Sea Floor Spreading Age Evidence

Spreading rates determine if the ridge is fast intermediate or slow.

Sea floor spreading age evidence.

Evidence for sea floor spreading. Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. Chapter 1 section 4. Evidence of sea floor spreading.

Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. 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. Every so often it has occurred over 170 times over the past 100 million years the poles will suddenly switch. It is called a geomagnetic reversal.

Sea floor age maps have been proven correct by the age dates calculated from hundreds of rock samples gathered from the ocean floor. Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves. 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. 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. This evidence was from the investigations of the molten material seafloor drilling radiometric age dating and fossil ages and the magnetic stripes. Every once in a while the currents in the liquid core which create the earth s magnetic field reverse themselves. When scientists studied the magnetic properties of the.

This has happened many times throughout earth s history. The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Evidence for seafloor spreading nature of oceanic rocks around mid ocean ridges. These age data also allow the rate of seafloor spreading to be determined and they show that rates.

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. 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. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor 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.