Basic Plate Tectonics Plate Tectonic Theory Inside the

Basic Plate Tectonics Plate Tectonic Theory

Inside the Earth • Earth’s 3 Main Layers o Crust, Mantle, Core • Earth’s 5 Main Spheres o Lithosphere, Asthenosphere, Mesosphere, Inner and Outer Core • Lightest materials make up the crust • Densest material make up the core

• Crust o 5 -100 KM thick thinnest layer o Two types • Continental o Similar to granite o Avg thickness of 30 KM • Oceanic --Denser than continental crust --Avg thickness of 5 -8 KM

• Mantle o Largest Layer 2, 900 KM thick o 67% of Earth’s Mass o Magma molten rock samples found on ocean floor in active volcano vents o Iron and Magnesium Why do you think the best samples from the Mantle are from the ocean floor? Answer: Because the Oceanic crust is thinnest and easiest to puncture with tectonic forces

• Core o Iron and Nickel • Also a little bit of Sulfur and Oxygen o 33% of Earth’s mass o Diameter of 6, 856 KM o Bigger than the whole planet of Mars! If Iron and Nickel make up the core, what two elements make up the Mantle? Answer: Magnesium and Iron

• Lithosphere o “Rock Sphere” o Made up of crust and tectonic plates o 15 -300 KM • Asthenosphere o “Weak Sphere” o Soft layer that flows 1. 25 inches per year o 250 KM • Mesosphere o “Middle Sphere” o Strong, lower mantle o 2, 550 KM

• Outer Core o Liquid layer beneath Mantel o 2, 200 KM • Inner Core o Solid, Dense Core o 1, 128 KM o 6, 000 Deg. C, Hotter than the Sun’s Surface! Which layer do you think consists of the magma that punctures the ocean’s floor or exists in volcanoes? Answer: The Asthenosphere consists of magma, a molten putty like solid that is constantly flowing

Assignment for Day One 1. What is the difference between continental and oceanic crust? 2. How did scientists determine the structure of the interior of the Earth? 3. Explain the difference between the crust and lithosphere. 4. In two paragraphs, discuss the three spheres of the mantle and two layers of the core 5. The core is made of iron and nickel that is constantly rotating. How does this affect our poles? (Hint! “Stick it to the fridge with a ______”)

Day Two: • Pangaea- Super Continent • Panthalassa - The Super Ocean • One large land mass and large Ocean from Ancient times

• Laurasia o North America o Asia o Europe • Gondwanaland o o o South America Africa India Antarctica Australia

Seismic Waves • Two types of Seismic Wave o Body Waves o Surface Waves • Two types of Body Waves -Primary Waves -Back and Forth motion -S Waves -Secondary Waves -Up and down motion

• Seismologists use Seismic Waves to determine the density of each sphere by how fast they travel o Speed of the waves depends on density of the layer. o More Dense= More Time What are the two types of Body Seismic Waves? P and S Waves are the two Body Waves Which interior layer or sphere does it take longest for the Waves to travel through? Why? The Inner Core, because it is the densest being a molten solid mass of Iron and Nickel

• Tectonic Plate- plates in the lithosphere that move around on top of the Asthenosphere • Main Ten: 1. Pacific Plate 2. North American Plate 3. Cocos Plate 4. Nazca Plate 5. South American Plate 6. African Plate 7. Eurasian Plate 8. Indian Plate 9. Australian Plate 10. Antarctic Plate Was the Indian Plate Always with the Eurasian Plate? Answer: NO, the collision formed the Himalayans

Continental Drift • Alfred Wegener o Wrote a book in the 1900 s suggesting continental drift • Continental Drift – theory that the continents are continually moving together and apart o Proven by species, rock, and climate similarities

BPT- Day 2 Assignment 1. What was the name of the super ocean? 2. Was the Indian plate always connected to the Eurasian plate? If not, what was formed? 3. How was theory of continental drift proven? 4. What is the difference in the types of movement between the two types of body waves? 5. What was the name of the super continent?

Surface Features • Mid-Ocean Ridges – underwater mountain chains where sea-floor spreading occurs o Ex: Mid Atlantic Ridge • Sea-Floor Spreading – the process by which new oceanic crust is formed o Magma rises and cools forming new crust o Old crust becomes pulled down into the magma

Is the Oldest crust at the ridges or at the continental shores? Answer: The oldest crust is at the shores because the newest crust is formed with the upwelling of magma at the ridges where the tectonic plates have separated. The old plates are then pulled beneath the continental plates

Magnetic Reversal • Magnetic Reversal- when the poles change place o Ex: South Pole become located in the North, and the North Pole becomes located in the South o Evidence seen on the Sea Floor o Magma brings up magnetic materials that align with the current polarity of the Earth

What element of magma considered magnetic and thus showing the polarity of the Earth by aligning according to the poles? Answer: The Mantle is made of Magnesium and Iron is notoriously magnet

Mountain Building • Deforming the Earth’s Crust o Stress- The amount of force applied on an object o Compression- The squeezing of an object, like when plates collide o Tension-The stretching of an object, like when plates separate/grind o Fold- When rock layers bend due to stress 1. Anticline 2. Syncline o Fault- A break in the Earth’s surface 1. Normal 2. Reverse/Thrust 3. Strike-Slip

Types of Faults Types of Folds

• Types of Mountains o Folded Mountains • Rock layers squeezed together and pushed up • EX: Appalachian Mts. o Fault Block Mountains • Rock layers tilted and pushed upward • EX: Himalayans Mts. o Volcanic Mountains • Mountains formed when molten rock erupts on to the Earth’s Surface • EX: Hawaiian Islands

BPT- Day 3 Assignment 1. What is the difference between an anticline and syncline? 2. What are three types of faults and how do they differ from each other? 3. What the three types of mountain formations and how do they differ? 4. How do compression and tension differ? 5. How does sea-floor spreading reveal magnetic reversal? 6. Who invented the first theories of continental drift?