice and gravity can erode land, move sediments, and cause them to collect.

Processes that shape the Earth Deposition- the process in which sediment moved by erosion is dropped elsewhere, where it is pressed and cemented together to form sedimentary rocks (constructive process)

Compaction- the process by which sediment is compressed and packed/cemented together to form sedimentary rock

Metamorphism- intense heat and pressure heat and squeeze sedimentary rock into metamorphic rock; means change

Melting- rocks partially or completely melt due to high heat and turn into magma Cooling – magma is less dense and will rise; when it cools, it turns into igneous rock

Solidification- uplift and erosion expose igneous rock at the Earth’s surface. Weathering and wearing away take place; grains of sediment are then deposited elsewhere Uplift- movement within the Earth that causes rocks inside the Earth to be moved to the Earth’s surface (earthquakes, volcanoes, plates colliding, faults)

Round and Round it Goes Each type of rock can be changed into the three types of rocks. Igneous to metamorphic, sedimentary or back to igneous. Sedimentary to metamorphic, to igneous, or back to sedimentary Metamorphic to igneous to sedimentary back to magma