The motivating force for seafloor spreading ridges is
tectonic plate slab pull at subduction zones
, rather than magma pressure, although there is typically significant magma activity at spreading ridges.
What are the 4 steps of seafloor spreading?
- Magma comes out of the rift valley.
- Magma cools to rock and hardens.
- Rock is pushed away as new rock is formed at MOR.
- Oceanic crust and continental crust meet at the trench.
- Oceanic crust bends down under the continental crust.
- Gravity pulls rock towards mantle.
- Rock melts to mantle.
What happens when the seafloor spreads?
Sea-floor spreading is what happens at the mid-oceanic ridge where
a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor
. As the plates move apart, new material wells up and cools onto the edge of the plates.
Where would seafloor spreading most likely occur quizlet?
Where does seafloor spreading occur? This process occurs along divergent plate boundaries at areas called
mid-ocean ridges
.
Who prove that seafloor is spreading?
This “recycling” process, later named “seafloor spreading,” carries off older sediment and fossils, and moves the continents as new ocean crust spreads away from the ridges. Supporting Wegener’s theory of continental drift,
Hess
explained how the once-joined continents had separated into the seven that exist today.
What is the importance of seafloor spreading?
Significance. Seafloor spreading
helps explain continental drift in the theory of plate tectonics
. When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere.
Why is seafloor spreading important?
Today it refers to the processes creating new oceanic lithosphere where plates move apart. Seafloor spreading
replaces the lithosphere destroyed by subduction
, and exerts important influences on Earth’s chemical and biological evolution.
What is the first step in seafloor spreading process?
1.
A long crack in the oceanic crust forms at a mid ocean ridge
. 2. Molten material rises and erupts along the ridge.
What is the first step in seafloor spreading?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks.
What are 2 pieces of evidence supporting seafloor spreading?
Harry Hess’s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. This evidence was from the investigations of
the molten material, seafloor drilling, radiometric age dating and fossil ages, and the magnetic stripes
.
What is one piece of evidence of seafloor spreading?
There is lots of evidence that proves that seafloor spreading is occurring. One piece of evidence is
mid-ocean ridges
. Rocks found near mid-ocean ridges are young and get older as the distance from the ocean ridge increases.
What are the three causes for plate motion?
Mantle dynamics, gravity, and Earth’s rotation taken
altogether causes the plate movements. However, convectional currents are the general thought for the motion.
What causes seafloor spreading quizlet?
During sea-floor spreading,
magma erupts along a mid-ocean ridge to form new oceanic
lithosphere. The floor then moves away from the ridge, often toward a trench at the edge of the ocean basin. … The pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.
What are 3 pieces of evidence that support seafloor spreading?
Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading-
evidence from molten material, magnetic stripes, and drilling samples
.
What are the features of seafloor?
Features of the ocean include
the continental shelf, slope, and rise
. The ocean floor is called the abyssal plain. Below the ocean floor, there are a few small deeper areas called ocean trenches. Features rising up from the ocean floor include seamounts, volcanic islands and the mid-oceanic ridges and rises.
Where is active seafloor spreading occurring today?
Where is active sea floor spreading occurring today? Seafloor spreading is the movement of old rock that is being pushed by the new young oceanic crust. This would be a divergent since the plates are separating from each other. Active seafloor spreading is occurring at
mid-ocean ridges
.
