Plate Tectonics Project
Hayley Verhoev - Period 7
What is Plate Tectonics?
Plate tectonics was a theory explaining the structure of the earth's crust with 12 plates that move slowly over the underlying mantle. In the early 1900's, there was a theory that all the plates were once all together. This was called Pangaea.
Pangaea Before And After
The 3 Types Of Boundaries
When 2 plates slide past each other fast and suddenly causing Earthquakes.
When 2 plates move away from each other causing earthquakes, volcanoes and sea floor spreading.
When 2 plates with the same density collide with each other and push against each other. This causes folded mountain ranges.
The Layers Of The Earh
The core is made primarily of iron and nickel and has two parts — an inner solid core and an outer liquid core.
The mantle is one of the three main layers of the Earth. It lies between the innermost layer, the core, and the thin outermost layer, the crust. The mantle consists of hot, dense, semisolid rock.
The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.
The 12 Plates
Plate Tectonics Questions And Answers
-What are the three layers of the Earth and why each layer is important.
The crust is important because it’s the layer we live on. It’s what supports our life on Earth. Without it we wouldn’t survive. The mantle is important because it’s what helps move the plates. The mantle is where the convection currents are located. The core is important, because the iron and nickel in the outer core create our magnetic field. Without the magnetic field to create our magnetosphere, all life on Earth would be burned by the Sun and its explosive rays.
-Explain continental drift.
Continental drift is movement of the plates over the Earth’s surface over time.
-Research who created the hypothesis for continental drift.
The theory was first created by Abraham Ortelius in 1596 and was later fully developed by Alfred Wegener in 1912. He first published this is a book, talking about his theory and Pangaea. It wasn’t until the 1960’s until people started to notice that the continents seem to fit together in some way.
-What evidence (2 types) did scientists use to prove continental drift? Explain.
The first one is fossils. A scientist noticed that there were 2 fossils of the exact same animal but one was from South America and the other from Africa. The second theory is that Earth's crust slowly drifts atop a liquid core proving that the continents could drift apart.
-Explain sea-floor spreading.
When two plates move away from each other, they create a gap in between them. Magma from beneath it rises up. It cools and then creates new land and the process is started over again.
-Who discovered sea-floor spreading?
Harry Hess discovered the theory for sea floor spreading. It started by having a theory that the sea floor was also warmer near the mid- Atlantic ridge, but it was actually just heat from the magma underneath it. Later, this is how sea floor spreading was discovered.
-How does sea-floor spreading help scientists to explain continental drift?
Sea floor spreading occurs at mid- Atlantic ridges and how when plates move apart magma fills in the gap and forms new land. This helped the theory of continental drift because it showed the plates can move apart.
-Explain how convection helps with plate movement.
Convection currents are located in the mantle. Convection is when warm air rises and cold air falls. The plates sit over the mantle and also the convection currents. The plates can move away or toward each other because of the way the convection currents are located.
-What is the theory of plate tectonics?
The theory is that the outer layer of the Earth has twelve different plates that move slowly across the Earth’s surface. The plates are all relatively close to one another, and once all fitted together.
-Describe the types of boundaries that exist.
Transform Boundary: This is when two plates rub against each other or slide past each other in a sudden movement. This usually happens along fault lines, like the San Andreas Fault, and when this happens it causes earthquakes.
Divergent Boundary: This is when two plates move away from each other. There are two types of Divergent boundary, oceanic and continental. Both of these cause earthquakes and volcanoes but aren’t as likely
Convergent Boundary: This is when two plates collide with each other. In order for it to be convergent both plates have to have an equal amount of density. Convergent boundaries can form folded mountain ranges. An example would be the Himalayas Mountains. Both plates collided with equal density causing it to be pushed upward.
Convergent with Subduction: This is when a continental plate and an oceanic plate collide and one plate, one with less density, goes under the other plate. Most of the time the oceanic plate goes below the continental plate. This can form trenches and volcanoes. The most famous trench is Marianas Trench. Also, Hawaii has a lot of active volcanoes because of this.
-Explain the significance of the ring of fire.
The Ring of Fire is an area where a large number of earthquakes and volcanic eruptions occur in the Pacific Ocean. One important thing from the ring of fire is the magma. The magma, combined with water, metals, rock and heat, are used to create islands.
-Describe the type of geological features and natural disasters that can occur at the three types of plate boundaries.
At Transform boundaries, there can be major or small fault lines, and also earthquakes. Transform boundaries are characterized by their earthquakes, since transform boundaries can have the most powerful earthquakes. At convergent boundaries, there can be folded mountain ranges when 2 plates with equal density collide. These can cause mountains, like the Himalayas. Convergent with subduction is the movement of oceanic crust beneath a continental plate results in making trenches and volcanoes. The resulting magma moves upward towards the surface of the plate boundary forming volcanic eruptions. At divergent boundaries, they are characterized by a rift in the surface of the earth along the mid-ocean ridges that exist in all of the major oceans. The ridges are composed of volcanic mountains that erupt onto the surface of the ocean and by that process create new oceanic crust.