Rock Cycle Notes

Rock Cycle

Weathering and Erosion

  • Weathering and erosion break down rocks into smaller particles.

  • Different particle sizes include gravel, sand, silt, and clay.

  • Transportation and sedimentation are important processes.

  • Fast flow transports sand.

  • Medium flow transports silt.

  • Slow flow transports clay.

Sediments and Sedimentation

  • Sediments are particles of rock fragments.

  • Sedimentation is the process where sediments are deposited.

  • Over time, sediments compact into layers through lithification, which transforms them into sedimentary rocks.

  • Examples of sedimentary rocks: limestone, sandstone, and claystone.

Weathering and Erosion Examples

  • The brown color of water from the Ethiopian Plateau is due to weathering and erosion.

  • Agricultural soil in Egypt was formed over millions of years by the same processes.

  • Rainfall on the Ethiopian Plateau causes weathering and erosion; rock fragments are transported away.

Properties of Sedimentary Rocks

  • Sedimentary rocks are porous due to spaces between sediment particles.

  • Contain fossils.

Importance and Harms of Erosion

  • Erosion is important for the formation of river deltas.

  • Erosion can harm coastlines (coastal erosion) due to sea waves.

Metamorphic Rocks

  • Formation occurs under heat and pressure beneath the Earth's surface.

  • Particles come closer together.

  • Spaces between particles decrease.

  • Hardness increases.

Examples of Metamorphism

  • Limestone transforms into marble.

  • Sandstone transforms into quartzite.

Igneous Rocks

  • Formed from magma.

Formation of Igneous Rocks

  • Magma cools, forming plutonic igneous rocks.

  • Lava cools, forming surface igneous rocks.

Types of Igneous Rocks

  • Plutonic rocks:

    • Formed from magma.

    • Cool slowly, resulting in large crystals.

  • Surface volcanic rocks:

    • Formed from lava.

    • Cool quickly, resulting in small crystals.

  • Examples: Gabbro, Granite, Pumice, Basalt.

Examples of Rock Uses

  • Marble used in the Taj Mahal in India.

  • Limestone used in the Pyramids of Giza in Egypt.

Rock Cycle

  • Magma: Melting.

  • Igneous rocks: Cooling, and weathering and erosion.

  • Sediments: Compaction and lithification, and weathering and erosion.

  • Sedimentary rocks: Heat and pressure, and weathering and erosion.

  • Metamorphic rocks: Heat and pressure.

Formation of Fossil Fuels

  • Formed millions of years ago from physical and chemical changes of organic substances in the Earth's interior.

  • Plants (especially large ones) are the organic origin of coal.

  • Marine microorganisms are the organic origin of petroleum oil and natural gas.

  • Methane gas is the major component of natural gas (forms more than 90%).