Chapter 22.1: The Geosphere Geology = The study of the planet E.’s composition & structure.
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Transcript of Chapter 22.1: The Geosphere Geology = The study of the planet E.’s composition & structure.
Chapter 22.1: The Geosphere
Geology = The study of the planet E.’s composition & structure
In Notebook …
1. Draw and label a diagram of Earth that shows its 3 major layers.
2. What is each layer made up of? (Rock? Metals? Gas? Something else?)
3. What happens to temperatures as you move from the surface to the center?
4. What happens to pressure as you move from the surface to the center?
How do we know about Earth’s interior if we can’t see it?
1. Seismic (earthquake) waves Waves travel at different speeds in different mediums and materials
2. Samples of the shallow mantle fr. Volcanoes.
People used to think…
- Earth was a few thousand years old.
- Earth never changed.
Geologists discover that:
- Earth is billions of years old
-Earth is always changing (Mt. building, continents move, etc.)
Geosphere: Earth’s LayersMajor Layers1. Core2. Mantle3.Crust
Why Layers?• Separation due to DENSITY DIFFERENCES.
• While E. was molten, heavy things sank to center (metals); light things (silica rocks) floated
Early Earth: Origins: http://www.youtube.com/watch?v=asEiF05f1SwPart 2; 4 min http://www.youtube.com/watch?v=8OfNefK9o84&feature=related
Core Mantle Crust
Iron (85%)
Nickel (11%)
Sulfur (4%)
Density: ~11 g/cm3
Density: ~5 g/cm3
Density: ~3 g/cm3
Temperatures & Pressures
• Increase with depth
(Gets hotter with more pressure fr. Crust core)
The Composition of the Earth
CrustTypes of Crust
A. Continental• Less dense• Thicker • Older• Granite
B. Oceanic• Dense rocks like
basalt• Thinner• Younger• Basalt
Made of:•Light Rock layer (silicates)• Thinnest layer
Abundances of Elements in Earth’s
Crust
Silicon & Oxygen compounds = silicates
( ~ 74%)
These make crust light!
“Moho” =
boundary b/w crust & upper mantle
The Mantle• Composition:
Heavy Rock
• Less silica; more iron
3 Divisions of the Mantle
Lithosphere = Upper mantle + Crust“Plates”, Rigid Slabs
Asthenosphere = Softer, moving hot rock (Convection Currents)
Mesosphere = Stiffer rock near core
Convection in the Mantle (astheno)•Driven by temperature & density differences
Hot rock near core = less dense = rises
Cooler rock near crust = dense = sinks
Core• Composition: Heavy
Metals! (densest)
• Iron & Nickel
• Hottest Layer
• Most pressure
2 Layers of Core
• Inner Core– Solid iron and nickel– High pressure keeps it
solid
Outer Core• Liquid• High temp. keeps it liquid• Responsible for Earth’s magnetic field
Iron (85%)
Nickel (11%)
Sulfur (4%)
Density: ~11 g/cm3
The Core
Label Each Layer.
Be able to describe each layer: What is it made up of?; Is it solid? Liquid? “taffy-like”; What happens to temps., pressures, and density as you move through layers?
Self Quiz
1. Compare how constructive and destructive forces affect Earth’s surface.
2. List the 3 layers of Earth.3. Which layer has currents of moving rock?4. Which is the most dense layer?5. Which layer is made of light rocks like silicates?6. Which is more dense: Continental or Oceanic
Crust?7. Which layer of the mantle is part of Earth’s
plates?8. Which layer is made of heavy metals?
Answers to Self Quiz1. Constructive forces build new land/crust and
destructive forces destroy crust.2. Crust, Mantle, Core3. The asthenosphere – which is in the mantle4. The core5. The crust5. Oceanic crust is denser (but thinner)6. The upper mantle (and the crust make up the
lithosphere, or plates)7. CoreHow the Earth was Made:Part 1: http://www.youtube.com/watch?v=V1kTIZeq1Ck;Part 2: http://www.youtube.com/watch?v=SoRqVDQXj-AEarly Earth & plate tectonics http://www.youtube.com/watch?v=QDqskltCixA