Pangaea
Pangaea is the Greek name for "entire Earth". Pangaea was the super-continent that was created by the continental drift. The theory of continental drift was thought up by Alfred Wegner. Although some scientists do not believe in Pangaea, there is lots of evidence that supports the theory. For example, fossils of the same dinosaurs and plants have been found in different continents. Also, the east coast of South America fits well together with the west coast of Africa. This suggests that the continents were together once.
Pangaea
A picture of the supercontinent Pangaea.
Convergent and Divergent Boundaries
Convergent boundaries are also known as destructive plate boundaries. Near a convergent boundary, earthquakes and volcanoes are common. The Himalayas and the Swiss Alps were formed at convergent boundaries. At these boundaries, two continental plates come together. The plate with more density dives under the other plate and sinks back down into the mantle. This process is called subduction.
A divergent boundary is also called a constructive boundary. At a divergent boundary, two plates move away from each other. Divergent boundaries form volcanic islands. Most active divergent plate boundaries are between oceanic plates.
A divergent boundary is also called a constructive boundary. At a divergent boundary, two plates move away from each other. Divergent boundaries form volcanic islands. Most active divergent plate boundaries are between oceanic plates.
Pacific Ring of Fire
The Pacific Ring of Fire is an area where many earthquakes and volcanic eruptions occur. It is located in the basin of the Pacific Ocean. 90% of the world's earthquakes occur around this area. It is also home to over 75% of the world's active and dormant volcanoes.
Mid-Ocean Ridge
The Mid-Ocean Ridge is the longest chain of mountains in the world. It is under the ocean. It runs through every ocean. It is 56,000 kilometers long. Volcanoes are often formed along the Mid-Ocean Ridge. Most hydrothermal vents are located here.
Layers of the Earth
There are 5 layers of the earth. They are the crust, the upper and lower mantle, the outer core, and the inner core. The crust is the thinnest and coldest layer of the Earth. It is directly under the ground. The upper mantle and lower mantle together are about 1800 miles thick. The outer core is approximately 1300 miles thick, and the inner core is 800 miles to the center of the Earth.
Layers of the Earth
These are the main layers of the Earth.
California's Geological Features ( In relation with plate tectonics )
Some of California's geological features include Mt. Shasta, Sierra Nevada, and the San Andreas Fault. Mt. Shasta and Sierra Nevada were created by two plates coming together at a convergent boundary. The San Andreas Fault was created by an earthquake, which is common at a transform boundary, where two plates slide past each other.
Fun Facts
Did you know......
Plates move using convection currents?
Plates move one centimeter a year?
California's Mt. Shasta was created at a convergent boundary?
Who was the first person that thought of a theory of continental drift?
Tuesday, April 21, 2009
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