Rocks

Rocks


ROCKS

Naturally-occurring mixtures of minerals, mineraloids, glass or organic materials.
They are divided into 3 groups based on how they were formed. Igneous, Sedimentary and Metamorphic.
Rocks are made up of one or more minerals.
Once a rock is formed, it does not stay the same rock forever.
Rocks are constantly changed by many processes such as weathering, erosion, melting, compaction, cementation and cooling.
Rocks can change to and from the three types.
The process through which rocks change is called The Rock Cycle.

The Rock Cycle- earth materials change back and forth among the different types of rocks.

The core, mantle and crust are one giant rock recycling machine. This is how rocks are distributed.

IGNEOUS ROCKS

“Ignis” = Latin for “fire”
Formed from the cooling of either magma or lava.
The most abundant type of rock.

1. Intrusive Igneous Rocks
Formed from magma below the ground
Usually have large crystal grains
They cooled slowly

2. Extrusive Igneous
Fromed from lava above the ground
Usually have small or no crystal grains
They cooled too quickly

3 Types of Igneous Rocks

1. Basaltic Igneous Rocks
Made from lava/magma that is low in silica and rich in iron and magnesium.
Rocks are dark-colored.

2. Granitic Igneous Rocks
Made from magma/lava that is high in silica and oxygen.
Rocks are light-colored.

3. Andesitic Igneous Rocks
Have a composition between basaltic and granitic.

SEDIMENTARY ROCKS

Formed from sediments (rock fragments, mineral grains, animal & plant remains) that are pressed or cemented together or when sediments precipitate out of a solution.
These sediments are moved by wind, water, ice or gravity.
Sedimetary rocks represent 7% of the Earth;s crust, but they cover 70% of the Earth’s surface.
Sedimentary rocks are fossik-carrying rocks.
Sediments turn to soild rock because water or wind breaks doiwn and deposits sediments (erosion & deposition)
The heavy sediments...

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