How does the seafloor spreading related to magnetic reversal?
When the Earth’s magnetic field reverses, a new stripe, with the new polarity, begins. Such magnetic patterns led to recognition of the occurrence of sea-floor spreading, and they remain some of the strongest evidence for the theory of plate tectonics. The figure below includes two images of the ocean floor.
How does the seafloor become magnetized?
Seafloor spreading – The seafloor is characterized by mid-ocean ridges. When lava is extruded at any mid-ocean ridge, the rock it forms becomes magnetized and acquires the magnetic polarity that exists at the time the lava cools.
What happens when the seafloor spreads?
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 does seafloor magnetism at an Ocean Ridge prove?
Seafloor Magnetism Shipboard magnetometers reveal the magnetic polarity of the rock beneath them. When scientists plotted the points of normal and reversed polarity on a seafloor map they made an astonishing discovery: the normal and reversed magnetic polarity of seafloor basalts creates a pattern.
Is the magnetic stripe pattern on each side of the ocean ridge equal?
When lava gets erupted at the mid-ocean ridge axis it cools and turns into hard rock. As it cools it becomes permanently magnetized in the direction of the Earth’s magnetic field. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid-ocean ridges.
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.
How were scientists able to determine the date of the magnetic reversals during seafloor spreading?
How were scientists able to determine the date of the magnetic reversals during seafloor spreading? A record of Earth’s magnetic field is recorded in oceanic rocks, which show a clear pattern of changes in Earth’s magnetic polarity.
What does the magnetic stripes pattern represent?
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.
Why is it important that your model have an identical pattern of stripes on both sides of the center slit?
Why is it important that your model have an identical pattern of strips on both sides of the center slit? The model has identical strips because, as the magma rises at the mid ocean ridge ½ goes to the right and ½ goes to the left of the mid ocean ridge. Each one of these strips represents Earth’s magnetic history.
What does this tell you about the lengths of time represented by normal and reversed polarity?
Answer. If we know the absolute ages of rocks on either side of a reversal (normal to reversed, or reversed to normal), then we know that the time of the reversal must have been between the known dates. In this way, scientists have assigned ages to the magnetic anomaly pattern seen around the world.
What is the process of magnetic reversal?
By magnetic reversal, or ‘flip’, we mean the process by which the North pole is transformed into a South pole and the South pole becomes a North pole. Interestingly, the magnetic field may sometimes only undergo an ‘excursion’, rather than a reversal.
What is the cause of magnetic reversal?
The rotation of the Earth causes the buoyant fluid to rise in curved trajectories, which generate new magnetic field by twisting and shearing the existing magnetic field. Occasionally, however, the dipole part of the field reverses, causing the locations of the north and south magnetic poles to switch.
What happens during a geomagnetic reversal?
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.
What will be badly affected by polar reversal?
But the reality is that: Multiple magnetic fields would fight each other. 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 caused Mars to lose its magnetic field?
For years, scientists believed that this field disappeared over 4 billion years ago, causing Mars’ atmosphere to be slowly stripped away by solar wind. Like Earth, Mars global magnetic field is believed to have been the result of a dynamo effect caused by action in its core.
Why is Earth’s magnetic field so weak?
The forces in the core and the tilt of the magnetic axis together produce the anomaly, the area of weaker magnetism – allowing charged particles trapped in Earth’s magnetic field to dip closer to the surface.
What will happen if the size of the Earth is two times bigger than its original size?
If Earth’s diameter were doubled to about 16,000 miles, the planet’s mass would increase eight times, and the force of gravity on the planet would be twice as strong. If gravity were twice as strong , bodies possessing the same construction and mass as our flora and fauna would weigh twice as much and would collapse.
What is the only planet that contains life?
Is there life on Venus?
Although there is little possibility of existing life near the surface of Venus, the altitudes about 50 km (31 mi) above the surface have a mild temperature, and hence there are still some opinions in favor of such a possibility in the atmosphere of Venus.