New oceanic crust is being created at the mid-ocean rift zones, a global divergent plate boundary system where uprising magma fills in the spaces being created by the pulling apart of plates. Part of the newly forming crust follows the direction of one plate, and part of the newly forming crust follows the direction of the other plate; therefore, the age of the rock created from the magma has a mirror image on either side of the rift.
As new oceanic crust is continuously being formed at the mid-ocean ridges by upwelling molten rock, the direction of Earth's magnetic field is recorded in the rock by the orientation of magnetic minerals, which align themselves in the direction of the magnetic field before the rock completely crystallizes.
Earth's magnetic field is known to change its orientation with frequency on a geologic time scale, thus a pattern of stripes of magnetic orientation is formed which can be detected with a magnetometer.
The discovery of magnetic stripes on the seafloor have allowed researchers to provide additional proof that new crust is being created, and that magnetic reversals have occurred and will occur in the future.
They tell us that over the course of thousands of years, Earth's polarity will reverse itself. The stripes are the magnetic "footprint" of Earth's shifting magnetic field.
provide evidence for sea-floor spreading
Spreading Of ocean floor
Mapping of magnetic anomalies on the ocean floor shows alternating bands of normal and reversed polarity, indicating that new oceanic crust is continuously forming at mid-ocean ridges and spreading away in opposite directions.
Strips of ocean-floor basalt record the polarity of earth's magnetic field at the time the rock formed. These strips form a pattern that is the same on both sides of the mid-ocean ridge. the pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.
Scientists found evidence of magnetic stripes on the ocean floor, which indicated periodic reversals in Earth's magnetic field. This discovery helped support the theory of plate tectonics and seafloor spreading.
Magnetic minerals on the ocean floor.
True. Bands of magnetic material in the sea floor that have opposite poles or exhibit magnetic reversal provide evidence for sea floor spreading. This is because as new oceanic crust forms at mid-ocean ridges, Earth's magnetic field periodically reverses, creating magnetic stripes on the ocean floor that align with the direction of the magnetic field at that time.
Magnetic striping on the ocean floor is used as evidence for seafloor spreading. As new oceanic crust forms at mid-ocean ridges, Earth's magnetic field is recorded in the rocks in alternating patterns of normal and reversed polarity. This provides support for the idea that new crust is continuously being created at mid-ocean ridges and spreading away in opposite directions.
sea floor-spreading..;)
Scientists found Alternating bands of magnetism.
That magnetic minerals spreading from a mid-ocean ridge
That magnetic minerals spreading from a mid-ocean ridge
That magnetic minerals spreading from a mid-ocean ridge
provide evidence for sea-floor spreading
Spreading Of ocean floor
The discovery of mid-ocean ridges, where new oceanic crust is formed, supported the theory of sea-floor spreading. The mapping of magnetic stripes on the ocean floor, showing alternating patterns of magnetic polarity, provided further evidence for sea-floor spreading. The age of the oceanic crust getting progressively younger away from the mid-ocean ridges supported the concept of sea-floor spreading.
Strips of ocean-floor basalt record the polarity of earth's magnetic field at the time the rock formed. These strips form a pattern that is the same on both sides of the mid-ocean ridge. the pattern shows that ocean floor forms along mid-ocean ridges and then moves away from the ridge.