Magnetite Ocean Floor

As magma cools it locks in a recording of the earth s magnetic orientation or polarity at the time of fooling.

Magnetite ocean floor.

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 the magnetite uralite and other minerals can be exposed by etching away the enclosing calcite with hydrochloric acid. The reason tiny grains of magnetite found within the volcanic basalt that make up the ocean floor behave like little magnets. These grains of magnetite can align themselves with orientation of the earth s magnetic field. Magnetic striping of the sea floor after mid ocean ridges and trenches were discovered more evidence was discovered that helped to support the theory that the continents had moved around.

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. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks. Magnetic striping magnetic minerals are found in rocks. This distortion was recognized by icelandic mariners as early as the late 18th century.