Plate Tectonics: Cracking the Surface & Digging Deeper Fill in the Blank Notes https://docs.google.com/document/d/1cRsXgQkGNjt2Us1gr0km422duA8y8TfEzkC7Amj03xM/edit Nearpod Notes
Learning Target: I can differentiate between convergent, divergent and transform boundaries.
Theory of Plate Tectonics Earth’s plates are in constant, slow motion Between 2.5 and 15 cm per year! Explains how plates move and form Since you’ve been alive, plates have moved more than 180 centimeters!!!
Geologists came to the conclusion in the 1960’s that the Earth’s lithosphere was broken up into large pieces called plates that are moving relative to one another. Theory of Plate Tectonics continued...
The lithosphere floats upon the asthenosphere (upper mantle).
Continental crust is less dense than oceanic crust. Continental crust is composed of granite. Oceanic crust is composed of basalt. The crust and upper layer of the mantle together make up a zone of rigid, brittle rock called the lithosphere. The continental crust is composed mostly of granite which allows them to ride on the denser oceanic plates of volcanic basalt.
Plate Movement Plate motion is the result of the movement of material in the upper mantle, which drags the overlying plates above. Convection currents take place in the mantle
Convection Currents The transfer of heat by movements within a fluid (gas or liquid) hot rises, cool sinks Convection currents within the mantle cause the plates to move
Continental Drift The process continues as the current earthquake/volcano hot spots of the world reflect the edges of the moving plates atop which the continents sit.
Quiz Time! 1. The plates move along the top of the A. core B. asthenosphere C. crust D. inner core
Quiz Time! 1. The plates move along the top of the A. core B. asthenosphere C. crust D. inner core
Quiz Time! 2. Plate movement occurs because of A. conduction currents in the mantle B. convection currents in the mantle C. convection currents in the crust D. conduction currents in the crust
Quiz Time! 2. Plate movement occurs because of A. conduction currents in the mantle B. convection currents in the mantle C. convection currents in the crust D. conduction currents in the crust
Quiz Time! 3. Earth’s lithosphere is broken into a number of large pieces called… A. faults B. volcanoes C. plates D. folds
Quiz Time! 3. Earth’s lithosphere is broken into a number of large pieces called… A. faults B. volcanoes C. plates D. folds
3 Types of Stress tension compression shearing a force that acts on a rock to change its shape or volume tension compression shearing
three types of plate boundaries! Now let’s move on to the three types of plate boundaries!
Convergent Plate Boundary Plate Boundaries Convergent Plate Boundary two plates moving towards each other stress = compression mountain building, trenches, volcanoes
Subduction Zone A convergent boundary where two tectonic plates collide. Oceanic crust is more dense and sinks beneath the continental crust. The Atlantic Ocean is getting larger as the Western Hemisphere moves away from Europe and Asia. The Pacific Ocean, on the other hand, is becoming smaller.
Subduction zones appear as deep oceanic trenches. Most of the continental mountain belts occur where plates are pressing against one another.
In the cross section of the Earth in the Southern Hemisphere, the map shows a subduction zone that has created the Peru-Chile Trench at the western edge of South American and the Andes Mountains along the west coast of South America.
CONVERGENT COLLIDE
Divergent Plate Boundary Plate Boundaries Divergent Plate Boundary two plates moving apart stress = tension
The Earth is producing “new” crust where two plates are diverging.
Mid-Atlantic Ridge The Atlantic Ocean is getting larger as the Western Hemisphere moves away from Europe and Asia while the Pacific Ocean is becoming smaller. This is occurring because the North and South American plates are moving westward.
Divergent Plate Boundary A satellite view of the Sinai Peninsula shows two arms of the Red Sea spreading ridge, exposed on land. This is the northern extension of Africa’s Great Rift Valley.
DIVERGENT DIVIDE
Transform Plate Boundary Plate Boundaries Transform Plate Boundary when two plates slide past one another stress = shearing
Meeting of the Plates An aerial view shows probably the most familiar meeting of two plates in the United States, the San Andreas fault slicing through the Carrizo Plain in the Temblor Range east of the city of San Luiz Obispo, CA. Photograph by Robert E. Wallace, USGS
EARTHQUAKES!!!
TRANSFORM TECTONIC PLATES SLIDE
Why do volcanoes occur? magma rises to the surface where the earth’s plates pull apart (divergent zones) “holes” in the plates called hotspots cooler oceanic crust dives underneath continental crust (subduction boundary) forcing magma to rise to the surface
Where do volcanoes occur? mostly where plates meet middle of tectonic plates at hotspots A lot of volcanoes occur around the edge of the pacific ocean called the Pacific Ring of Fire.
Trench Forms When the less dense, lighter continental plate overrides the oceanic plate a subduction zone forms.
TRANSFORM TECTONIC PLATES, SLIDE DIVERGENT, DIVIDE CONVERGENT, COLLIDE TRANSFORM TECTONIC PLATES, SLIDE
Quiz Time! 4. Plate boundary where new crust is being formed A. convergent B. divergent C. transform
Quiz Time! 4. Plate boundary where new crust is being formed A. convergent B. divergent C. transform
Quiz Time! 5. Two plates sliding next to each other A. convergent B. divergent C. transform
Quiz Time! 5. Two plates sliding next to each other A. convergent B. divergent C. transform
Quiz Time! 6. Where mountain building occurs A. convergent B. divergent C. transform
Quiz Time! 6. Where mountain building occurs A. convergent B. divergent C. transform
Quiz Time! 7. A. shearing B. tension C. compression
Quiz Time! 7. A. shearing B. tension C. compression
Quiz Time! 8. A. shearing B. tension C. compression
Quiz Time! 8. A. shearing B. tension C. compression
Quiz Time! 9. A. shearing B. tension C. compression
Quiz Time! 9. A. shearing B. tension C. compression
Quiz Time! 10. Subduction occurs at a A. transform plate boundary B. convergent plate boundary C. divergent plate boundary
Quiz Time! 10. Subduction occurs at a A. transform plate boundary B. convergent plate boundary C. divergent plate boundary
Plate Boundary Rap