Age Pattern Of Ocean Floor

It is called a geomagnetic reversal.

Age pattern of ocean floor.

The following features are shown at example depths to scale though each feature has a considerable range at which it may occur. The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. For that geologists date and study continental crust. Contours of 20 million years are available as a layer that is currently set to invisible.

Therefore seafloor dating isn t that useful for studying plate motions beyond the cretaceous. It is composed of several layers not including the overlying sediment. Continental shelf 300 feet continental slope 300 10 000 feet abyssal plain 10 000 feet abyssal hill 3 000 feet up from the abyssal plain seamount 6 000 feet. This graphic shows several ocean floor features on a scale from 0 35 000 feet below sea level.

Oceanic crust is about 6 km 4 miles thick. Rather than height of the ocean floor above a base or reference level the depth of the ocean is of interest. Because of this correlation between age and subduction potential very little ocean floor is older than 125 million years and almost none of it is older than 200 million years. This has happened many times throughout earth s history.

Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. Oceanic crust the outermost layer of earth s lithosphere that is found under the oceans and formed at spreading centres on oceanic ridges which occur at divergent plate boundaries. In 1966 vine and matthews and also morley working independently compared these known ages of magnetic reversals with the magnetic striping pattern found on the ocean floor. Examine the color code to understand how the age of rocks changes from the center to the edges of the ocean floor.

The data is from four companion digital models of the age age uncertainty spreading rates and spreading asymmetries of the world s ocean basins. Answer the questions below. Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves. To get the dependence on x one must substitute t x v ax l where l is the distance between the ridge to the continental shelf roughly half the ocean width and a is the ocean basin age.

This dataset shows the age of the ocean floor along with the labeled tectonic plates and boundaries. Age of earth s oceanic crust the age of earth s oceanic crust can be presented to show the pattern of seafloor spreading at the global scale. 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. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.