Several types of evidence supported hess s theory of sea floor spreading.
Magnetic stripes in the ocean floor.
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.
These patterns were unlike any seen for continental 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.
Over time the earth s magnetic field reverses its north.
One stripe with normal polarity and the adjoining stripe with reversed polarity.
Identify the factors that cause magnetic stripes to form along the ocean floor.
This evidence led scientists to look again at wegener s hypothesis of continental drift.
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.
When the earth s magnetic field reverses a new stripe with the new polarity begins.
These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.
Magnetic evidence for seafloor spreading explains how magnetic polarity frozen into seafloor basalts reveals evidence for the creation of new seafloor at mid ocean ridges.
Magnetic direction of rock changes as earth s magnetic poles drift.
Magnetic striping magnetic minerals are found in rocks.
Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves.
Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor.
Evidence from molten material.
Magma acquires the magnetic direction present on earth when it hardens into rock 3.
Magnetic stripes on the ocean floor are hallmarks of seafloor spreading but have now been found on the ground in ethiopia where crust is pulling apart.
Plates move as new rock forms which causes magnetic direction to skew away.
The figure below includes two images of the ocean floor.
Among the new findings was the discovery of zebra stripe like magnetic patterns for the rocks of the ocean floor.
Evidence for sea floor spreading.
When these magnetic patterns were mapped over a wide region the ocean floor showed a zebra like pattern.
In the 20th century the magnetic survey was conducted in the mid ocean ridge in order to investigate evidence of sea floor spreading.
Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.