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ESO 3 B & G · 7 · Rocks

What to Learn

  • Concept of rock and how it relates to the concept of mineral.
  • Basic properties of the rocks: structure, mineral composition and age.
  • Sedimentary rocks: formation process, occurrence, strata, major types and main examples.
  • The formation of coal and petroleum.
  • Igneous rocks: formation process and its determining factors, occurrence, major types and main examples.
  • Metamorphic rocks: formation process and its determining factors, occurrence, major types and main examples.
  • The rock cycle.
  • Rocks as resources for human societies.
  • Major lithological units in Spain.

Key Information

Rock Grains

Sedimentary rocks can be made up of clasts or detritus (rock grains) weathered from other rocks by river waters, wind, coastal sea waters, glaciers, living beings, etc. This kind of sedimentary rocks are called detrital rocks.

They're classified upon the grains that they are made up of. First up, grains may be all the same size, uniform, as in a sandstone, or different sizes, as in a conglomerate. Secondly, grains may be bigger or smaller. The following table shows roughly how rock grains are classified upon their size:

Diameter
Clay< 0.004 mm
Silt< 0.06 mm
Sand< 2 mm
Gravel< 6 cm
Cobble< 25 cm
Boulders> 25 cm

Movies, Animations and Audios

The Rock Cycle
Rocks

Rocks

An overview of the rock transformation processes on our planet.

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