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 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.
How can the seafloor spread?
Volcanic activity
causes the seafloor to spread along oceanic ridges, forming new areas of crust and mantle. … This contraction can trigger oceanic earthquakes. The basic mechanics of tectonic plates—the massive, constantly shifting puzzle pieces that make up the Earth’s surface—are fairly well understood.
What causes the formation of new seafloor?
Explanation: Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through
volcanic activity
and then gradually moves away from the ridge.At a spreading center, basaltic magma rises up the fractures and cools on the ocean floor to form new seabed.
What was the main evidence for sea floor spreading?
The theory of seafloor spreading states that new ocean crust is continually being formed, and that this crust is slowly carried away from its point of origin over a period of time.
The study of the repeated reversal of the Earth’s magnetic poles over time
has provided convincing evidence of seafloor spreading.
What is the first step of seafloor spreading?
1.
A long crack in the oceanic crust forms at a mid ocean ridge
. 2. Molten material rises and erupts along the ridge.
What are different types of seafloor spreading?
There are three types of plate-plate interactions based upon relative motion: convergent, where plates collide,
divergent
, where plates separate, and transform motion, where plates simply slide past each other.
What is the root cause of 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 the three pieces of evidence for seafloor spreading?
What three types of evidence provided support for the theory of sea floor spreading?
eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves.
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 are two pieces of evidence for 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
. This evidence also led sci- entists to look again at Wegener’s theory of continental drift.
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.
Why is Earth not growing in spite of seafloor spreading?
New crust is continually being pushed away from divergent boundaries (where sea-floor spreading occurs), increasing Earth’s surface. But the
Earth isn’t getting any bigger
. … Deep below the Earth’s surface, subduction causes partial melting of both the ocean crust and mantle as they slide past one another.
What are 4 pieces of evidence for 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
.
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
.
Who proved that the seafloor is spreading?
The seafloor spreading hypothesis was proposed by the
American geophysicist Harry H. Hess
in 1960.
