The Theory of Plate Tectonics
• Earth’s crust is made of many ________• These plates move as a result of
______________ in the mantle• Earth’s surface is constantly being
_____________by these movements• Earthquakes, volcanoes, rifting and
mountain building all result from the process of ________________.
“ Continental Drift”
• ________________– German scientist
• Continents have not always been in their present locations
• All continents were once part of a __________ - ________ called _________
• Also only one great ocean called ______________
EVIDENCE TO SUPPORT CONTINENTAL DRIFT
• Puzzle-Like fit of the continents
• Fossil Evidence
• Matching Geologic Features
• Evidence of Climate Change
___________________
The Movement of ________
CONVECTION
• Convection is ___________ motion and the transfer of heat resulting from heating and __________ differences
• Lithospheric plates move as a result of ____________ in the mantle
• Convections cells in the ______________ rotate slowly over millions of years.
• Because the convections cells rotate in different directions, the ____________ move in different directions also
Plate _______________
• Where two plates _______ a plate boundary is formed.
• What happens at a plate boundary depends on the _________ each plate is moving and the density of each plate
• Earth’s surface is constantly being __________ by these movements
• Earthquakes, volcanoes, rifting and __________ _________ occur at or near plate boundaries.
• Plate movements also cause ________ that affect areas along the boundary and within the ___________itself.
Type of Plate Boundaries
• Plate boundaries are classified into three main groups based upon the relative _____________ of movement– ______________ Plate Boundary: plate move
towards each other– _____________ Plate Boundary: plate move
apart– ______________ Boundaries: plate slide past
each other (side by side)
Convergent Boundaries
• There are three types of convergent boundaries classified the type of crust involved:– Continent to continent convergence– Ocean to continent convergence– Ocean to ocean convergence
The Himalayan Mountains, Including Mt. Everest, formed as a result of the convergence of the Indian and Asian Plates
__________________________
Island arc volcanoes and deep ocean trenches form at ocean crust to ocean crust convergent boundaries
_________ - _______ boundaries:
Ocean crust to continental crust convergent boundary. Because oceanic crust is more dense than continental crust, the ocean crust is subducted
__________ - ________ boundaries:
_____________ Zones
• When two plates of different __________ collide at a convergent boundary, the denser plate is driven _______ the less dense _______ forming a subduction zone
• ________ is generated in the subduction zone resulting in the formation of volcanic arcs.
Transform Boundaries
• When two plates _____ past each other a _________ boundary is formed.
• Earthquakes are _________ along transform boundaries because the plates do not slide __________ past each other
The San Andreas fault is an example of a Transform Boundary
__________ Boundaries
• When two plates move apart a _________ boundary is formed.
• Mid-Ocean Ridges and ____ ______form at __________ boundaries
New ocean crust is created at mid-ocean ridges.
These are also referred to as spreading centers
Iceland is a volcanic island that has formed on top of a Mid- Atlantic ridge