As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading.
Sea floor magnetic pattern.
When the earth s magnetic field reverses a new stripe with the new polarity begins.
Samples collected from the ocean floor show that the age of oceanic crust increases with distance from the spreading centre important evidence in favour of this process.
Basalt the once molten rock that makes up most new oceanic crust is a fairly magnetic substance and scientists began using magnetometers to measure the magnetism of the ocean floor in the 1950s what they discovered was that the magnetism of the ocean floor around.
Understanding patterns of sea floor magnetism 30 points a magnetometer is an instrument used to measure very small variations in the magnetic intensity of the upper part of the earth s crust magnetometers can be moved around on land usually by a person on foot used in the air towed beneath an aircraft or used at sea towed behind a ship.
Plate tectonics plate tectonics seafloor spreading.
At slow spreading ridges the anomalies are squeezed tighter together but the basic.
These patterns of stripes provide the history of seafloor spreading.
These age data also allow the rate of seafloor spreading to be.
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.
Geophysicists can read these patterns from the magnetic anomalies they measure with a magnetometer.
Where the magnetic wiggles or anomalies are broader the spreading rate has been faster.