How does sea-floor spreading occur?
A)New materials are being added to the asthenosphere
B) Earthquakes break apart the ocean floor
C)Sediments accumulate at the areas of the spreading
D)Molten material beneath Earth's crust rises to the surface
So is it D then?
Yes, D. The then rising molten magna cools, and spreads the existing plates away.
D
A
C
B
Glitch is correct
is it c
http://www.phschool.com/itext/sci_exp/ebook/products/0-13-181243-2/sx5055a3.gif
Yes, I think it's D. But check your text to be sure.
the answer is D :)
The correct answer is D) Molten material beneath Earth's crust rises to the surface.
Sea-floor spreading occurs primarily due to the movement of molten material, or magma, beneath Earth's crust. This process takes place at mid-ocean ridges, which are underwater mountain chains found in all major oceans. The mid-ocean ridges mark the boundaries between two tectonic plates, known as divergent boundaries.
Here's how sea-floor spreading occurs in more detail:
1. Heat from the Earth's core creates convection currents in the underlying mantle, causing the magma to rise towards the surface.
2. As the magma rises, it fills the gap created by the diverging tectonic plates at the mid-ocean ridge.
3. Once the magma reaches the seafloor, it cools and solidifies, forming new oceanic crust.
4. The newly formed crust pushes the existing crust away from the ridge, creating a spreading motion.
5. Over time, as more magma rises and new crust forms, the older crust moves further away from the ridge, spreading outwards.
6. As the older crust moves away, it undergoes cooling and becomes denser, eventually sinking back into the mantle at subduction zones.
Therefore, it is the continuous cycle of magma rising, solidifying, and pushing the older crust away that leads to sea-floor spreading.