sea-floor spreading
In what units are tectonic plate movements measured
centimeters a year
the boundary between two tectonic plates that are moving away from each other
divergent boundary
the hottest layer of the earth
inner core
what was Alfred Wegener's theory
that all continents were once all connected
The movement of a _________ plate and a ________ plate _________(toward, away from, sideways against ) each other forms mountain ranges.
Continental, continental, toward
Earthquakes usually begin at what part of a tectonic plate?
Fault
The layer of Earth below the athenosphere
Mantle
What was the name Wegner gave to his large single continent?
Pangaea
in sea-floor spreading how does new crust form
molten material comes up through the gap formed by the divergent boundary and hardens into new crust
What do you call movements of tectonic plates toward each other
Convergent
a place on earth's surface that is directly above a column of rising magma called a mantle plum
hot spot
the layer of the earth we walk on
crust/lithosphere
What woman cartographer finally showed Wegner's theory to be correct?
Marie Tharp
what is sea floor spreading
the process by which new oceanic lithosphere is created at mid-ocean ridges as older materials are pulled away from the ridge
what is divergent boundary
tectonic plates sliding past each other
why did scientist not accept Wegener's theory at first
they didnt think any force of nature could move entire continents
what are "pillow" lava
lava that comes through the crust and cools so rapidly that the inner rock is still molten after the outside cools
what is subduction zone
the region where an oceanic plate sinks down into the asthenosphere at a convergent boundary usually between continental and oceanic plates
a break in the earth's crust along which blocks of the crust slide relative to one another due to tectonic forces
fault
what evidence did Wegener have to prove his theory about Continental Drift
fossil evidence and the matching continent outlines when put together in their original arrangement