Plate Tectonics Web-Quest

http://www.learner.org/interactives/dynamicearth/structure/

 I: Earth’s Structure.
 Use the following link to find these answers:
http://www.learner.org/interactives/dynamicearth/structure.html

1. The lithosphere is made up of the ________ and a tiny bit of the _________ ___________
2. The plates of the lithosphere move (or float) on this hot, malleable __________ _________ zone in the upper mantle, directly underneath the lithosphere. This is known as the ___________________.
3. The layer of Earth that is the only liquid layer is the ___________ ___________.

 II. Plate Tectonics.
 Use the following link to find these answers: http://www.learner.org/interactives/dynamicearth/drift.html

1. What did Earth look like 250 million years ago?
 The continents of Earth were clustered together in formation that a scientist named _____________. The scientist that named “Pangaea” was a German scientist by the name of ____________________  He theorized that “Pangaea" split apart and the different landmasses, or continents, drifted to their current locations on the globe. Wegener’s theories of plate movement became the basis for the development of the theory of ____________ ________________

2. The place where the two plates meet is called a ____________________. Boundaries have different names depending on how the two plates are moving in relationship to each other.
A. If two plates are pushing towards each other it is called a _______________________.
B. If two plates are moving apart from each other it is called a ______________________.
C. If two plates are sliding past each other it is a called a __________________________

 IV. Slip, Slide, and Collide.
 Use the following link to find these answers: http://www.learner.org/interactives/dynamicearth/slip.html

1. At convergent boundaries, tectonic plates ___________ with each other. The events that occur at these boundaries are linked to the types of plates (oceanic or _______________) that are interacting. Subduction Zones and Volcanoes At some convergent boundaries, an oceanic plate collides with a continental plate. Oceanic crust tends to be ____________ and _____________ than continental crust, so the denser oceanic crust gets bent and pulled under, or ________________, beneath the lighter and thicker continental crust. This forms what is called a subduction zone. As the oceanic crust sinks, a deep oceanic ____________, or valley, is formed at the edge of the continent. The crust continues to be forced deeper into the earth, where high heat and pressure cause trapped water and other gasses to be released from it. This, in turn, makes the base of the crust melt, forming ___________. The magma formed at a subduction zone rises up toward the earth's surface and builds up in magma chambers, where it feeds and creates ________________ on the overriding plate. When this magma finds its way to ____ the surface through a vent in the crust, the volcano erupts, expelling ___________ and __________. An example of this is the band of active volcanoes that encircle the Pacific Ocean, often referred to as the Ring of Fire.

A subduction zone is also generated when two oceanic plates collide — the older plate is forced under the ______________ one, and it leads to the formation of chains of volcanic islands known as ____________ ___________.

Collision Zones and Mountains

What happens when two continental plates collide?
 Because the rock making up continental plates is generally lighter and less dense than oceanic rock, it is too light to get pulled under the earth and turned into magma. Instead, a collision between two continental plates crunches and folds the rock at the boundary, lifting it up and leading to the formation of __________________ .


2. At divergent boundaries, tectonic plates are moving __________ from each other. One result of huge masses of crust moving apart is ______________ spreading. This occurs when two plates made of oceanic crust pull apart. A crack in the ocean floor appears and then magma oozes up from the mantle to fill in the space between the plates, forming a raised ridge called a _______________ ___________. The magma also spreads outward, forming _________ ocean floor and _________ oceanic crust. When two _______________ plates diverge, a valley-like rift develops. This __________ is a dropped zone where the plates are pulling apart. As the crust widens and thins, valleys form in and around the area, as do _______________, which may become increasingly active. Early in the rift formation, streams and rivers flow into the low valleys and long, narrow lakes can be created. Eventually, the widening crust along the divergent boundary may become thin enough that a piece of the continent breaks off, forming a new tectonic plate.

3. At transform boundaries, tectonic plates are not moving directly toward or directly away from each other. Instead, two tectonic plates ___________ past each other in a horizontal direction. This kind of boundary results in a _________. A fault is a crack or ___________ in the earth's crust that is associated with this movement. Transform boundaries and the resulting faults produce many ________________ because edges of tectonic plates are jagged rather than ____________. As the plates grind past each other, the jagged edges strike each other, catch, and stick, "locking" the plates in place for a time. Because the plates are locked together without moving, a lot of ____________ builds up at the fault line. This stress is released in quick bursts when the plates suddenly slip into new positions. The sudden movement is what we feel as the shaking and trembling of an earthquake. The motion of the plates at a transform boundary has given this type of fault another name, a _________________ ____________. The best-studied strike-slip fault is the San Andreas Fault in _____