This week we learned about the layers of earth and looked at pictures with different layers. We worked as a group to determine which layer we thought came first and why. For our lab, we looked at different types of sands underneath a microscope and took a guess on what we thought they were based off their properties/characteristics. Below on the left side are our thoughts on what each one is.. on the right side side are the correct answers.
1) Glacier - Water
2) Wind - Wind
3) Wind - Water
4) Glacier - Water
5) Glacier - Water
6) Wind - Wind
7) Glacier - Glacier
8) Water - Water
9) Water - Water
10) Glacier - Water
11) Water - Water
Wind Erosion can only move small particles but they can eat away at larger particles. Wind erosion characteristics: Young rivers carve down, have lots of energy, and tear apart the land, eroding all that it can due to energy from gravity. They can move material of any size and have similar characteristics: White water, boulders, fast flowing.
Old rivers meander from side to side, have less energy, and carry fine sediment. Think of the Mississippi river. They have oxbow lakes and they "eat" at the banks of the river. Mature rivers are in between the two above. Wind is the weakest. Glacier is the strongest and can move giant boulders.
Characteristics of water erosion: Headwater streams swiftly flow down and steep mountain slopes and cut deep, v-shaped valleys. Waterfalls and rapids occur in this zone.
Glacier erosion: Moves huge particles, think of the brain rock on campus, that came from Canada during the last Ice Age. There are two kinds of Glaciers, mountain and Continental. Glacial erosion makes up a lot of the formations you see in Iowa and in the mountains.
Textbook:
Weathering is the breakdown of rocks on Earth’s surface. There are two types of weathering:
Mechanical: also known as physical weathering, rock is broken down into smaller fragments due to water, wind, or other conditions such as temperature and pressure changes
Chemical: chemical reactions change the molecular structure of the rock
After the rocks are broken down through weathering, erosion can occur. Erosion is the process by which the small bits of rock are transported to a new location. Finally, deposition occurs when the particles are added to or deposited at a new location. These three processes act as a cycle, continually breaking down and building up different parts of Earth’s landscape.
Intrusive Igneous Rocks Extrusive Igneous Rocks
When magma cools underground, it cools more slowly. Since it is inside Earth, it is well protected and forms larger crystals. This is called an intrusive rock. When magma cools in water or on the surface of Earth, like after a volcano erupts, it cools more quickly and forms smaller crystals. This is called an extrusive rock.
Rock Cycle: The key processes in the rock cycle are heat & pressure and weathering & erosion. Each type of rock can undergo different changes that affect its form and the type of rock it is.
Igneous rocks:
Can undergo heat and pressure to become a metamorphic rock
Can undergo weathering and erosion to become a sedimentary rock
Can melt and become magma again. Then, it will cool and re-form as an igneous rock.
Sedimentary rocks:
Can undergo heat and pressure to become a metamorphic rock
Can undergo weathering and erosion, thereby breaking apart into sediments. Then, these sediments can be compacted again into sedimentary rocks.
Can melt and become magma or igneous rock
Metamorphic rocks:
Can undergo heat and pressure to transform into another metamorphic rock
Can undergo weathering and erosion to become a sedimentary rock
Can melt and become magma and igneous rock
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