Sea Floor Magnetism Theory

Sometimes for reasons unknown the magnetic poles switch positions.

Sea floor magnetism theory.

As oceanic crust forms and spreads moving away from the ridge crest it pushes the continent away from the ridge axis. The models show a ridge a about 5 million years ago b about 2 to 3 million years ago and c in the present. Paleomagnetism led the revival of the continental drift hypothesis and its transformation into theories of sea floor spreading and plate tectonics. Definition theory facts.

If the oceanic crust reaches a deep sea trench it sinks into the trench and is lost into the mantle. Harry hess s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. Check all that apply. This evidence was from the investigations of the molten material seafloor drilling radiometric age dating and fossil ages and the magnetic stripes.

Scientists discovered that new molten materials from inside earth create new crust. Strong evidence of seafloor spreading and plate tectonics. The pattern of magnetic strips shows that the seafloor is expanding at mid ocean ridges. Evidence of sea floor spreading.

This idea played a pivotal role in the development of the theory of plate tectonics which revolutionized geologic thought during the last quarter of the 20th century. North becomes south and south becomes north. Magnetic stripes are the result of reversals of the earth s field and seafloor spreading. It states that the earth s oceanic crust acts as a recorder of reversals in the geomagnetic.

What evidence supports hess s theory of seafloor spreading. The regions that hold the unique record of earth s magnetic field lie along the mid ocean ridges where the sea floor is spreading. 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. Was proven as patterns of magnetic field polarity preserved in seafloor basalt and by age dating of the rocks.

The magnetic stripes continue across the seafloor. During normal polarity the north and south poles are aligned as they are now. With reversed polarity the north and south poles are in the opposite position during wwii magnetometers attached to ships to search. Seafloor spreading theory that oceanic crust forms along submarine mountain zones known collectively as the mid ocean ridge system and spreads out laterally away from them.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century.