Map Of Age Of Ocean Floor And Explanation

Sio reference series 93 30 scripps institution of oceanography.

Map of age of ocean floor and explanation.

They noticed first that these ridges stretched on for thousands of kilometers in long continuous mountain chains that wound around the earth s surface almost. Therefore seafloor dating isn t that useful for studying plate motions beyond the cretaceous. Examine the color code to understand how the age of rocks changes from the center to the edges of the ocean floor. A digital age map of the ocean floor.

Rather than height of the ocean floor above a base or reference level the depth of the ocean is of interest. The data is from four companion digital models of the age age uncertainty spreading rates and spreading asymmetries of the world s ocean basins. Contours of 20 million years are available as a layer that is currently set to invisible. The data are described in a data and analysis note in the journal of geophysical research 1997 entitled digital isochrons of the world s ocean floor.

In the 1950s and 1960s marine geologists such as bruce heezen marie tharp and henry menard used data from echo sounders to map ocean ridges in the north atlantic and the pacific. This graphic shows several ocean floor features on a scale from 0 35 000 feet below sea level. 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. Answer the questions below.

The survey data was used to create three dimensional relief maps of the ocean floor and by 1953 american oceanic cartographer marie tharp had created the first of several maps that revealed the presence of an underwater mountain range. This dataset shows the age of the ocean floor along with the labeled tectonic plates and boundaries. The following features are shown at example depths to scale though each feature has a considerable range at which it may occur. 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.

Shortly after the conclusion of world war ii sonar equipped vessels crisscrossed the oceans collecting ocean depth profiles of the seafloor beneath them. 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. 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. For that geologists date and study continental crust.

Consider how the age of rocks is related to the shape of the seafloor you saw in step 3.