Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch.
Sea floor spreading age.
Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves.
Rocks on either side of the crest of oceanic ridges having equidistant locations from the crest were found to have similarities both in terms of their constituents their age and magnetic orientation.
As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading 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.
The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid ocean ridge is the spreading half rate and is equal to half of the spreading rate.
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.
Spreading rate is the rate at which an ocean basin widens due to seafloor spreading.
By the use of radiometric age dating and studying fossil ages it was also found out the rocks of the sea floor age is younger than the continental rocks.
Very little of the sea floor is older than 150 million years.
Ages for ocean floor between the oldest identified magnetic anomalies and continental crust are interpolated by geological estimates of the ages of passive continental margin segments.
Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.
As the magma and lava cool at seafloor spreading centers whatever magnetic field is present get ingrained into the rock.
The data is from four companion digital models of the age age uncertainty spreading rates and spreading asymmetries of the world s ocean basins.
This has happened many times throughout earth s history.
On the other hand the newest thinnest crust is located near the center of the mid ocean ridge the actual site of seafloor spreading.
The ocean plates spread and grow in opposite directions so rocks that are equidistance from the center have the same magnetic polarity and age.
Radiometric age dating and fossil ages.
The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century.
The oldest sediments so far recovered by a variety of methods including coring dredging and deep sea drilling date only to the jurassic period not exceeding about 200 million years in age.
It is called a geomagnetic reversal.
Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet.
Scientists use the magnetic polarity of the sea floor to determine the age.
When scientists studied the magnetic properties of the.
Spreading rates determine if the ridge is fast intermediate or slow.
