What led to the theory of seafloor spreading?
Scientists discovered that as they moved away from the mid-ocean ridge, the samples of both the crustal rock and sediments on the ocean floor increased in age. The newest, youngest rock was closest to the mid-ocean ridge. This evidence supported the theory of seafloor spreading.
What observation supports the seafloor spreading theory?
Supporting Evidence for Seafloor Spreading First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.
What discoveries prompted the hypothesis of seafloor spreading?
In 1963, Vine and Matthews tied the discovery of magnetic stripes in the oceanic crust near ridges to Hess's concept of seafloor spreading. Harry Hess "An essay in Geopoetry" 1960 Contains the Sea Floor Spreading Hypothesis. It had good evidence and reached a wide audience.
What observation led Alfred Wegener’s theory of continental drift hypothesis?
Wegener also noticed that if you could shove western Europe and Africa together with North and South America, their coastlines would fit together very neatly. All this evidence led Wegener to believe that the continents were once connected but had separated and drifted apart.
How and where was seafloor spreading observed?
The age, density, and thickness of oceanic crust increases with distance from the mid-ocean ridge. Geomagnetic ReversalsThe magnetism of mid-ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century.
What is the hypothesis of seafloor spreading?
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.
How was the seafloor discovered?
Harry Hess was a geologist and Navy submarine commander during World War II. Part of his mission had been to study the deepest parts of the ocean floor. In 1946 he had discovered that hundreds of flat-topped mountains, perhaps sunken islands, shape the Pacific floor.
What two scientists proposed the theory of seafloor spreading in the early 1960s?
The idea that the seafloor itself moves and also carries the continents with it as it spreads from a central rift axis was proposed by Harold Hammond Hess from Princeton University and Robert Dietz of the U.S. Naval Electronics Laboratory in San Diego in the 1960s.
Where was seafloor spreading first observed?
Mid-Atlantic Ridge In the early 1960s, dating of ocean-core samples showed that the ocean floor was younger at the Mid-Atlantic Ridge but progressively older in either direction, confirming the reality of seafloor spreading.
What is the evidence for seafloor spreading quizlet?
What three types of evidence provided support for the theory of sea floor spreading? eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves.
What did scientists notice when they observed the mid-ocean ridge?
They discovered this by finding the age of rock samples obtained by drilling in the ocean floor. How did scientists discover that rocks farther away from the mid-ocean ridge were older that those near the ridge? Oceanic crust near the mid-ocean ridge is younger than the crust farther from the ridge.
Which best summarizes the hypothesis of seafloor spreading?
Which best summarizes the hypothesis of seafloor spreading? Lava erupts from the mid-ocean ridge and is carried away as the floor of the ocean spreads apart.
What did scientists observe in the ocean floor which indicates that the Pacific ocean is becoming smaller?
Since subduction rates are much greater than the rates of producing new seafloor at the mid-oceanic ridges, simply because there are more spreading regions than subduction zones, the result is that the Pacific Ocean is shrinking on a geological time scale.