nm500 composition

    
    The Crust or Lithosphere
    
    The Earth is made up of layers that each possess their own unique characteristics. One layer is known as the Crust or Lithosphere. The crust is composed of various minerals, such as feldspar, quartz, and mica, among others. It is the outermost layer of the Earth and is what we interact with every day. The lithosphere is composed of two layers. The first layer is the oceanic crust, which is made up of mainly basalt, a dark colored igneous rock, and the second layer is continental crust, which contains a variety of sedimentary and igneous rocks.
    
    Tectonic Plates
    
    The lithosphere is broken up into many separate plates, known as tectonic plates. The lithosphere is divided into seven major plates, along with a few smaller plates. These plates are constantly moving and shifting, a process known as plate tectonics. This movement is caused by convection in the mantle which results in the plates “floating” on the magma below. This movement of the plates is responsible for the creation of mountain ranges and volcanoes, as well as for earthquakes.
    
    The Asthenosphere
    
    Beneath the lithosphere is the asthenosphere, which is part of the Earth’s mantle. This layer is composed mainly of solid rock, but with a slight flexibility to it due to its high temperatures. The asthenosphere is thought to be the layer which allows for the movement of tectonic plates. This is due to its semi-molten nature, which allows for the plates to slowly slide over each other.
    
    The Outer Core
    
    The outer core is the layer of Earth beneath the asthenosphere. It is composed of liquid iron and nickel, and is believed to generate the Earth’s magnetic field. This layer is also thought to be responsible for earthquakes, as seismic waves will travel through it faster than they will through the more dense layers below.
    
    The Inner Core
    
    The inner core is the very center of the Earth, and is composed mainly of iron and nickel. It is believed to be even more solid than the outer core and is made up of a much higher percentage of iron and nickel. This layer is thought to be the source of our planet’s heat, which is necessary for the proper functioning of life.
    
    The crust, or lithosphere, is the outermost layer of the Earth and it is what we interact with every day. It is divided into several tectonic plates, which are constantly shifting and moving, allowing for the birth of mountain ranges and volcanoes. Beneath the lithosphere is the asthenosphere and the outer core, with the inner core being the very center of the Earth. This layer is responsible for the planet’s heat, which makes life possible. Understanding the various layers of the Earth is key to understanding our environment and how it continues to change and evolve.