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In the early 20th century, geologists such as Bernard Brunhes first noticed that some volcanic rocks were magnetized opposite to the direction of the local Earth's field. . The first systematic evidence for and time-scale estimate of the magnetic reversals were made by Motonori Matuyama in the late 1920s; he observed that rocks with reversed fields were all of early Pleistocene age or old
Earth's magnetic field deflects most of the solar wind, whose charged particles would otherwise strip away the ozone layer that protects the Earth from harmful ultraviolet radiation. [4] One stripping mechanism is for gas to be caught in bubbles of the magnetic field, which are ripped off by solar winds. [5]
The transition from the normal field to the reversed field lasted approximately 250 years, while the magnetic field remained reversed for approximately 440 years. During the transition, Earth's magnetic field declined to a minimum of 5% of its current strength, and was at about 25% of its current strength when fully reversed.
“It is really exciting that ancient artifacts from Mesopotamia help to explain and record key events in Earth history such as fluctuations in the magnetic field,” said study coauthor Mark ...
The study, published in the journal Communications Earth & Environment on May 2, found that Earth’s magnetic field, which is created by the motion of molten iron in Earth’s outer core, was ...
Earth’s outer core is made up of mostly molten iron, a liquid metal. Unpredictable changes in the way it flows cause the magnetic field around the Earth to shift, which then causes the magnetic ...
The history of geomagnetism is concerned with the history of the study of Earth's magnetic field. It encompasses the history of navigation using compasses, studies of the prehistoric magnetic field (archeomagnetism and paleomagnetism), and applications to plate tectonics. Magnetism has been known since prehistory, but knowledge of the Earth's ...
Polar drift is a geological phenomenon caused by variations in the flow of molten iron in Earth's outer core, resulting in changes in the orientation of Earth's magnetic field, and hence the position of the magnetic north- and south poles. The North magnetic pole is approximately 965 kilometres (600 mi) from the geographic North Pole. The pole ...