What is the evidence for seafloor spreading?
Abundant evidence supports the major contentions of the seafloor-spreading theory. 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 is evidence of seafloor spreading quizlet?
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. What happens at ocean trenches?
What are three pieces of evidence for seafloor spreading?
What three types of evidence provide support for the theory of sea-floor spreading? Evidence from molten material, magnetic strips and drilling samples support the theory of sea-floor spreading.
Whats is happening at slit B?
What is happening at slit B? What feature occurs at the corresponding location on the seafloor? Magma is being forced upward creating new ocean floor. The feature that occurs at slit B stands for the central valley of the mid ocean ridge.
What two additional categories of evidence supported the original seafloor spreading hypothesis?
Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.
What is the major evidence that sea floor spreading creates new lithosphere explain your answer?
The record of magnetic reversals is carried away from each side of the spreading center of a mid-ocean ridge, showing that the molten rock is creating new lithosphere.
What’s the first step of seafloor spreading?
1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge.
How does density and temperature affect sea floor spreading?
The cooler denser mantle sinks causing subduction and the hotter mantle rises to the surface causing sea floor spreading.
What geological feature is formed at the two side slits?
Rift Valleys When divergent boundaries occur in continental plates, a different geological feature, called a rift valley, is formed.
Which evidence originally supported houses idea of seafloor spreading in 1968?
Which evidence originally supported Hess’s idea of seafloor spreading in 1968? Younger rocks are closer to mid-ocean ridges.
What evidence helped give strong support for the hypothesis of seafloor spreading at mid ocean ridges?
This hypothesis was supported by several lines of evidence: (1) at or near the crest of the ridge, the rocks are very young, and they become progressively older away from the ridge crest; (2) the youngest rocks at the ridge crest always have present-day (normal) polarity; and (3) stripes of rock parallel to the ridge …
What is the importance of seafloor spreading in understanding the origin of the plate?
Significance. Seafloor spreading helps explain continental drift in the theory of plate tectonics. When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere.
What evidence supports the seafloor spreading hypothesis?
A veritable legion of evidence supports the seafloor spreading hypothesis. Studies conducted with thermal probes, for example, indicate that the heat flow through bottom sediments is generally comparable to that through the continents except over the mid-ocean ridges, where at some sites the heat flow measures three…
What is seafloor spreading in plate tectonics?
plate tectonics: Seafloor spreading. As upwelling of magma continues, the plates continue to diverge, a process known as seafloor spreading. Samples collected from the ocean floor show that the age of oceanic crust increases with distance from the spreading centre—important evidence in favour of this process. These….
What is the difference between seafloor spreading and convection?
Vocabulary. Seafloor spreading is a geologic process in which tectonic plate s—large slabs of Earth’s lithosphere —split apart from each other. Seafloor spreading and other tectonic activity processes are the result of mantle convection. Mantle convection is the slow, churn ing motion of Earth’s mantle.
How does subduction cause oceanic spreading?
Spreading, which originates at oceanic ridges, is compensated (to conserve surface area on the planet) by subduction—the process whereby the seafloor flexes and sinks along inclined trajectories into the Earth’s interior—at deep-sea trenches. Closure of ocean basins by subduction of the seafloor results….