What is the supercontinent that all continents were once part of?
Pangaea
Pangaea is the name given to the ancient supercontinent that existed during the late Paleozoic and early Mesozoic eras.
What are the three types of clues used to support the theory of continental drift?
- Rock Clues
- Fossil Clues
- Climate Clues
These clues provide evidence for the movement of continents over geological time.
Define seafloor spreading.
The process by which new oceanic crust forms along a mid-ocean ridge
Seafloor spreading is a key mechanism of plate tectonics.
What is the Mid-Ocean Ridge?
The mountain ranges in the middle of the oceans
Mid-ocean ridges are underwater mountain ranges formed by plate tectonics.
What is an echo sounder used for?
To determine the depth of the ocean floor
Echo sounders use sound waves to measure underwater depth.
What does a topographic map reveal?
Vast mountain ranges on the seafloor
Topographic maps provide detailed information about underwater terrain.
What are pillow lavas?
Lava that erupts into water and cools rapidly
Pillow lavas are typically formed at mid-ocean ridges.
Define abyssal plain.
Where sediment has built up far from the mid-ocean range
What is normal polarity?
A state in which magnetized objects will orient themselves to point north
Normal polarity is the typical orientation of Earth’s magnetic field.
What is magnetic reversal?
Magnetic field reverses direction
Magnetic reversals have occurred multiple times throughout Earth’s history.
Define reversed polarity.
A state in which magnetized objects would reverse direction and orient themselves to point south
Reversed polarity occurs during magnetic reversals.
What is the younger oceanic crust characterized by?
Sediment that is closest to the mid-ocean ridge
Older sediment is found farther away from the mid-ocean ridge.
What do magnetic stripes indicate?
Patterns of sediment age relative to the mid-ocean ridge
These stripes are evidence of seafloor spreading.
Define a transform plate boundary.
When two plates slide past each other
This movement can cause earthquakes.
What is the lithosphere?
The cold and rigid outermost rock layer
It includes the crust and the uppermost part of the mantle.
What is convection in geological terms?
The circulation of material caused by differences in temperature and density
This process is crucial for mantle dynamics.
Define a convergent plate boundary.
When two plates collide
This can lead to mountain formation or subduction.
What is slab pull?
When a slab sinks and pulls on the rest of the plate
This is a significant force in plate tectonics.
What does ridge push refer to?
Rising mantle material at mid-ocean ridges creating potential for plates to move away
This force contributes to seafloor spreading.
Define a divergent plate boundary.
When two plates separate
This is typically found at mid-ocean ridges.
What is basal drag?
Convection currents in the mantle
These currents can influence plate movement.
What does the theory of plate tectonics state?
The earth’s surface is made of rigid slabs of rock
These slabs are known as tectonic plates.
What is subduction?
The process in which a denser plate sinks below a more buoyant plate
This process is often associated with oceanic-continental convergence.
