What is used as evidence for seafloor spreading?
The age of Earth’s oceanic crust can be presented to show the pattern of seafloor spreading at the global scale. Encyclopædia Britannica, Inc. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.
What evidence is there 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 are the 4 evidences of seafloor spreading?
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.
What does seafloor spreading look like?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
What was the first evidence to support 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 are the 5 steps of seafloor spreading?
Terms in this set (7)
- 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 is the first step in the seafloor spreading process?
1. A long crack in the oceanic crust forms at a mid ocean ridge. 2. Molten material rises and erupts along the ridge.
What causes the seafloor to spread?
Sea-floor spreading is what happens at the mid-oceanic ridge where a divergent boundary is causing two plates to move away from one another resulting in spreading of the sea floor. As the plates move apart, new material wells up and cools onto the edge of the plates.