Hot magma forced upward at mid-ocean ridges produces sea _______.
100
Asthenosphere
plasticlike layer of Eath's surface below the lithosphere?
100
A current in a fluid that results from convection
Convection Current
200
Drift
The hypothesis that continents move slowly is called continental____.
200
In the Atlantic, the Pacific and in other oceans
How were mid-ocean ridges discovered?
200
Plate Tectonics
theory that states that Earth's crust and upper mantle are broken into sections, which move around on a special layer of the mantle?
200
The rigid outer part of the earth, consisting of the crust and upper mantle
Lithosphere
300
Pangaea
All continents once might have been connected in a large landmass called ______.
300
As the seafloor spreads apart, magma moves upward and flows from the cracks, it becomes solid as it cools.
How does new seafloor form at mid-ocean ridges?
300
Subduction Zone
Area where an oceanic plate goes down into the mantle?
300
The upper layer of the Earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur
Asthenosphere
400
Alfred Wegener
Who proposed continental drift?
400
It moves away from the ridge in opposite directions.
Where is the older seafloor?
400
Transform boundary
Plate boundary that occurs when two plates slide past one another?
400
A supercontinent comprising all the continental crust of the Earth, postulated to have existed in late Paleozoic and Mesozoic times before it broke into Gondwana and Laurasia
Pangaea
500
Spreading
Hot magma forced upward at mid-ocean ridges produces seafloor ________.
500
Magnetometer
Sensing device that detects magnetic fields, helping to confirm seafloor spreading.
500
Convergent boundary
Place where two plates move together?
500
A theory explaining the structure of the Earth's crust and many associated phenomena as resulting from the interaction of rigid lithosphere plates that move slowly over the underlying mantle