Sea Floor Spreading Age Evidence

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

Sea floor spreading age evidence.

Sea floor age maps have been proven correct by the age dates calculated from hundreds of rock samples gathered from the ocean floor. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading. Rocks on either side of the crest of oceanic ridges having equidistant locations from the crest were found to have similarities both in terms of their constituents their age and magnetic orientation. Evidence of sea floor spreading.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Chapter 1 section 4. Evidence for sea floor spreading. The ocean plates spread and grow in opposite directions so rocks that are equidistance from the center have the same magnetic polarity and age.

This has happened many times throughout earth s history. It is called a geomagnetic reversal. 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. Evidence for seafloor spreading nature of oceanic rocks around mid ocean ridges.

Harry hess s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. 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. Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves.

Several types of evidence supported hess s theory of sea floor spreading. 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. When scientists studied the magnetic properties of the. Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet.

Spreading rates determine if the ridge is fast intermediate or slow. 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. 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. This evidence was from the investigations of the molten material seafloor drilling radiometric age dating and fossil ages and the magnetic stripes.