Tectonic Plates
Do we really know what is happening in our planet or how the Tectonic Plates affect our Earth? Well if you would like to know about tectonics plates,you are in the right place. There are three tectonic plate movements, they are called Convergent Boundaries, Divergent Boundaries and the Transform Boundaries. Each of those plate boundaries are doing different movements. The convergent boundaries move toward each other, divergent boundaries move apart from each other, and transform boundaries move side by side (so imagine sliding in opposite directions).
Theory of Pangaea
German climatologist and geophysicist Alfred Wagener who, in 1915, created the theory of Pangaea. The theory of Pangaea is that all present continents were once together and collectively known as a'supercontinent' called a Pangaea. The word 'Pangaea' means 'all lands' in Greek, accurately defining the way the continents were 200 millions years ago before it split up. These split-up pieces drifted slowly apart and became the way they are today. Even until now, the shape of the Earth surface is still changing, and it will be forever, as long as the mantle underneath the Earth's crust gets heated and convection currents in the magma keeps dragging the plates. The Pangaea theory was treated with some disbelif when it was first raised. But since then, there have been much evidence to support this theory. Some evidence to support the theory was the types of rocks found on each continent today show similar strata and ages. Mountain range on the coast of West Africa disappear then suddenly reappear again on the coast of South America, identical plant and animal fossils of the same age have been found in rocks in Africa and South America. Those plants and animals couldnt have swam from a continent to another.
Convergent Boundaries
Are you wondering what a Convergent Boundary is? A Convergent boundary occurs when two plates collide. When they collide they either create a volcano, earthquake or a mountain range depending on the area of collision. The plates move only a couple centimeters per year and the collision of two plates are very slow and last millions of years. You can think of when you get into a front end car crash is simular to a Convergent Boundary. It is also known as the Subduction Boundary.
There are 3 types of convergent boundaries:
1. Continental to Continental, which makes mountains
2. Oceanic to Oceanic, which makes new crust
3. Continental to Oceanic, which makes volcanoes
Continental to Continental~ When two Continental plates come together and the land above it begins to crumble up creating mountain ranges.
Oceanic to Oceanic~ When two Oceanic plates come together
Continental to Oceanic~ When one Oceanic plate and one Continental plate come together one plate (the denser plate, which is the Oceanic plate)is forced under the other, then the plate gets pushed down farther and farther into the Earth and begins to heat up and eventually melt causing magma to rise and create volcanoes.
There are 3 types of convergent boundaries:
1. Continental to Continental, which makes mountains
2. Oceanic to Oceanic, which makes new crust
3. Continental to Oceanic, which makes volcanoes
Continental to Continental~ When two Continental plates come together and the land above it begins to crumble up creating mountain ranges.
Oceanic to Oceanic~ When two Oceanic plates come together
Continental to Oceanic~ When one Oceanic plate and one Continental plate come together one plate (the denser plate, which is the Oceanic plate)is forced under the other, then the plate gets pushed down farther and farther into the Earth and begins to heat up and eventually melt causing magma to rise and create volcanoes.
Divergent Boundaries
Places where plates are coming apart are called divergent boundaries. As shown in the drawing below, when Earth's brittle surface layer (the lithosphere) is pulled apart, it typically breaks along parallel faults that tilt slightly outward from each other. As the plates separate along the boundary, the block between the faults cracks and drops down into the soft, plastic interior (the asthenosphere). The sinking of the block forms a central valley called a rift. Magma (liquid rock) seeps upward to fill the cracks. In this way, new crust is formed along the boundary. Earthquakes occur along the faults, and volcanoes form where the magma reaches the surface. Where a divergent boundary crosses the land, the rift valleys which form are typically 30 to 50 kilometers wide. Where a divergent boundary crosses the ocean floor, the rift valley is much narrower, only a kilometer or less across, and it runs along the top of a midoceanic ridge. Oceanic ridges rise a kilometer or so above the ocean floor and form a global network tens of thousands of miles long. Examples include the Mid-Atlantic ridge and the East Pacific Rise. Plate separation is aslow process. For example, divergence along the Mid Atlantic ridge causes the Atlantic Ocean to widen at only about 2 centimeters per year.
Transform Boundaries
Places where plates slide past each other are called transform boundaries. Since the plates on either side of a transform boundary are merely sliding past each other and not tearing or crunching each other, transform boundaries lack the spectacular features found at convergent and divergent boundaries. Instead, transform boundaries are marked in some places by linear valleys along the boundary where rock has been ground up by the sliding. In other places, transform boundaries are marked by features like stream beds that have been split in half and the two halves have moved in opposite directions. Although transform boundaries are not marked by spectacular surface features, their sliding motion causes lots of earthquakes.