Rocks lock in their magnetism when they cool.
Rocks lock in their magnetism when they cool
rocks get older as you move away from ocean ridges
Magnetic stripes can be seen as you move away from ocean ridges.
Iron gains magnetism at a certain temperature known as the curie point. at this point Iron rich minerals align with the magnetic polls. Today Iron minerals have been found in older rocks pointing in a variety of directions and since our polls do not move this provided evidence that the Continents containing those minerals have moved and after lining up these magnetic rocks with others from the same time they all correlate with Continental drift and plate tech-tonics.
It determines how far the ocean has spread
The presence of magnetic domains of alternating orientation parallel to the plate boundaries.
rocks get older as you move away from ocean ridges
Rocks lock in their magnetism when they cool.
type your anwser here
Because of the stripes at the sea floor which are magnetic minerals
Because of the stripes at the sea floor which are magnetic minerals
The presence of magnetic domains of alternating orientation parallel to the plate boundaries.
They technically don't. They do provide evidence for it, however, in that they occur in pairs on either side of a rift, providing strong evidence that the rocks on either side were deposited at the same time and that the rifts are spreading.
Magnetic stripes can be seen as you move away from ocean ridges.
tits
Not really but sea floor sediments thickness increase with increased distance from spreading centers which is good evidence. Other evidence such as magnetic reversals, temperature, dating methods provide the best evidence of seafloor spreading
Magnetic reversals found in the sea floor do not cause continental drift. It does however provide evidence that sea floor spreading occurs (and hence is evidence for the theory of plate tectonics). This is because the iron rich minerals in basaltic rocks (such as magnetite) are at high temperatures when they are first intruded into the crust and at these high temperatures they record the orientation of Earth's magnetic field. As they cool, this record of the orientation of the magnetic field is "locked" in place. The Earth's magnetic field is known to "reverse polarity" - the north and south magnetic poles switch over time and so the orientation of the magnetic field in newly cooled rocks will change to match this. Geophysicists had recognised that there were alternating bands of rocks with these reversed orientations of the magnetic field. These bands ran parallel to the Mid-Ocean-Ridges. In the 1960s after significant magnetic survey work was undertaken it was realised that the alternating bands on one side of the oceanic ridge were a mirror image to the bands on the other side. So why is this evidence for sea floor spreading / plate tectonics? Well it was realised that if the newly intruded rock was to move away from the Mid-Ocean-Ridge (M-O-R) and be replaced with new younger rock, this rock would continue to record the orientation of the Earth's magnetic field as and when reversals occurred. As such this would lead to the stripes of alternating magnetic orientation that are symmetrical about the M-O-R. As such movement of the plates away from a M-O-R and the reversals of Earth's magnetic field best explained the presence of these bands and so confirmed the idea that sea floor spreading was occurring. For more information, please see the related link.
Iron gains magnetism at a certain temperature known as the curie point. at this point Iron rich minerals align with the magnetic polls. Today Iron minerals have been found in older rocks pointing in a variety of directions and since our polls do not move this provided evidence that the Continents containing those minerals have moved and after lining up these magnetic rocks with others from the same time they all correlate with Continental drift and plate tech-tonics.