What evidence in rocks supports the theory of seafloor spreading?
What evidence in rocks supports the theory of 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 3 pieces of evidence for sea floor spreading?
Several types of evidence from the oceans supported Hess’s theory of sea-floor spreading-evidence from molten material, magnetic stripes, and drilling samples. This evidence also led sci- entists to look again at Wegener’s theory of continental drift.
Which evidence proved that the seafloor is 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 observations of the ocean floor supported the sea floor spreading hypothesis?
These observations are:
- The seafloor has a large mountain range running through it. Deep trenches are found far from the ridges.
- The magnetic polarity of the seafloor changes. The center of the ridge is of normal polarity.
- The youngest seafloor is at the ridge. The oldest is farthest from the ridge.
What are 4 pieces of evidence for seafloor 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 are 2 pieces of evidence supporting seafloor spreading?
Is sea floor spreading a fast or slow process?
It spreads about 6-16 centimeters (3-6 inches) every year. There is not an ocean trench at the East Pacific Rise, because the seafloor spreading is too rapid for one to develop!
What is the most prominent feature on the ocean floor?
global mid-ocean ridge system
Though hidden beneath the ocean surface, the global mid-ocean ridge system is the most prominent topographic feature on the surface of our planet.
What happens when a piece of crust is subducted?
Where two tectonic plates meet at a subduction zone, one bends and slides underneath the other, curving down into the mantle. (The mantle is the hotter layer under the crust.) At a subduction zone, the oceanic crust usually sinks into the mantle beneath lighter continental crust.
What happens during seafloor spreading?
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. Eventually, the crust cracks.
How is the spreading hypothesis of the seafloor supported?
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.
How is the age of the Earth’s crust related to seafloor spreading?
The age of Earth’s oceanic crust can be presented to show the pattern of seafloor spreading at the global scale. Measurements of the thickness of marine sediments and absolute age determinations of such bottom material have provided additional evidence for seafloor spreading.
How are magnetic anomalies related to seafloor spreading?
Seafloor spreading. Investigations of oceanic magnetic anomalies have further corroborated the seafloor spreading hypothesis. Such studies have shown that the strength of the geomagnetic field is alternately anomalously high and low with increasing distance away from the axis of the mid-ocean ridge system.
How does the spreading of the seafloor affect plate tectonics?
This idea played a pivotal role in the development of plate tectonics, a theory that revolutionized geologic thought during the last quarter of the 20th century. seafloor spreading and magnetic striping Rising magma assumes the polarity of Earth’s geomagnetic field before it solidifies into oceanic crust.