Evidence That The Ocean Floor Is Spreading

See also continental drift a veritable legion of evidence supports the seafloor spreading hypothesis.

Evidence that the ocean floor is spreading.

Variations in the intensity and polarity of earth s magnetic field are considered to be recorded in the remanent magnetism of the igneous rocks as they solidified and cooled through the curie temperature at the crest of an oceanic ridge and subsequently. Evidence for sea floor spreading. Subduction and sea floor spreading are processes that could alter the size and form of the ocean. His theory of sea floor spreading maintained that new basaltic oceanic crust forms at a midoceanic ridge and is slowly pushed away on both sides toward the continents as more new crust is produced.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. For instance the atlantic ocean is believed to be expanding because of its few trenches. 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. Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves.

Several types of evidence supported hess s theory of sea floor spreading. Wherever continents are bordered by deep sea trench systems as in the pacific ocean the ocean floor is plunged downward underthrusting the continents and ultimately reentering and dissolving in earth s mantle from which it had originated. Measurements indicate that new crust moves away from a ridge at. This evidence led scientists to look again at wegener s hypothesis of continental drift.