How are the theories of continental drift and plate tectonics similar?
Continental Drift as proposed by Alfred Wegener was theory that all of the continents had once been connected as part of a super continent he called Pangea. Plate tectonics is Wegener theory of continental drift reworked. The force needed to move the continents is proposed to be convection currents in the mantle.
How does plate tectonics incorporate ideas from continental drift?
The crust is broken up into giant tectonic plates that ride atop the magma, hot melted-rock material that makes up much of the interior of the Earth. Over millions of years, the continents drift into new configurations. Convection in the molten rock of Earth’s mantle drives the movement of the plates.
In what major way does the plate tectonic theory depart from the continental drift theory?
A major departure of the plate tectonics theory from the continental drift hypothesis is that large plates contain both continental and ocean crust and the entire plate moves.
What is an example of plate tectonics?
This happens at the mid-ocean ridges, where seafloor spreading and volcanic activity continuously add new oceanic crust to the oceanic plates on both sides. Examples are the Mid-Atlantic Ridge and East Pacific Rise. Divergent boundaries on continents are more rare, but also exist. An example is the East African rift.
How many plate tectonics are there in total?
seven
What are the 2 types of crust on Earth?
Earth’s crust is divided into two types: oceanic crust and continental crust.
How heavy is a tectonic plate?
The thickness of tectonic plates in general varies roughly in the range 100-200 km depending upon whether we are talking about oceanic or continental lithosphere; let’s call it 150 km or 1.5× 105 m. The density of lithospheric material varies in the range 2700-2900 kg m-3; we’ll use 2800 kg m-3.
Are continents the same as plates?
The continents are embedded in the plates. Many continents occur in the middles of plates, not at their boundaries or edges. Plates are composed of the Earth’s crust and upper mantle, which are collectively called the lithosphere. This layer is like an eggshell compared to the total thickness of the Earth.