What is the force that causes the seafloor to spread and continents to drift?
Thermal convection Plate Tectonics
What is the primary source that causes the seafloor to spread?
Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churning motion of Earth’s mantle. Convection currents carry heat from the lower mantle and core to the lithosphere.
What is the force that may cause the shifting of the continents?
It’s All About the Plates Heat from the Earth’s interior causes this motion to happen via convection currents in the mantle. Over a period of millions of years, this slow motion caused the single supercontinent to split into the seven continents you see today.
Why is the earth not getting bigger despite the fact that?
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.
Which magnetic stripe is the oldest How do you know?
The north pole becomes the south pole, and the south pole becomes the north pole. Rocks of normal and reversed polarity are found in stripes symmetrically about the mid-ocean ridge axis. The seafloor is youngest at the ridge crest and oldest far away from the ridge crest.
What is the pattern seen in the ages of the seafloor?
What do you notice about the age pattern on the seafloor in the Atlantic Ocean (hint: look on each side of the middle)? The age pattern is symmetric. Youngest ages are at the middle of the pattern (on the oceanic ridges) and the seafloor grows older moving outwards to each side of the middle.
What do the magnetic stripes pattern represents?
Scientists discovered that the rock that makes up the ocean floor lies in a pattern of magnetized “stripes.” These stripes hold a record of reversals in Earth’s magnetic field. The rock of the ocean floor contains iron. The rock began as molten material that cooled and hardened.
How did drilling samples show that sea floor spreading really has taken place?
Evidence From Drilling Samples The final proof of sea-floor spreading came from rock samples obtained by drilling into the ocean floor. They found that the farther away from the ridge the samples were taken, the older the rocks were. The youngest rocks were always in the center of the ridges.