The Rock Cycle

The Rock Cycle | infohow.org

The Rock Cycle | infohow.org

GEOLOGY is the study of the Earth and what it’s made of, including its natural history. This history is recorded in rocks and it describes how the earth is always changing and reshapes over time. The Rock Cycle highlights how three main types of rocks, SEDIMENTARY, METAMORPHIC, and IGNEOUS came to be and where they came from. Each type of rock changes conditions over time. Rocks are destroyed, melted down, and reform through various ways:

  • weathering and erosion
  • sedimentation and deposition
  • cooling and crystallizing melting
  • heat and pressure
  • lithification (compacting and cementing)
basalt | igneous

basalt | igneous

IGNEOUS

Igneous rocks are formed of magma, the molten form of the earth’s mantle layer. Igneous rocks can form above ground as lava spewing from volcanoes. But igneous rocks can also form below the surface. Pockets of magma get stuck in layers of the earth.

As they get closer and closer to the surface, the magma slowly cools. Granite is an igneous rock that formed from a slow-cooling pocket of magma (rocksandminerals4u.com, 2013).

Like basalt, igneous rocks form from lava and magma.

conglomerate.sedimentary

conglomerate | sedimentary

SEDIMENTARY

Sedimentary rocks form from small weathered particles of other rocks or the weathered shells of sea animals. Wind and rain beating on the faces of exposed rock tend to wear off particles that are blown or washed to a new location.

When sea creatures die, the shells settle on the bottom of the ocean. As the sediments pile up, they press together to form Sedimentary rock (rocksandminerals4u.com, 2013).

Like conglomerate, sedimentary rocks form from sediment and chemical precipitation from seawater.

serpentinite.metamorphic

serpentinite | metamorphic

METAMORPHIC

Metamorphic rocks form under intense heat and pressure. Metamorphic rocks start out as igneous rocks, sedimentary rocks or other types of metamorphic rocks, but through heat or pressure, change characteristics such as sheen, tightness of grain and hardness.

Rocks continually change form. What started out as sedimentary rock may change to metamorphic and, with time and weathering, change back to sedimentary (rocksandminerals4u.com, 2013).

Like serpentinite,metamorphic rocks form from other rocks that recrystallize under higher pressures and temperatures.

(B.Ed students | YouTube.com)

LEARN MORE: INTERACTIVES – ROCK CYCLE

LEARN MORE: THE LEARNING ZONE – ROCKS

DOWNLOAD PDF: THE ROCK CYCLE (coming soon)

  1. Rocks are classified into one of three groups, depending on how they form. What are three rock classifications?
  2. What geological process is needed in order for an igneous rock to form?
  3. Which physical characteristic is most helpful in classifying sedimentary rocks?
  4. Which physical characteristic is least helpful in classifying sedimentary rocks?
  5. Which type of rock would you expect to be common on the floor of a large, deep lake? Why?
  6. Would you expect to find metamorphic rock deep in Earth’s crust? Why or why not?


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6 replies

  1. In the rock cycle it has metamorphic rock, igneous rock,sedimentary rock.You can find rocks anyware i had a book order i order the deadly rock i am going to get it soon.lol

  2. I think learning about different forms of rocks is an educational adventure!

  3. Igneous rocks are formed when magma melts. 🙂

  4. 1.Igneous, Sedementary, and Metamorphic. 2. As the magma cools a Igneous rock forms. 3. Sedimentary rocks look like it has holes and layers. 4. Sedimentary rocks also have a little tiny rocks in it as well. 5. I think a Sedimentary rock would be on the of a lake. 6. No you would not expect to find Metamorphic deep in the earth’s crust because only Igneous form down there.

    • I have a friend that did a project with igneous, sedimentary, and metamorphic. and he had vinegar and some toxic liquid he put those three rocks in the toxic one and three in the vinegar. and he waited 2 weeks to see what happend. What do you think happend? What’s your hypothesis?

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