The Rock Cycle
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What are rocks?
There are different types of rocks, depending on their genesis.
The Rock Cycle
Geosphere is made of rocks. Rocks are solid aggregates of one or more minerals.
Minerals, remember?
- SOLID
- NATURAL OCCURRING
- CHEMICAL FORMULA
- INORGANIC
- CRYSTAL STRUCTURE
IGNEOUS ROCKS
They are formed through the cooling and solidification of magma.
So... magma is melted rock. Rocks melt because of high pressures or temperatures, in the crust or the upper mantle.
We divide igneous rocks in plutonic and volcanic rocks.
Fossils are found in sedimentary rocks. They are preserved remains or traces of organisms from the past.
Marble
Plutonic or intrusive rocks are formed within the Earth's crust.
They have big crystals, because they cool slowly.
Volcanic or extrusive rocks are formed on the surface (from lava), so they cool quickly. They don't have big crystals.
Diorite
Obsidian
SEDIMENTARY ROCKS
Sedimentary rocks are formed at the earth's surface by the accumulation of fragments of earlier rocks, and organic particles too!!
Due to high pressure, cementation of those fragmens occurs.
METAMORPHIC ROCKS
Metamorphism means "change in form". Any type of rock suffers a deep change in its physical and chemical properties, due to changes in pressure and temperature conditions.
Do they keep their properties forever? Nope.
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