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What evidence is there of the continental drift theory?

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Quick Answer

According to National Geographic, sea floor spreading and plate tectonics indicate that the continents do move or shift, which supports continental drift theory. Fossils of the Mesosaurus, an ancient freshwater reptile found in the southern parts of South America and Africa, also indicate that the two continents could have once been one solid continent that drifted apart, since the reptile could not have swum across the ocean.

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Continental drift is a theory originally proposed by Alfred Wegener, who believed the continents were once one large continent known as Pangaea that later separated into several continents. One indication of this possibility is the appearance of the western African and eastern South American coasts, which look like two interlocking jigsaw puzzle pieces. Finding fossils of the Mesosaurus on the southern hemispheres of both continents is a further indication that the two continents were once together and later drifted apart.

Another indication of continental drift is tectonic activity and seafloor spreading. Scientists agree that continents rest on rocks called tectonic plates, which shift and move. Sea floor spreading further supports the continental drift theory. As molten rock rises from the Earth, it forms new crust between the plates. When this occurs, the sea floor grows wider, pushing the two continents apart. Sea floor spreading indicates that since the continents presently move apart, previous continental drift was possible and probable as well.

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    What is some evidence for the plate tectonics theory?

    A:

    Plate tectonics theory, formerly known as the theory of continental drift, is well supported in geology, geography and biology. It has the power to explain many phenomena, such as volcanoes and earthquakes. The theory provides a working model for analyses of phenomena that scientists observe. This explanatory power is, itself, strong evidence that the theory is correct.

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  • Q:

    What is the theory of continental drift?

    A:

    The theory of plate tectonics, formerly known as continental drift, is a working model that describes the movement of the continents and sea floor across the surface of the Earth. The theory explains many anomalous facts about Earth's geology, such as the present arrangement of landmasses.

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  • Q:

    What argument was used to dispute the theory of plate tectonics?

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    Andrew Alden of About explains that Australian geologist Sam Carey's theory of Earth expansion, the idea that the continents fit together properly only on a formerly smaller Earth, once rivaled the theory of plate tectonics. Carey's ideas expanded upon Wegener's continental-drift theory and hypothesised that the continents fit together properly on a shrunken Earth. From about the 1930s to the 1950s, this idea of Earth expansion remained a legitimate hypothesis.

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  • Q:

    What is the evidence for sea floor spreading?

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    Encyclopædia Britannica states that many pieces of evidence support the sea floor spreading theory of plate tectonics, including increased heat flow along mid-ocean ridges, geomagnetic anomalies near ocean ridges, thickness of marine sediments and age of sediments. Sea floor spreading was first proposed by geophysicist Harry Hess in 1960 after reviewing submarine data. The theory is the basis for modern plate tectonics that states plates in the Earth's crust move.

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