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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.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.Our editors will review what you’ve submitted and determine whether to revise the article.
Keith Runcorn constructed apparent polar wander paths for Europe and North America.
These include biomagnetism, magnetic fabrics (used as strain indicators in rocks and soils), and environmental magnetism.
As early as the 18th century, it was noticed that compass needles deviated near strongly magnetized outcrops.
In 1797, Von Humboldt attributed this magnetization to lightning strikes (and lightning strikes do often magnetize surface rocks).
In the 19th century studies of the direction of magnetization in rocks showed that some recent lavas were magnetized parallel to the Earth's magnetic field. Blackett provided a major impetus to paleomagnetism by inventing a sensitive astatic magnetometer in 1956.