Ages Of Rocks On The Ocean Floor

Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet.

Ages of rocks on the ocean floor.

Sea floor age maps have been proven correct by the age dates calculated from hundreds of rock samples gathered from 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. The oldest seafloor is comparatively very young approximately 280 million years old. It is believed that continental rocks formed 3 billion years ago however the sediments samples from the ocean floor are found to be not exceeding 200 million years old.

This has happened many times throughout earth s history. 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. Contours of 20 million years are available as a layer that is currently set to invisible. When scientists studied the magnetic properties of the.

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. Scientists collected rock samples from the sea floor. A series of sedimentary beds was deposited on an ocean floor. The sedimentary rocks are uplifted and tilted.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. This dataset shows the age of the ocean floor along with the labeled tectonic plates and boundaries. The relative age of a rock then is its age in comparison with other rocks. Consider how the age of rocks is related to the shape of the seafloor you saw in step 3.

The ocean plates spread and grow in opposite directions so rocks that are equidistance from the center have the same magnetic polarity and age. The age of rocks in the ocean crust depends on where the rocks are collected. This image shows the age of rocks on the atlantic ocean seafloor. Examine the color code to understand how the age of rocks changes from the center to the edges of the ocean floor.

Other cratons in south africa australia and asia have continental rocks that are 3 billion years old. More proof for sea floor spreading comes from seismic studies indicating that earthquakes occur along the rift valley of a midoceanic ridge and the cross cutting fractures that offset it. It is found in the mediterranean sea and is a remnant of an ancient ocean that is disappearing between africa and europe. If you know the relative ages of two rock layers 1 do you know which is older and which is younger.

It is called a geomagnetic reversal. Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch. Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves.