What is the main idea of the plate tectonic theory?
The theory of plate tectonics states that the Earth’s solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle. Oceanic and continental plates come together, spread apart, and interact at boundaries all over the planet.
What 3 things 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 are the 4 main features of plate tectonics?
There are 4 main types of plate boundary including: convergent, divergent, subduction and transform – the type of boundary influences the features and events which occur.
What are the 6 evidences of plate tectonics?
Evidence for Plate Tectonics
- Shape of continents. From almost the creation of the first true maps of the Earth, people started seeing how continents would be able to fit together.
- Location of mountains and fossils.
- Earthquakes and Volcanoes.
- Hot Spot Volcanoes.
What is the evidence for tectonic plate movement?
Evidence for Tectonic Plates The continents are blocks of thick crust that are passengers on the tops of large tectonic plates (lithosphere) that move over a softer part of Earth’s mantle (asthenosphere). Earthquakes, mountain building and volcanic activity occur mostly at the boundaries of the moving plates.
Why do plate tectonic plates move apart at mid oceanic ridges?
Plates move apart at mid-ocean ridges where new seafloor forms. Between the two plates is a rift valley. Lava flows at the surface cool rapidly to become basalt, but deeper in the crust, magma cools more slowly to form gabbro. So the entire ridge system is made up of igneous rock that is either extrusive or intrusive.
What is the structure of the plates?
Plates. Plates are rigid bodies of rock that essentially float atop a region of partial melt called the asthenosphere. The plates comprise the lithosphere, composed of the crust (which is the rigid, outermost layer of the Earth) and the solid portion of the upper mantle.
What is the Rosetta Stone for plate tectonic theory?
This last observation is the “Rosetta Stone” for plate tectonic theory. It provides a means by which continents can drift apart. Instead of plowing directly over mantle, the continents are “passengers” on the tops of much thicker plates. The plates of crust and stiff mantle (lithosphere) move on the softer mantle layer beneath (asthenosphere).