- What does seafloor spreading look like?
- What type of rock is oceanic crust generally made of?
- What happens as the seafloor spreads apart?
- What are the three pieces of evidence for seafloor spreading?
- What do Earth’s magnetic stripes indicate about oceanic crust?
- Is Earth’s polarity normal or reversed?
- How long will Earth’s magnetic field last?
- What happens if magnetic pole flips?
- What are the steps in seafloor spreading?
- Why is the ocean floor not flat?
- What is the importance of seafloor spreading in understanding the origin of the plate?
- What causes the zebra pattern on the ocean floor?
- What happens if Earth’s magnetic field flips?
- How do magnetic stripes on the ocean floor serve as evidence for seafloor spreading quizlet?
- What evidence supports the theory of ocean floor?
What does seafloor spreading look like?
Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.
Seafloor spreading and other tectonic activity processes are the result of mantle convection.
The less-dense material rises, often forming a mountain or elevated area of the seafloor..
What type of rock is oceanic crust generally made of?
basaltOceanic crust is generally composed of dark-colored rocks called basalt and gabbro. It is thinner and denser than continental crust, which is made of light-colored rocks called andesite and granite. The low density of continental crust causes it to “float” high atop the viscous mantle, forming dry land.
What happens as the seafloor spreads apart?
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.
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.
What do Earth’s magnetic stripes indicate about oceanic crust?
These surveys revealed a series of invisible magnetic “stripes” of normal and reversed polarity in the sea floor, like that shown in the figure below. The patterns reflect the creation and spreading of oceanic crust along the mid-oceanic ridges. Basalt forming at the ridge crest picks up the existing magnetic polarity.
Is Earth’s polarity normal or reversed?
We know that the Earth’s poles have reversed hundreds of times. It’s a dynamic system inside the outer core and it has to reverse at times because that’s just part of the way it works. We know it’s done this most recently 780,000 years ago, so there are people who say it’s overdue.
How long will Earth’s magnetic field last?
Over the last two centuries the dipole strength has been decreasing at a rate of about 6.3% per century. At this rate of decrease, the field would be negligible in about 1600 years. However, this strength is about average for the last 7 thousand years, and the current rate of change is not unusual.
What happens if magnetic pole flips?
This is what has happened when the magnetic poles flipped in the past. … This could weaken Earth’s protective magnetic field by up to 90% during a polar flip. Earth’s magnetic field is what shields us from harmful space radiation which can damage cells, cause cancer, and fry electronic circuits and electrical grids.
What are the steps in seafloor spreading?
What are the steps in the process of sea floor 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.
Why is the ocean floor not flat?
The difference is sea level is caused by two major factors: tides and ocean currents. Tides are mainly caused by the gravitational pull of the Moon and the Sun, acting on the Earth’s surface. Ocean currents are caused by winds and a mixing of waters with different densities.
What is the importance of seafloor spreading in understanding the origin of the plate?
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.
What causes the zebra pattern on the ocean floor?
What has caused the “zebra” pattern in the rock of the ocean floor? … Rocks makes up the seafloor has iron in it and as the mid ocean ridge cools little pieces of iron “line up” with Earth’s magnetic field and then they stay like the magnetic field is preserved and the seafloor spread.
What happens if Earth’s magnetic field flips?
During an excursion or a reversal, the magnetic field is considerably weakened and allows many more cosmic rays to reach the surface of the planet. These energetic particles from space can be damaging to life on Earth if too many reach the surface.
How do magnetic stripes on the ocean floor serve as evidence for seafloor spreading quizlet?
How do strips of magnetized rock on the ocean floor provide evidence of sea-floor spreading? Strips of ocean-floor basalt record the polarity of Earth’s magnetic field at the time the rock formed. … The pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.
What evidence supports the theory of ocean floor?
Several types of evidence supported Hess’s 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. This evidence led scientists to look again at Wegener’s hypothesis of continental drift.