the rock cycle what is a rock?. answer a naturally occurring solid mixture of 1 or more...
TRANSCRIPT
The Rock Cycle
What is a rock?
Answer
• A naturally occurring solid mixture of 1 or more minerals/organic matter
• Rocks are always changing• New rocks form from old rocks = ROCK CYCLE
How can rocks help Humans?
HMMMMMMM…
Human Usage of Rocks
• Used for tools– Hammers, knives, arrowheads, spear points,
scrapers• Roads + monuments– Pyramids, capitol buildings
Weathering
• IS H2O, wind, ice, and heat break down rock• Breaks rocks down into fragments• These fragments will become part of
sedimentary rocks
Erosion
• Sediment is removed from its source• This is caused by H2O, wind, ice, + gravity
Deposition
• Process in which sediment moved by erosion is dropped and comes to rest is this.
• Sediment is deposited in bodies of water or areas of low-lying land
• Sediment will be pressed and cemented together to form sedimentary rock
Example of this
• Bryce Canyon is an example of weathering, erosion, and deposition
Heat and Pressure
• Sedimentary rock can also form when sediment is buried and squeezed by weight
• IF add heat to the process then the sediment rock can change to metamorphic rock
• If HOT enough to melt then will create magma when MAGMA cools then have igneous rock
Uplift
• Buried rock will eventually be exposed to Earth due to uplift and erosion
• Uplift is movement within the Earth that causes rocks inside the Earth to be moved to the surface
• Uplifted rocks will then go through weathering, erosion, and deposition
Rock cycle steps/paths
1. sedimentary rock-grains of sand and other sediments erode from hills
and Mts—wash into rivers—oceans—form the ocean floor—compacted together to form this
2. Metamorphic rock-Earth’s crust collide (tectonic plates) some rock is
forced downward—get intense heat + pressure= m. Rock
4. Igneous Rock-Magma rises (is less dense), cools= I. rock
5. Sediment -Uplift and Erosion expose the Igneous Rock—weathers, wears back into Sedimentary rock
Rocks changing
• So rocks are continually changing what time they’re due to the Earth’s process– Igneous –Sedimentary-Metamorphic
• The location of the rock is a huge factor is what the rock will change into– Surface- have weathering, erosion, deposition– Deep down- heat and pressure
Rock Classification
• Rocks are first divided into igneous, metamorphic, and sedimentary by how they form
• But then will divided them down even farther– Ex. Igneous- if cooled on Earth’s surface or below
• 2 main items scientist use is the composition and texture of rock to identify them
Texture
• The size, shape, and position of the grains that make up the rock = texture of it– Sedimentary= fine-medium, or coarse- depends on
size of grains– Igneous= fine to coarse-depends on how time
magma has to cool– Metamorphic = fine or coarse- depends on
temperature and pressure rock gets– Texture can also tell how rock was formed-look on
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