Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Plate Tectonics Unit
Study Guide
| Term | Definition |
|---|---|
| Pangaea | The supercontinent that existed 200 million years ago propsed by Wegener. |
| Fossils | Matching ______ of dinosaurs that existed over 200 million years ago are found along adjacent coastlines. |
| Rock Layers | Certain mountain rangers and rock layers along matching coastlines math one another. |
| Climate Record | Coal can be found in some locations near the poles today, but must have formed near the equator. Glacier evidence can be found in some locations near the equator today, but must have formed near the poles. |
| Harry Hess | ____ _____ was a professional geologist and navy sub commander who discovered the sea floor was spreading along the mid-ocean ridges. |
| Alfred Wegener | ______ ______ was an amateur geologist who realized that many of the Earth's continents seemed to fit together like a puzzle. He collected fossil evidence and determined that the Earth's continents were once all connected and drifted apart over time. |
| Mid-Ocean Ridges | ___-___ ____ are mountain changes that form on the ocean floor when magma pushes it way to the surface. |
| Oceanic Crust | Very dense and thin die to water pressure condensing the crust over millions of years. |
| Continental Crust | Thick and less dense than oceanic crust. |
| Lithosphere | The rigid portion of the crust that makes up the Earth's plates. |
| Asthenosphere | The flowing portion of the mantle below the lithosphere, on which the plates float. |
| Convection Currents | The rising and sinking of heated magma in the asthenosphere which causes the plates to move. |
| Divergent Boundaries | Plates move apart from one another - Occurs along oceanic crust, producing mid-ocean ridges. |
| Continental-Continental | Continental plates collide with continental plates, squeezing the rock together and forming mountains. |
| Continental-Oceanic | Oceanic plates collide with continental plates and the denser oceanic plate subducts below the continental plates, forming trenches at the subduction zone and volcanoes along the coastline |
| Oceanic-Oceanic | Oceanic plates collide with oceanic plates and the denser of the two plates subducts below the other forming trenches and volcanic islands |
| Transform Boundaries | Plates move side-by-side past one another, and friction between the plates causes them to bend and release energy causing earthquakes |
| Cause of Earthquakes | At transform and convergent (subduction) boundaries, plates moving past each other cause stress to build up and then release energy causing earthquakes |
| Elastic Rebound Thearoy | As plates try to move past each other, they begin to bend as stress builds up. Eventually, the plates move past and the plates rebound back into shape causing an earthquake |
| Seismograph | A device used to record and measure seismic waves |
| Primary Waves | _____ _____ move faster than S waves and are compressional waves. They move similar to energy through a slinky. |
| Secondary Waves | _____ _____ move slower than P waves and are shear waves. They move similar to energy through a rope. |
| Locating the Epicenter | To locate an earthquake’s epicenter, you need to use the difference in arrival time of P waves and S waves to find the distance. Then you need to use triangulation to combine three distances and find a single point. |
| Richter Magnitude Scale | Scale measures the strength of seismic waves based on wave amplitude. Scale goes from 1-10 |
| Modified Mercalli Scale | Scale measures the intensity of the earthquake based on the type of damage that occurs. Scale goes from I to XII. |
| Bedrock vs Poorly Consolidated Ground | Bedrock is solid and lessens earthquake damage. Poorly consolidated ground increases earthquake damage. |
| Earthquakes in the United States | Most active fault lines in the US are along the west coast, specifically in California. Most of the Northern U.S are in the middle of the North American plate and are low risk for major Earthquakes. |
| Tsunami | A large wave produced by Earthquakes which form on the ocean floor. Tsunami can flood coastal regions, destroying everything in their path. |
| Volcano | Any structure that brings magma from below the surface, erupting lava onto the surface. |
| Magma | Melted rock located below the Earth’s surface |
| Lava | Melted rock located above the Earth’s surface |
| Subduction | One plate moves under another causing magma to be produced and makes volcanoes |
| Hot Spots | Magma rises from below the Earth’s plates in a location that is extremely hot |
| Viscosity | “Thickness” A fluid’s ability to resist flow. |
| Mafic | Made from rocks rich in iron/magnesium, this types of magma is thinner than felsic magma. Found primarily at hot spots. |
| Felsic | Made from rocks rich in silicates (feldspar, quartz), this type of magma is thicker than macific magma. Found primarily at subduction zones. |
| Pahoehoe | Cools slowly and has a ropy texture |
| AA | Cools quickly and has a jagged texture |
| Volcanic Dust | Smallest particle- Less than 0.25 mm in diameter |
| Volcanic Ash | second smallest particle - 0.25-2 mm in diameter |
| Lapilli | third smallest particle - 2-64 mm in diameter |
| Volcanic Bombs | Largest particle- >64 mm in diameter |
| Shield | Very wide or broad, very runny (low-viscosity) lava, non-explosive due to low gas content: Kilauea (Hawaii) |
| Cinder Cone | Short and steep, cinders (medium-viscosity) lava, medium explosiveness: Paricutin (Mexico) |
| Composite | Very tall and mountainous, Lava is mostly pyroclasts (high-viscosity), highest gas content, very explosive: Mount St. Helens (United States) |
| Mt. St. Helens | Located in Washington State, Major Eruption in 1980 when North Side of the Volcano blew off causing a massive landslide and covered the region with pyroclastic flow. The flow knocked down trees and destroyed life in the region. 57 people killed in the bla |
Created by:
HannaW04
Popular Earth Science sets