Custom «Continental Margins» Essay Paper Sample

The earth materials are composed of the soil, rocks, water and the gases found in the atmosphere. The materials also possess different chemical properties. These properties make them very useful in a variety of ways. These are the resources that humans use for consumption. Minerals refer to the combination of elements that possesses a unique structure that forms an inorganic compound. A greater part of the crust of the Earth is composed of several minerals. Minerals help form rocks such as granite. Rocks are made up of minerals. Rocks also have different colors when one will be able to look closely at them. The rocks are composed of not only one kind of mineral but also different kinds of minerals. Minerals are not formed from inorganic compounds. They must occur naturally and contains the same chemical composition with the organic compound that it originates. Minerals have with them a crystalline structure. Because of this type of structure, specific atoms have the same repeated pattern.

Weathering and erosion affect the formation of rocks on earth. Weathering and erosion break down larger rocks into smaller rocks. The composition of rocks can also be changed. There are three basic forms of weathering. One type is mechanical or physical weathering wherein clasts of rocks and mineral are produced. The resulting rocks are smaller than the original ones but have the same type of composition. Mechanical weathering is the physical disintegration of rocks and several factors can bring about chemical weathering. These are the development of salt crystals, frost and root action. Chemical weathering is another form in which the rocks produced are also in smaller pieces but contains a different chemical composition from the different rock. The minerals that resulted from chemical weathering have been transformed to be appropriate for surface conditions. Clay is the most common product of chemical weathering (Ernst 75).

There are three types of rocks that compose the earth. The first type of rock is called the igneous rock. These are rocks that are made of magma and lava that have already cooled down. Magma and lava are also rocks that have a very high temperature. They move like liquid because they are so hot. Both the lava and magma are molten rock. The difference is that the magma originates from the underground while lava travels above the ground. Granite is an example of a common igneous rock. Another type of rock is the sedimentary rock. Sedimentary rocks can form in three different ways. Clastic sedimentary rocks are the rocks that come from the material of other rocks that have also broken down. Erosion will occur when the rock has been exposed to other elements of the earth. There will be pieces of the rock that were the results of the erosion. These little pieces will begin to accumulate in the lakes and oceans. With the passage of enough time and with the right amount of pressure, these little rock pieces will be cemented and compressed together in order to form a larger rock (Dayton 8). This rock that came from the little pieces of rocks can be called as the clastic sedimentary rock. Chemical sedimentary rocks are the rocks when the water that is rich in chemicals will evaporate and the material will be left behind. Organic sedimentary rocks are the rock formations that came from the fossils. These rocks were from the remains of animals specifically the bones and the shells that have hardened and compressed. Metamorphic rocks are rocks that have been subjected to extreme heat and pressure deep inside the earth. The heat and pressure will cause the minerals contained in the rocks to morph into other types of minerals. As a result, the rock has been transformed into an entirely different rock. This rock is now called a metamorphic rock because it has formed out of extreme heat and pressure (Ernst 67).

The rock cycle is powered and caused by the movement of the plates of the earth. The crust is composed of several plates that move slowly and float around the mantle top. The movement of the plates is due to the convection currents that are circulating in the mantle. The spaces and the holes on the earth where the magma will rise will cause the earth's plates to move apart from each other. These areas wherein the plates move apart are called the rifts or the divergent plate boundaries. This ridge has caused both the North and South America to move away from Africa and Europe. The areas where the magma will begin to cool down and descend back to the core of the earth. The continental crust will go down along with the magma. These places are said to be the convergent zones. Because there is a collision of the plates, deep trenches are formed at the very bottom of the ocean. The Marianas trench is considered to be the deepest with a distance of seven miles below sea level. The rocks that are pulled down along with the crust will then be subjected to pressure and heat. These rocks will be transformed into metamorphic rocks. If these rocks will be pulled down even more, they may melt and turn into magma. Magma will then travel to the surface and cool down. The rocks that are already cool have been changed into igneous rocks. The tectonic plates help in the rock cycle processes (Codispoti 2008). Aside from the rock cycle, land forms were formed due to the interaction of the destructive and constructive forces of the earth. Constructive forces include the deformation of the crust, volcanic eruptions and the accumulation of the sediments. Destructive forces are erosion and weathering.