The Rocks On The Ocean Floor Are Magnetic

Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.

The rocks on the ocean floor are magnetic.

Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. Select the two correct answers. Identify the factors that cause magnetic stripes to form along the ocean floor. This evidence led scientists to look again at wegener s hypothesis of continental drift.

Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks. The oceanic crust displays a pattern of magnetic lines parallel to the ocean ridges frozen in the basalt. Magnetic direction of rock changes as earth s magnetic poles drift.

Evidence for sea floor spreading. The ocean floor is mainly made up of basalt which is formed as a result of underwater volcanic activity. A symmetrical pattern of positive and negative magnetic lines emanates from the mid ocean ridge. Plates move as new rock forms which causes magnetic direction to skew away.

This is how scientists get the age of the seafloor. Basalts contain magnetic minerals which get aligned in the direction of the magnetic field when the rock solidifies. Magma acquires the magnetic direction present on earth when it hardens into rock 3. 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.

Evidence from molten material. The oldest rocks on the ocean floor are 200 mya very young when compared with the oldest continental rocks which date from 3 8 billion years ago. The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. These stripes of normal and reverse magnetic fields with different sizes can be matched with the geomagnetic reversals records obtained from continental rocks already dated.

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. Paleomagnetic procedure collecting samples on land. 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. These patterns were unlike any seen for continental rocks.

Several types of evidence supported hess s theory of sea floor spreading. The volcanic and sedimentary rocks record the paleomagnetism at the time when that part of the ocean floor was created. New rock is formed by magma at the mid ocean ridges and the ocean floor spreads out from this point. Magnetic striping magnetic minerals are found in rocks.