What evidence support the theory of plate tectonics?
There is variety of evidence that supports the claims that plate tectonics accounts for (1) the distribution of fossils on different continents, (2) the occurrence of earthquakes, and (3) continental and ocean floor features including mountains, volcanoes, faults, and trenches.
What led to the discovery of plate tectonics?
Plate tectonic theory had its beginnings in 1915 when Alfred Wegener proposed his theory of “continental drift.” Wegener proposed that the continents plowed through crust of ocean basins, which would explain why the outlines of many coastlines (like South America and Africa) look like they fit together like a puzzle.
What evidence was discovered in the 1960’s that helped support the theory of plate tectonics?
Following World War II, even more evidence was uncovered which supports the theory of plate tectonics. In the 1960’s a world-wide array of seismometers were installed to monitor nuclear testing, and these instruments revealed a startling geological phenomenon.
What evidence led to the discovery of the ocean floor and tectonic plates?
In particular, four major scientific developments spurred the formulation of the plate-tectonics theory: (1) demonstration of the ruggedness and youth of the ocean floor; (2) confirmation of repeated reversals of the Earth magnetic field in the geologic past; (3) emergence of the seafloor-spreading hypothesis and …
Who came up with the theory of seafloor spreading?
Harry H. Hess
What data taken from the ocean floor led to the theory of plate tectonics?
In deep trenches like those found off the coast of South America and Japan, the spreading ocean floor was forced down below the thick continents in regions he called subduction zones. Hess’s theory of “seafloor spreading” offered a compelling driving mechanism for Wegener’s continental drift, but it needed more proof.
What evidence supports the theory of ocean floor?
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 does the evidence of paleomagnetism explain the movement of spreading centers?
Magnetic reversals show up as bands of alternating polarity in the slowly spreading seafloor. This explanation of magnetic striping by paleomagnetism convinced scientists that new oceanic crust was being continually formed at mid-oceanic ridges. Seafloor spreading was accepted as a reality.
What are the three pieces of evidence for seafloor 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.
What causes seafloor spreading?
Seafloor spreading creates new oceanic crust at a mid-ocean ridge. When this new material reaches the end of the plate and comes into contact with another plate, whether continental or not, a convergent or a transform boundary will occur.
What are the 4 steps of seafloor spreading?
What are the 4 steps of seafloor 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 is the difference between seafloor spreading and continental drift?
Continental drift is a very similar process to seafloor spreading. Continental drift is the gradual movement of continental plates over the Earth’s surface over time. Seafloor spreading is the formation of new areas of oceanic crust due to the upwelling of magma as oceanic aparts pull apart.
What is the major difference between continental drift and plate tectonics?
Plate tectonics explains why Earth’s continents are moving; the theory of continental drift did not provide an explanation. Therefore, the theory of plate tectonics is more complete.
What can you say about the theory proposed by Alfred Wegener?
Continental drift was a theory that explained how continents shift position on Earth’s surface. Set forth in 1912 by Alfred Wegener, a geophysicist and meteorologist, continental drift also explained why look-alike animal and plant fossils, and similar rock formations, are found on different continents.
What would the Earth look like without plate tectonics?
Over millions of years, continents drift across Earth’s surface, going from one climate zone to another. Without plate tectonics, Earth would not have its diverse geography, which provides a wide range of habitats. Plate tectonics is also responsible for hydrothermal vents on the ocean floor.
Is plate tectonics essential for life?
Plate activity on Earth has helped to regulate the level of carbon dioxide over the eons. The same weathering that pulls nutrients from mountaintops down into the oceans also helps to remove carbon dioxide from the atmosphere. The Alaska Range continues to grow today as a result of plate tectonics.
What would happen if Earth’s plates stopped moving?
If all plate motion stopped, Earth would be a very different place. Erosion would continue to wear the mountains down, but with no tectonic activity to refresh them, over a few million years they would erode down to low rolling hills.
Will plate tectonics ever stop?
After the planet’s interior cooled for some 400 million years, tectonic plates began shifting and sinking. This process was stop-and-go for about 2 billion years. In another 5 billion years or so, as the planet chills, plate tectonics will grind to a halt.
What will happen if plates move?
When the plates move, they will eventually collide. These collisions cause earthquakes, tsunamis, and volcanoes. Earthquakes usually happen when two plates slide past each other. Volcanoes form when one plate sinks under the other plate allowing lava/magma to seep through and build up to form a volcano.
What ll happen when plate tectonics grinds to a halt?
Earth would likely enter a single lid regime, a completed jigsaw of titanic slabs that will no longer drift or sink. Mountain building will stop, but Earth will still have an atmosphere, so erosion by wind and waves will shave down the mighty peaks to hilly plateaus.
How long will plate tectonics last?
As a likely consequence, plate tectonics will come to an end, and with them the entire carbon cycle. Following this event, in about 2–3 billion years, the planet’s magnetic dynamo may cease, causing the magnetosphere to decay and leading to an accelerated loss of volatiles from the outer atmosphere.
How many tectonic plates are there?
seven