Other cratons in south africa australia and asia have continental rocks that are 3 billion years old.
Ages of rocks on the ocean floor.
They found out that rock samples that were closer to mid ocean.
The relative age of a rock then is its age in comparison with other rocks.
As the magma and lava cool at seafloor spreading centers whatever magnetic field is present get ingrained into the rock.
The age of rocks in the ocean crust depends on where the rocks are collected.
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 magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century.
Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet.
Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch.
Contours of 20 million years are available as a layer that is currently set to invisible.
Consider how the age of rocks is related to the shape of the seafloor you saw in step 3.
If you know the relative ages of two rock layers 1 do you know which is older and which is younger.
Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves.
A series of sedimentary beds was deposited on an ocean floor.
Scientists collected rock samples from the sea floor.
This image shows the age of rocks on the atlantic ocean seafloor.
It is called a geomagnetic reversal.
This dataset shows the age of the ocean floor along with the labeled tectonic plates and boundaries.
This has happened many times throughout earth s history.
The data is from four companion digital models of the age age uncertainty spreading rates and spreading asymmetries of the world s ocean basins.
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.
The sediments hardened into sedimentary rock.
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.
The oldest seafloor is comparatively very young approximately 280 million years old.
Examine the color code to understand how the age of rocks changes from the center to the edges of the ocean floor.
The sedimentary rocks are uplifted and tilted.
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.
