There are three different kinds of rocks that are found in the layers of rocks. There is no specific order of the layers because the layers are always changing but one thing is for sure that the rocks in the bottom layer are the oldest rocks and the rocks at the top are the youngest layers.
The reason that the rocks on the bottom of the layers of rocks are the oldest is because rocks will continue to pile on top of each other. If there is one layer of rock on the bottom and another layer piles on top of it, the layer on the bottom is now the oldest and the layer on top is the youngest.
The layer on the top of the rock layer is the youngest layer of rocks. This will stay the youngest layer until another layer piles on top of it and then that will become the youngest layer.
There are three major types of rocks that form rock layers. These include metamorphic rock, igneous rock and sedimentary rock. These different types of rocks help to classify rocks by how they were formed but each of these different types of rocks have rocks that are made from them and so the cycle is always continuing.
Metamorphic rocks are rocks that are formed when there is a lot of pressure and a lot of heat. These rocks are usually found inside of the Earth’s crust because this is the area of the Earth where there is a lot of heat and pressure.
Metamorphic rocks are made up of different kinds of rocks such as:
Igneous rocks are rocks that are made when lava turns into magma. Igneous rocks are formed from magma. When the lava leaves the volcano, it forms magma and when magma cools, igneous rocks are made.
When magma cools down, it can be a fast cooling or a slow cooling. Depending on how fast or how slow magma cools depends on what kind of igneous rocks are formed.
Some igneous rocks include:
Sedimentary rocks are rocks that form when different debris and sediment are pushed together for a long, long time and then rocks form.
Most sedimentary rocks are carried to different places by water such as rivers or streams and they are taken to bigger bodies of water. These rocks are then left where they are and they sit there for years and years, sometimes even millions of years. After they sit for all of that time, they become sedimentary rocks.
Some sedimentary rocks include:
When there are many layers of sedimentary rocks, this is called a strata.
It is impossible to really name all of the rocks, so rocks are classified by how they are made. If a rock is made by pressure it is a metamorphic rock and if a rock is made by magma, it is an igneous rock and so on. The rocks are not made with exact formulas because they are made up of different things and some rocks have the same minerals.
The rock cycle is the way that rocks change over time. A rock can be a sedimentary rock and then change to a metamorphic rock. This happens because rocks are always changing. Even though it takes millions of years for rocks to change, they are changing all the time.
Here is how the rock cycle works:
The interesting thing about rocks is that they do not have to follow the rock cycle and often times, they do their own thing.
When the environment changes, it can cause rocks to change. Fore example, when there is a volcano that erupts, it shoots out magma and all kinds of ash. The ash hardens and the magma gets cooler.
Even though the ash is on top, it is still the newest layer and because of the change in the environment, there is now an older layer of rock underneath it.
We talk a lot about tectonic plates because they play such a huge role in the world changes. When there are rock layers that are moved or tilted, this can be because of the tectonic plates. As the plates change and move, it can cause the layers of rocks to move also. When this happens, the rocks will stay in a tilted formation until something happens that moves them back, and this is sometimes never.
Scientists use radiometric dating in order to tell how old rocks are. When a scientist uses radiometric dating, it is looking at the elements of the rocks that are radioactive. These rocks are able to give scientists a specific date that they were formed.
Radiometric dating is a process of reading how much radioactive material is in a rock.
Strata is when layers of rocks are formed. A stratum is many different layers. When a strata forms, it is usually a specific time or a specific place. When this happens, geologists are able to figure out where the rocks are from and when they formed.
When there is a normal rock stratum, the strata form horizontal or sideways layers. The rocks will sometimes become deformed because of pressure as there are more and more layers.
When there is heavy rain or other strong weather, there can be spaces that happen between the different strata. When this happens, these spaces are called unconformities.
Some strata formations repeat themselves such as a sandstone layer followed by a carbonate layer then a sandstone layer followed by a carbonate layer and this will repeat over and over again. When this happens, it is called a rhythmites.
A space rock is rocks that come from space. These rocks are called meteorites. Most meteorites are made up of iron and not the same elements of rocks on the Earth.