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