When magma flows out of a mid ocean ridge small magnetic minerals in the magma align themselves to point in the direction of the earth s current magnetic north.
Magnetic minerals on the ocean floor.
Scientists can use this data to make magnetic maps of the ocean floor.
Basalt is one of these rocks.
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.
Magnetic striping magnetic minerals are found in rocks.
Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.
Magnetic striping of the sea floor after mid ocean ridges and trenches were discovered more evidence was discovered that helped to support the theory that the continents had moved around.
3 rocks containing iron give us a record of earth s magnetic field.
These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.
It is found in lava.
Evidence for seafloor spreading.
From studies of the magnetic properties and the ages of igneous rocks on the ocean floor.
Magnetic reversalssome of the most important evidence of seafloor spreading comes from magnetic reversals recorded in the ocean floor.
As lava cools the minerals settle parallel to the earth s magnetic field.
These minerals provide a record of the direction of earth s magnetic field at the time when the molten matter that formed the rock.
When the earth s magnetic field reverses a new stripe with the new polarity begins.
Throughout earth s history.
Plate tectonics explains patterns observed in data from these studies.