Plate Tectonics (ch.7-8) Flashcards
What was the theory of plate tectonics?
A continental drift hypothesis
Who wrote the theory of plates techtonics?
Alfred Wegner
What is Pangaea?
All seven of the continents combined into one supercontinent named Pangaea.
What evidence proved Pangaea once existed?
Rock clues
climate clues
fossil evidence
coastlines matching
What is seafloor spreading?
Magnetic reversals normal polarity reversal polarity
Define polarity
the direction of a magnetic or electric field.
What is a magnetic reversal?
a change in a planet’s magnetic field such that the positions of magnetic north and magnetic south are interchanged.
Define convection currents
a current in a fluid that results from convection.
Define subduction
the sideways and downward movement of the edge of a plate of the earth’s crust into the mantle beneath another plate.
What are the types of plate boundaries?
Convergent
divergent
transform
Defined by divergent plate boundary
two tectonic plates that are moving away from each other.
Define a convergent plate boundary
two tectonics plate boundaries move toward one another and collide.
Define transform plate boundary’s
A place where to tectonic plate slide past each other
What are the landforms at each plate boundary?
fold mountains
mid ocean ridges
ocean trenches
volcanos
Define fold mountains
mountains that form mainly by the effects of folding on layers within the upper part of the Earth’s crust.
Define volcano
A fissure within Earth’s crust which molten lava and gas erupts.
Defined mid Ocean Ridge
Any of various underwater mountain ranges forming a chain between divergent tectonic plates. Magma escapes from rifts along the tops of these ranges, adding new material to the earth’s crust.
Define a Ocean trench
A long narrow ditch
