B. Each main layer is subdivided into more layers
1. The core is divided into....
a. solid inner core
i. 1,250 km thick solid inner core
ii. Temperature = 5500 to 7000 degree C (almost as hot as the sun)
iii. Composed of nickel and iron, solid due to extreme pressure
b. Liquid outer core
i. 2,200 km thick liquid outer core
ii. Temperature = 6100 to 4400 degree C
iii. Composed of molten nickel and iron
iv. outer core spins, creating the Earth's magnetic field that protects from solar wind
a. solid inner core
i. 1,250 km thick solid inner core
ii. Temperature = 5500 to 7000 degree C (almost as hot as the sun)
iii. Composed of nickel and iron, solid due to extreme pressure
b. Liquid outer core
i. 2,200 km thick liquid outer core
ii. Temperature = 6100 to 4400 degree C
iii. Composed of molten nickel and iron
iv. outer core spins, creating the Earth's magnetic field that protects from solar wind
2. Mantle
a. Lower mantle
i. a.k.a., mesosphere ii. 2100 km thick iii. Hot, semi-solid rock iv. Consistency of hot asphalt b. Upper mantle i. Composed of two parts 1. Asthenosphere is semi-solid or 'plastic' and is ~700 km thick 2. Uppermost part of the mantle is solid and ~100 km thick We always imagine that the mantle is like a blended "smoothie" of molten rock, but recent evidence suggests otherwise.
"To get at what this finding means for geology, picture a smoothie. No—go farther back than that and picture the blender carafe full of fruit, ice, milk and other ingredients. That’s like the mantle—discrete ingredients, as different from each other as a strawberry is from a blueberry. The fully blended smoothie is like the mid-ocean ridge lava. It’s fully mixed. At some point between the deep mantle and the mid-ocean ridge [where lava creates new ocean floor], Earth turns on the blender. Lambart says that her results show that at the very top of the mantle, the mixing hasn’t happened yet. The blender, it turns out, doesn’t turn on until somewhere in the crust." How Earth's Mantle Looks Like a Jackson Pollock painting |
3. Crust
a. Oceanic crust
i. Narrowest, 0-10 km ii. Made mostly of dense basalt iii. 2/3 of the Earth's surface iv. Younger than continental crust b. Continental crust i. 35-70 km thick ii. Made mostly of less dense granite iii. covers 1/3 of Earth's surface c. Combined with the uppermost part of the mantle = lithosphere |
Other "spheres"
Remember that we learned that the biosphere is that part of the Earth that contains living things - from the deepest parts of the ocean to the atmosphere (the layers of gases which surround the earth). The hydrosphere is the layer of the earth where water is found. The oceans are where most of the earth's water is found, but water can also be found in lakes, rivers and below the ground. Water is also an essential habitat resource.
Using Oobleck as a model for the asthenosphere
Mixing cornstarch and water creates a 'Non-Newtonian' fluid that acts like a solid and a liquid, depending on the pressure you place on it. We'll play with this in lab and discover it's interesting properties. We use Oobleck as a model to help understand the asthenosphere, which flows like hot asphalt and is thought to be responsible (at least in part) for tectonic plate movement. The video on the right shows how Oobleck reacts to vibrations coming from a bass speaker.
|
|