The topography of the seafloor gives us a nice clue about the seafloor spreading. This can be seen in the highest of the underwater features. The mid-ocean ridge is the highest. It is the place where the magma comes out, cools off, and constantly creates new rocks, or rather crust.
What evidence exists for sea floor spreading?
Evidence for Sea-Floor Spreading. Several types of evidence supported Hess’s 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. This evidence led scientists to look again at Wegener’s hypothesis of continental drift. Evidence for Sea-Floor Spreading.
What is the theory 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. 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.
What happens during the process of seafloor spreading?
What are the steps in the process of sea floor spreading?
- Magma comes out of the rift valley.
- Magma cools to rock and hardens.
- Rock is pushed away as new rock is formed at MOR.
- Oceanic crust and continental crust meet at the trench.
- Oceanic crust bends down under the continental crust.
- Gravity pulls rock towards mantle.
- Rock melts to mantle.
What causes seafloor spreading?
Seafloor spreading occurs when two large plates collide and push against each other. The result is that new oceanic crust is created between them. The direction that the plates are moving with respect to each other is called their dip. At places where they dip down towards the middle of the earth there are great mountain ranges called orogens.
How does the topography of the seafloor give evidence?
How does the topography of the seafloor give evidence for seafloor spreading? How does seafloor spreading fit into the idea that continents move about on Earth's surface? If the floor is pushing on the plates, while creating 'new earth' then the surface will move around, also causing the continents to move.
What evidence supports seafloor spreading in 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.
Does sea-floor topography provide evidence for plate tectonics?
Ocean topography also provided evidence of plate tectonic theory. Nineteenth century surveys of the oceans indicated that rather than being flat featureless plains, as was previously thought, some ocean areas are mountainous while others plummet to great depths.
How do we know the seafloor is spreading?
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.
How do ocean ridges and deep sea trenches support the theory of seafloor spreading?
Matching magnetic lines of reversal along both sides of the ocean ridge also lends support to the theory of sea floor spreading. The subduction zones which form the deep sea trenches also support the theory of sea floor spreading.
Which of the following is the single best evidence in support of the concept of seafloor spreading?
Evidence of Magnetic stripes It was the greatest support of sea fall spreading.
How is paleomagnetism evidence of seafloor spreading?
Hence, paleomagnetic rocks (paleo: denoting rocks) on either side of the mid-ocean or submarine ridges provide the most important evidence to the concept of Sea Floor Spreading. Magnetic field records also provide information on the past location of tectonic plates.
What are the evidences for the seafloor spreading hypothesis?
Reveals how seafloor topography, magnetic polarity, and age are evidence for the sea floor spreading hypothesis.
Who came up with the idea of seafloor spreading?
Seafloor spreading wedded together the mantle convection idea of Holmes, the continental drift idea of Wegener, new bathymetric and magnetic data from the seafloor, and made a coherent single idea.
What mechanism is used to drift continents?
Seafloor spreading is the mechanism for Wegener’s drifting continents. Convection currents within the mantle take the continents on a conveyor-belt ride of oceanic crust that, over millions of years, takes them around the planet’s surface. The spreading plate takes along any continent that rides on it.
Why did Harry Hess call his idea an essay in geopoetry?
Harry Hess called his idea “an essay in geopoetry,” possibly because so many ideas fit together so well, or more likely because at the time he didn’t have all the seafloor data he needed for evidence.
What happens when oceanic crust spreads away from the ridge crest?
As oceanic crust forms and spreads, moving away from the ridge crest, it pushes the continent away from the ridge axis.
Where is the oceanic crust created?
Since new oceanic crust is created at the mid-ocean ridges, either Earth is getting bigger (which it is not) or oceanic crust must be destroyed somewhere. Since the oldest oceanic crust was found at the edges of the trenches, Hess hypothesized that the seafloor subducts into Earth’s interior at the trenches to be recycled in the mantle.
Why is the oldest crust coldest?
The oldest crust is coldest and lies deepest in the ocean because it is less buoyant than the hot new crust.
What is the transition zone between land and sea?
Submerged, outer edge of the continent. The transition zone from land to deep sea. It is where continental crust gives way to oceanic crust.
What pattern does hot material rise and cool material sink in?
Hot material rises and cool material sinks in a circular pattern.
Where are volcanoes located on an oceanic plate?
Line of volcanoes on an oceanic plate; the volcanoes are above a subducting oceanic plate and near a deep sea trench.
What is a plate boundary?
Plate boundary where two plates slide past one another.
How many continents can a divergent plate boundary create?
Divergent plate boundary within a continent. This will create two continents.
What are the three major types of plate boundaries?
These are the three major types of plate boundaries. Apart, together, or past
What is the difference between active and passive margin?
active margin. Part of a plate that has a lot of geological activity; this is because this part of the plate meets another plate. passive margin. Part of a plate that has no geological activity; this part of the plate is not meeting with another plate. supercontinent cycle.
The Process of Sea Floor Spreading
The Subduction Process
- The highly dense oceanic crust that is formed after a progressive spreading is destined to two possible occurrences. It can either be subducted into the ocean deep trench or continue to spread across the ocean until it reaches a coast. Subduction is the slanting and downward movement of the edge of a crustal plate into the mantle beneath another plate. It occurs when an incredibly de…
Evidence of Sea Floor Spreading
- Harry Hess’s hypothesis about seafloor spreading had collected several pieces of evidence to support the theory. This evidence was from the investigations of the molten material, seafloor drilling, radiometric age dating and fossil ages, and the magnetic stripes. This evidence however was also used to support the Theory of Continental drift.