Sea Floor Spreading Ages

Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch.

Sea floor spreading ages.

Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading. Spreading rates determine if the ridge is fast intermediate or slow. Harry hess s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. 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.

As the magma and lava cool at seafloor spreading centers whatever magnetic field is present get ingrained into the rock. This evidence was from the investigations of the molten material seafloor drilling radiometric age dating and fossil ages and the magnetic stripes. 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. 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.

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 mid atlantic ridge for instance separates the north american plate from the eurasian plate and the south american plate from the african plate the east pacific rise is a mid ocean ridge that runs through the eastern pacific ocean and separates the pacific plate from the north american. Spreading rate is the rate at which an ocean basin widens due to seafloor spreading.