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1. Rocks
2. There are three types of rocks: Igneous - granite
Metamorphic - gneiss
Sedimentary - limestone
3. Whats an igneous rock?!? Igneous comes from the Latin ignis, or fire.
Igneous rocks form as molten rock cools and solidifies.
The parent material for igneous rock is magma
and magma that reaches the Earths surface is called lava.
4. Igneous rocks are classified into two groups depending on where they solidify: Igneous rocks that form when molten rock solidifies on the surface are called extrusive, or volcanic.
Igneous rocks that form before reaching the surface are called intrusive, or plutonic.
5. Magma comes from inside the Earth
6. Igneous rocks are classified in 3 basic categories: Granitic
Basaltic
Andesitic
7. Granitic rocks
Contain a lot of quartz and feldspar which give most granitic rocks their light color.
Lower density
Include:
pumice
obsidian
8. Basaltic rocks
are dense and tend to be
...dark in color
Includes:
Basalt
and Scoria
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and the last is Andesitic. The crystals are medium to fine grain.
Color can have a salt and pepper look.
10. Whats a Sedimentary rock?!? Sedimentary comes from the Latin sedimentum which means settling
75% of all rocks on the surface are sedimentary (
most of the rocks below the surface are igneous).
Sedimentary rocks form by the processes of compaction and cementation.
11. What makes the sediment? First, the weathering of existing rocks begin the process.
Next, erosional agents such as running water, wind, waves, and ice remove the remains of weathering.
Sediment gathers and starts to form layers.
These layers start to stick together and form solid rock.
12. Lets see how sedimentary rock is formed
13. Types of Sedimentary Rocks. Detrial or Clastic sedimentary rocks:
Formed from the accumulation of particles that are compacted or cemented together.
Particle size is used to distinguish these types of rocks.
Common detrial sedimentary rocks, in order of size are shale, sandstone, and conglomerate or breccia.
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Types continued
Chemical sedimentary rocks:
Formed when dissolved substances
precipitate out of the solution.
is left when the solution evaporates.
Examples of chemical sedimentary rocks include: limestone, chert, rock salt, and gypsum
Rock salt and gypsum are called evaporites.
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and finally. Organic sedimentary rocks:
Formed from the remains of once-living (now dead) things. These include remains of clams, mussels, coral, and snails.
The shells of these animals contain calcite, a major component of rocks.
Examples include: limestone, coquina, and chalk.
18. Metamorphic Rocks
Metamorphism means to change form.
Agents of metamorphism include:
Heat
Pressure (stress)
Chemically active fluids (like water)
The degree of metamorphism and involvement of each agent varies.
19. The Agents Heat gives energy to cause chemical changes that result in recrystallization of mineral.
Pressure makes the rock break, shear, or become plastic (with heat).
Chemically active fluids can promote recrystallization or the formation of completely new minerals. (ion exchange)
20. What kind of changes can you see? When pressure and heat are just right particles within the rock can recrystallize and realign.
This realignment causes the rock to have a banded or layered texture called foliation.
Examples include: slate, phyllite, schist, gneiss.
21. Foliation
22. Nonfoliated texture
Some rocks, like those of one mineral, (limestone) are nonfoliated.
The small crystals may combine to form larger interlocking crystals instead.
Examples include: marble and quartzite
23. How does metamorphism happen
24. The Rock Cycle
