decribe the composition and nechanisms

of the earth crust

http://mediatheek.thinkquest.nl/~ll125/en/crust.htm

ms suehow do u post links it wouldnt let me it said i had to like contact someone or something

Only a few of us regular volunteers can post links. We want to keep this forum safe for everybody.

but i was posting a link to help sumone lol

The Earth's crust is the outermost layer of the planet, consisting of rocks, minerals, and other geological materials. It is divided into two major types: continental crust and oceanic crust.

1. Continental crust: This is the thicker type of crust that makes up the continents. It is composed mainly of granitic rocks, which are light-colored and less dense than oceanic crust. Continental crust can be as thick as 70 kilometers in some places.

2. Oceanic crust: This is the thinner type of crust found beneath the oceans. It is primarily composed of basaltic rocks, which are dark-colored and more dense than continental crust. Oceanic crust is typically about 5-10 kilometers thick.

Both types of crust are made up of various minerals, including silicon, oxygen, aluminum, calcium, sodium, and potassium. These minerals combine to form different types of rocks, such as granite in continental crust and basalt in oceanic crust.

The mechanisms responsible for the composition and formation of the Earth's crust are:

1. Plate Tectonics: The Earth's crust is divided into several large and small plates that float on the semi-fluid layer beneath called the mantle. These plates constantly move and interact with each other. This movement leads to various geological processes like volcanic eruptions, earthquakes, and the formation of mountain ranges. It also influences the composition and distribution of rocks in the crust.

2. Magma Generation: The Earth's mantle is made up of hot, partially molten rock called magma. Magma is generated through processes like mantle convection and decompression melting. When magma rises towards the surface, it can cool and solidify, forming new crust either through volcanic activity or solidification beneath the ocean floor.

3. Weathering and Erosion: Over time, the Earth's crust is subjected to weathering and erosion processes caused by wind, water, ice, and chemical reactions. These processes break down rocks into smaller particles and transport them to new locations. Weathering and erosion play a crucial role in the cycling of minerals and the formation of sedimentary rocks.

4. Metamorphism: The Earth's crust can also undergo metamorphic processes. During metamorphism, existing rocks are subjected to high temperature and pressure, causing their minerals to rearrange and change. This can result in the formation of different types of rocks, such as marble from limestone or gneiss from granite.

Understanding the composition and mechanisms of the Earth's crust requires a combination of geological studies, including field observations, laboratory experiments, geophysical surveys, and the analysis of rock samples collected from various locations around the world.