The Earth’s magnetic field, essential for navigation and protecting our planet from solar winds, has been a subject of intrigue and study in the field of geophysics, particularly in paleomagnetism. This branch of earth science delves into the historical changes of Earth’s magnetic field and its implications on geological processes.
One significant discovery in paleomagnetism was made by Japanese geophysicist Motonori Matuyama in 1929. Matuyama observed that Earth’s magnetic field has experienced numerous reversals throughout its history, with the most recent flip occurring around 780,000 years ago. This finding was pivotal, as it suggested that the magnetic poles have switched places multiple times, although the exact cause remains a mystery.
The research field took a monumental leap forward in 1963 with two groundbreaking studies. Canadian geophysicist Lawrence Morley and British geophysicists Frederick Vine and Drummond Matthews independently discovered magnetic “stripes” on the ocean floor. These stripes, displaying reversed magnetic polarities, were symmetrically aligned on either side of mid-ocean ridges. This observation led to the revolutionary conclusion that these ridges were sources of new molten rock, which upon cooling, preserved the magnetic-field polarity of that era. As new lava erupted, it captured the prevailing magnetic orientation, providing a record of Earth’s magnetic history. This discovery was crucial in validating the theory of seafloor spreading, a key component of plate tectonics.
