Seafloor Secrets
This is the relationship between the age of seafloor rock and its distance from a ridge.
What is "rock age increases as distance increases"?
This is the semiliquid layer of the Earth that tectonic plates float on.
What is the asthenosphere?
This is the type of boundary where two plates pull away from each other.
What is a divergent plate boundary?
These are the two different types of magnetic "directions" found in seafloor stripes.
What are Normal and Reversed polarity?
This is the scientific theory that explains how Earth's surface is broken into moving pieces.
What is Plate Tectonics?
Wider bands of oceanic crust suggest this about the rate of seafloor spreading, when compared to places with thinner bands.
What is faster seafloor spreading?
This "circular" process in the mantle acts like a conveyor belt to move the plates above.
What is mantle convection?
This process happens when an oceanic plate slides underneath a continental plate.
What is subduction?
Magnetic stripes are symmetrical, meaning they look like this on both sides of a ridge.
What is a mirror image (or identical)?
Finding the same land reptile fossil on two different continents is evidence that they once did this.
What is "they were once joined"?
This substance erupts through the mid-ocean ridge and then hardens to form new ocean floor.
What is molten material? (What is magma?)
When magma cools quickly in cold ocean water at a ridge, it forms these "cushiony" shapes, proving new material is being added to the ocean floor.
What is pillow lava?
This geological feature is created when two oceanic plates collide together.
What are island arcs?
This is the metal in volcanic rock that orients itself towards the magnetic pole.
What is iron?
Even though new crust is always being made, Earth doesn't grow bigger because of this recycling process.
What is subduction?
This is the main reason why there is very little oceanic crust older than 340 million years.
What is subduction (or recycling into the mantle)?
Magma rises to the surface and adds new material to the seafloor at this specific location.
What is a mid ocean ridge?
When two continental plates converge (crash into each other), they push upward to form these.
What are mountain ranges?
Seafloor rocks lock in magnetic data at the exact moment the magma does this.
What is solidifies?
This is the name for the deep valley formed where a subducting plate begins to sink.
What is a trench?
Mapping the age of this layer allows scientists to reconstruct millions of years of Earth's surface history.
What is the lithosphere? (oceanic)
This is what happens to the size of an ocean basin when new magma is added to the seafloor.
What is "the basin gets larger"?
When two plates converge, the oceanic plate always subducts into the mantle for this reason.
What is "it is denser than the continental crust”?
This phenomenon causes the "stripes" to differ in polarity rather than all being identical.
What is the reversal of Earth's magnetic field?
This country is unique because the Mid-Atlantic Ridge rises above sea level here. (Zac Efron went here)
What is Iceland?