Rocks
Crunch! Crunch! That is the sound rocks make when you are walking on them. You might think rocks are just boring things that randomly appeared but they are so much more than that. Rocks are substances that have been made up of different minerals that have been created above and below the earths surface that have could have been cooling for a long or short period of time depending on if it is an extrusive or intrusive rock. But, you will learn all about that in this section!
Igneous
Igneous Rocks
There are two types of igneous rocks. There are extrusive and intrusive. Extrusive is when the rock is formed outside of the earths surface, It is formed when lava gets shot out of the volcano and cools. When it has finally cooled it is an igneous rock. The second way intrusive is when it is formed beneath the earth’s surface, magma finds a crack in the earth and fills in that space, it cools very slowly and becomes an igneous rock. That is why not all igneous rocks look the same, because they are formed differently. But they don’t always stay as igneous rocks. They can become sedimentary and metamorphic rocks to. But you will learn about that and all about the cycle of rocks. Examples of igneous rocks are:
1. Quartz
2. Granite
3. Pumice
4. Obsidian
5. Basalt
There are two types of igneous rocks. There are extrusive and intrusive. Extrusive is when the rock is formed outside of the earths surface, It is formed when lava gets shot out of the volcano and cools. When it has finally cooled it is an igneous rock. The second way intrusive is when it is formed beneath the earth’s surface, magma finds a crack in the earth and fills in that space, it cools very slowly and becomes an igneous rock. That is why not all igneous rocks look the same, because they are formed differently. But they don’t always stay as igneous rocks. They can become sedimentary and metamorphic rocks to. But you will learn about that and all about the cycle of rocks. Examples of igneous rocks are:
1. Quartz
2. Granite
3. Pumice
4. Obsidian
5. Basalt
Sedimentary
Sedimentary rocks are formed in the water. Sedimentary rocks can be formed in two different ways. It can be formed by either compaction or cementation. Compaction is when for example, if mud and gravel were squeezed together it would form a rock…. A sedimentary rock! Cementation is when other materials are holding sediment together. Water, Wind and ice help move the sediment and help it form layers. The chemical change in water can also change them. These rocks don’t always stay the same. An example of a cementation rock is conglomerate. An example of changing is when you drive you might notice pot holes. Well, those pot holes have been crested from when sediments have been moved and formed in the cracks of the roads and have been expanding and break apart the road to create pot holes. An example of a compaction rock is shale. They can also change into metamorphic rocks to. Example of sedimentary rocks are:
1. Conglomerate
2. Sandstone
3. Shale
4. Limestone
1. Conglomerate
2. Sandstone
3. Shale
4. Limestone
Metamorphic
A metamorphic rock is formed when heat, pressure or fluids change one type of rock into another type of rock. It can be made from igneous or sedimentary. But, this process is slow and long. These changes happen below the earth’s surface. Examples of metamorphic rocks are:
1. Marble- was originally limestone, which is a sedimentary rock.
2. Slate- was originally shale, which was a sedimentary rock.
3. Gneiss- was originally granite, which was an igneous rock.
4. Quartzite- was originally sandstone, which was a sedimentary rock
5. Anthracite- was originally coal, which was a sedimentary rock.
1. Marble- was originally limestone, which is a sedimentary rock.
2. Slate- was originally shale, which was a sedimentary rock.
3. Gneiss- was originally granite, which was an igneous rock.
4. Quartzite- was originally sandstone, which was a sedimentary rock
5. Anthracite- was originally coal, which was a sedimentary rock.
Rock Cycle
The rock cycle it is the change in rocks. It shows how rocks change from one to another. It shows how metamorphic can change to both igneous and sedimentary, it also sows haw igneous can change to both sedimentary and metamorphic and that sedimentary can only change to metamorphic. But, how do they change from one rock to another? Well, Igneous rocks can change to sedimentary rocks by going through weathering and erosion and will end up being sediments. Next it will go through compaction and/or cementation. Then it will become a sedimentary rock. For it to become a metamorphic it will have to go through heat and pressure to change. When it becomes a metamorphic rock it can either go through weathering and erosion to become a sedimentary rock again, OR, it can can melt and become magma and go through a cooling process and once again become an igneous rock. It will be the same process for each rock, but it will just be starting at a different place.