Sea floor spreading dating
Our editors will review what you’ve submitted and determine whether to revise the article.Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work!Magnetic stripes are the result of reversals of the Earth's field and seafloor spreading.New oceanic crust is magnetized as it forms and then it moves away from the ridge in both directions.The record of geomagnetic reversals preserved in volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronologic tool.Geophysicists who specialize in paleomagnetism are called paleomagnetists.Early in the 20th century, work by David, Brunhes and Mercanton showed that many rocks were magnetized antiparallel to the field. His intent was to test his theory that the geomagnetic field was related to the Earth's rotation, a theory that he ultimately rejected; but the astatic magnetometer became the basic tool of paleomagnetism and led to a revival of the theory of continental drift.Japanese geophysicist Motonori Matuyama showed that the Earth's magnetic field reversed in the mid-Quaternary, a reversal now known as the Brunhes-Matuyama reversal. Alfred Wegener first proposed in 1915 that continents had once been joined together and had since moved apart.
Paleomagnetism relied heavily on new developments in rock magnetism, which in turn has provided the foundation for new applications of magnetism.These include biomagnetism, magnetic fabrics (used as strain indicators in rocks and soils), and environmental magnetism.