Magnetic Striping Of Ocean Floor

Magnetic evidence for seafloor spreading explains how magnetic polarity frozen into seafloor basalts reveals evidence for the creation of new seafloor at mid ocean ridges.

Magnetic striping of ocean floor.

Coast and geodetic survey ship pioneer in a joint project with the u s. Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. In the early 1960s scientists such as heezen hess and dietz had begun to theorise that mid ocean ridges mark structurally weak zones where the ocean floor was being ripped in two lengthwise along the ridge crest see the previous paragraph.

The discovery adds a key element to the theory of plate tectonics. 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. This finding though unexpected. Discovery of magnetic striping on ocean floor.

It is as if the sea floor was a giant tape recorder with twin tapes emerging from the mid atlantic ridge recording the earth s magnetism at the time they emerge and then traveling in opposite directions. Each strip therefore represents an epoch of one or the other magnetic polarity and the symmetry is also explained. When magma flows out of a mid ocean ridge small magnetic minerals in the magma align themselves to point in the direction of the earth s current magnetic north. The discovery of magnetic striping called for an explanation.

Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor. Among the new findings was the discovery of zebra stripe like magnetic patterns for the rocks of the ocean floor. These patterns were unlike any seen for continental rocks. Navy and the scripps institution of oceanography tows the first marine magnetometer and finds magnetic striping on the seafloor off the west coast.

Magnetic striping and polar reversals beginning in the 1950s scientists using magnetic instruments magnetometers adapted from airborne devices developed during world war ii to detect submarines began recognizing odd magnetic variations across the ocean floor.