Evidence That The Ocean Floor Is 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.

Evidence that the ocean floor is spreading. 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. Measurements indicate that new crust moves away from a ridge at. 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.

In the 1960s geologist harry hess proposed that the sea floor was moving outward from the midoceanic ridges. Eruptions of molten material magnetic stripes in the rock of the ocean floor and the ages of the rocks themselves. Subduction and sea floor spreading are processes that could alter the size and form of the ocean. This evidence led scientists to look again at wegener s hypothesis of continental drift.

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. Several types of evidence supported hess s theory of sea floor spreading. Due to this continuous seafloor spreading occurs and makes atlantic ocean floor to be connected to other continental crust making the ocean gets wider over the time. 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.