PTR - Plate Tectonics and Rock Cycle Module Overview

 

Plate Tectonics and Rock Cycle

Although the Earth's surface may seem to be singular, static, and motionless, it is actually a dynamic, segmented layer that is continually under stress and in motion. These stresses are caused by the motion of convection currents underneath the crust, and result in some of the most spectacular and devastating landforms and events that have been witnessed by man, including mountains, rift valleys, volcanoes and earthquakes. This module examines how the Earth's surface is actually constructed, how the pieces move, and the resultant landforms that characterize interactions between each piece.

Essential Questions:

• How can we compare and contrast the different types of plate tectonic settings (convergent, divergent, and transform boundaries), including subduction zones, continental collisions, rift zones, and ocean basins?
• How do various plate tectonic settings contribute to the formation of major geologic features, landforms, Earth materials, and geologic hazards?
• Which plate tectonic setting(s) and transformation process(es) can be attributed to the formation of sedimentary, igneous, and metamorphic rock types?

Key Words:

1. Caldera - a depression created after a volcano releases the majority of the contents of its magma chamber in an explosive eruption
2. Cinder Cone Volcano - a steep, conical hill consisting of glassy volcanic fragments that accumulate around and downwind from a volcanic vent
3. Composite Volcano - a conical volcano built up by many layers (strata) of hardened lava, tephra, pumice, and volcanic ash
4. Conduction - the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material
5. Convection - the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat
6. Convergent Boundary - an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide
7. Divergent Boundary - a tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates
8. Fault - a break in the rocks that make up the Earth's crust, along which rocks on either side have moved past each other
9. Footwall - the side of a fault that protrudes farther at the bottom than the top of the fault
10. Hanging Wall - the side of a fault that protrudes farther at the top than the bottom of the fault
11. Heat - the transfer of thermal energy from one medium or object to another, or from an energy source to a medium or object
12. Hot Spot - the theory that abnormally hot, stationary region areas of the mantle cause the lithosphere to melt as the plate is moved over the area, forming chains of volcanic islands
13. Igneous Rock - rocks that are formed from the solidification of molten rock material
14. Lava - the molten rock expelled by a volcano during an eruption. The resulting rock after solidification and cooling is also called lava
15. Magma - molten rock usually located deep within the mantle of the Earth that occasionally comes to the surface through cracks in the mantle or through the eruption of volcanoes
16. Metamorphic Rock - rocks that have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture, and chemical composition of the rocks
17. Minerals - naturally occurring, inorganic solids that have a specific chemical composition and a crystalline structure
18. Normal Fault - a geologic fault in which the hanging wall has moved downward relative to the footwall. Normal faults occur where two blocks of rock are pulled apart, as by tension
19. Ocean Basin - The large depressions in the Earth's crust that underly the oceans. All of the ocean basins were formed from volcanic rock that was released from fissures located at the mid-oceanic ridges. The oldest rocks found in these basins are approximately 200 million years old
20. Reverse Fault - a geologic fault in which the hanging wall has moved upward relative to the footwall. Reverse faults occur where two blocks of rock are forced together by compression
21. Rift Zone - a large area of the earth in which plates of the earth's crust are moving away from each other, forming an extensive system of fractures and faults
22. Rock - any coherent, naturally occurring substance generally composed of minerals
23. Sedimentary Rock - rock that has formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice (glaciers), and wind
24. Shield Volcano - a type of volcano usually built almost entirely of fluid lava flows. It is named for its low profile, resembling a warrior's shield lying on the ground
25. Strike Slip Fault - vertical (or nearly vertical) fractures where the blocks have mostly moved horizontally. If the block opposite an observer looking across the fault moves to the right, the slip style is termed right lateral; if the block moves to the left, the motion is termed left lateral
26. Subduction Zone - the place where two lithospheric plates come together, one riding over the other. Most volcanoes on land occur parallel to and inland from the boundary between the two plates
27. Tectonic Plate - a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere
28. Transform Boundary - locations where two plates slide past one another

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