Changes

== Magnetic Striping and Reversals ==

== Magnetic Striping and Reversals ==

Beginning in the 1950s, scientists, using [[magnetism|magnetic]] instruments (magnetometers) adapted from airborne devices developed during [[World War II]] to detect [[submarine]]s, began recognizing odd magnetic variations across the ocean floor, showing reversals in the Earth's magnetic field over it's history. This finding, though unexpected, was not entirely surprising because it was known that basalt—the iron-rich, volcanic rock making up the ocean floor—contains a strongly magnetic mineral (magnetite) and can locally distort compass readings. This distortion was recognized by Icelandic mariners as early as the late 18th century. More important, because the presence of magnetite gives the basalt measurable magnetic properties, these newly discovered magnetic variations provided another means to study the deep ocean floor.

Beginning in the 1950s, scientists, using [[magnetism|magnetic]] instruments (magnetometers) adapted from airborne devices developed during [[World War II]] to detect [[submarine]]s, began recognizing odd magnetic variations across the ocean floor, showing reversals in the Earth's magnetic field over its history. This finding, though unexpected, was not entirely surprising because it was known that basalt—the iron-rich, volcanic rock making up the ocean floor—contains a strongly magnetic mineral (magnetite) and can locally distort compass readings. This distortion was recognized by Icelandic mariners as early as the late 18th century. More important, because the presence of magnetite gives the basalt measurable magnetic properties, these newly discovered magnetic variations provided another means to study the deep ocean floor.

== Explanations of continental drift ==

== Explanations of continental drift ==