Formation of Sedimentary Rocks and Earth's Layers

Sedimentary Rocks and Their Formation

Sedimentary rocks are created from the aggregation of particles of sediments. They form layers called "Beds".

1. Weathering:

   Disintegration and decomposition of rocks or dead animals and plants.

2. Erosion:

   Natural forces (water, wind, ice...) break rocks into fragments (sediments) and transport them.

3. Deposition:

   Sediments are layered on top of one another. The old sediments are in the lower layers and the new sediments create the upper layers.

4. Lithification or Diagenesis:

   Compaction: Sediments pile up and the space between grains reduces.

   Cementation: Liquids put the aggregates together like a natural glue or cement.

Metamorphic Rocks

1. Regional Metamorphism:

   Heat and pressure increase in large areas due to tectonic movement. Foliated.

2. Contact Metamorphism:

   Regional and circular where rocks are heated because magma intrudes. Non-foliated.

Igneous Rocks

Rocks that form from the cooling of magma (molten rocks) below the Earth's crust or lava are called igneous rocks.

1. Extrusive or Volcanic:

   When magma rises from the Earth's interior and cools above the Earth's surface. They cool fast.

2. Intrusive or Plutonic:

   When magma cools inside the Earth's interior. They cool very slowly.

Earth's Layers

• Crust:

  Solid phase.

• Mantle:

  Solid phase (plasticine).

• Core:

  • Outer Core:

    Liquid.

  • Inner Core:

    Solid made of iron, nickel, and sulfur.

Why is the Inner Core Solid?

• In the inner core, pressure is 3,000,000 times greater than at sea level.

• The pressure is so great that the metals are squeezed together, and they can't be a liquid.

Why is the Outer Core Liquid?

The outer core can be a liquid because the pressure of the Earth is lower.

Minerals

• Are natural: they are created naturally.

• Are solid.

• Are inorganic: they are not created from any living organism.

• Have a fixed composition.