2 (g.a.c.) Metamorphic Rocks
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Igneous rock is any rock that forms from magma or lava. The name igneous comes from the Latin word ignis, meaning “fire.”
Sedimentary rocks form when sediment is deposited by water and wind. In erosion, running water, wind, or ice loosen and carry away fragments of rock. Eventually, the moving water, wind, or ice slows and deposits the sediment in layers. If water is carrying the sediment, rock fragments and other materials sink to the bottom of a lake or ocean. Deposition is the process by which sediment settles out of the water or wind carrying it.
Sedimentary rocks form when sediment is deposited by water and wind. In erosion, running water, wind, or ice loosen and carry away fragments of rock. Eventually, the moving water, wind, or ice slows and deposits the sediment in layers. If water is carrying the sediment, rock fragments and other materials sink to the bottom of a lake or ocean. Deposition is the process by which sediment settles out of the water or wind carrying it.
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Every metamorphic rock is a rock that has changed its form. In fact, the
word metamorphic comes from the Greek words meta, meaning “change,” and morphosis, meaning “form.” But what causes a rock
to change into metamorphic rock?
Heat and pressure deep beneath Earth’s surface can change any rock into metamorphic rock. When rock changes into metamorphic rock, its appearance, texture, crystal structure, and mineral content change. Metamorphic rock can form out of igneous, sedimentary, or other metamorphic rock. Collisions between Earth’s plates can push the rock down toward the heat of the mantle. Pockets of magma rising through the crust also provide heat that can produce metamorphic rocks. The deeper a rock is buried in the crust, the greater the pressure on that rock. |
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