LandForms


 * Next to each land form put what causes it to be created feel free to make any changes needed**


 * Mountains-** The earth’s crust is made up of gigantic plates. These plates will create a fault line wherever they meet another plate. When these fault lines start pressing against each other, then they will push the land upwards in one way or another. When this land reaches up into the sky, you have a mountain.[]


 * Rift valle**y**-** A new ocean begins when hot mantle material begins to move upward beneath a continent. Geoscientists are still not certain about why that happens. The lithosphere of the continent bulges upward and is stretched sideways. Eventually its breaks along a long crack, called a rift. Magma rises up to feed volcanoes in the rift. As the rift widens, the ocean invades the rift. A new ocean basin has now been formed, and it gets wider as time goes on. []


 * Volcano-** Basically, it is a space that allows molten rock called magma to rise from under the Earth to its surface. When this magma erupts from a volcano, it is known as lava. This is the substance that forms the cone around the space.[]


 * Trench-** Ocean trenches are formed at a specific type of plate boundary called a subduction zone. These zones occur when an ocean plate collides with another ocean plate or with a continental plate.[]

 1.) As a lithospheric slab is being [|subducted], the slab melts when the edges reach a depth which is sufficiently hot. Hot, remelted material from the subducting slab rises and leaks into the crust, forming a series of [|volcanoes] . These volcanoes can make a chain of islands called an "island arc". Examples of island arcs are the Japanese islands, the Kuril Islands, and the Aleutian Islands of Alaska, shown here. Island Arcs are formed on the opposing edge of a subducted slab. For each case, there is an associated subducting slab and a [|trench] . The trenches for these island arcs can barely be made out in this map. 2.) The second way in which islands are formed is via [|plumes] or hot spots in the lithosphere. The Hawaiian Islands are an example of this type of island formation. In this case, there is no associated subducting slab. http://www.windows2universe.org/earth/interior/island_formation.html
 * island arcs-** There are two ways in which a group of islands can form.

**This is an image the ocean floor of the Earth, showing island arcs being formed. Click on image for full size //Image from: NOAA/NESDIS/National Geophysical Data Center, Boulder, CO//**


 * mid ocean ridges-** A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary. http://www.sciencedaily.com/articles/m/mid-ocean_ridge.htm