Sea Floor Spreading Definition Magnetic

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.

Sea floor spreading definition magnetic.

The minerals contained in the rocks are oriented opposite to the magnetic field. These age data also allow the rate of seafloor spreading to be. A process in which new ocean floor is created as molten material from the earth s mantle rises in margins between plates or ridges and spreads out. As a general rule fast ridges see spreading rate of more than 9 cm year.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. In the 20th century the magnetic survey was conducted in the mid ocean ridge in order to investigate evidence of sea floor spreading. The change in polarity is recorded in the magma which contributes to the alternating pattern of magnetic striping on the seafloor.

Plate tectonics plate tectonics seafloor spreading. Encyclopaedia britannica s editors oversee subject areas in which they have extensive knowledge whether from years of experience gained by working on that content or via study for an advanced degree. The earth s magnetic field the earth s magnetic field is thought to arise from the movement of liquid iron in the outer core as the planet rotates. Intermediate ridges have a spreading rate of 4 9 cm year while slow spreading ridges have a rate less than 4 cm year.

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. 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. The field behaves as if a permanent magnet were located near the center of the earth inclined about 11 degrees from the geographic axis of rotation fig. At spreading centres this crust is separated into parallel bands of rock by successive waves of emergent magma.

Sea floor spreading a. As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading. Earth s magnetic field because the outer core of earth is liquid iron that revolves around the solid inner core a magnetic field is produced that protects us from harmful things coming from space.