Assignment: Sources of Plate Motion Exploration
Introduction
Recall that scientists think gravity acting on the edges of tectonic plates is a factor in their movement. These effects are called ridge push and slab pull. You can model these effects with a chair and a bed.
Ridge push
If you sit on a chair and let gravity pull you down into a slouching position, you'll notice your legs move out away from the chair. When your upper body falls down, it pushes your legs out and away, just as the ridge of a tectonic plate falling down pushes on the other end of the plate. The other end of the plate moves out and away from the pushing part of the plate.
Slab pull
Lie on a bed facing down with your upper body hanging just a little over the edge. Slowly and
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Describe what occurs at mid-ocean ridges.
A mid-ocean ridge is a mountain range under the water. It is formed due to plate tectonics. The shifting of the plates lifts up the floor of the ocean. When convection currents occur they raise the mantle that is located beneath the oceans crust and it creates magma where the two tectonic plates meet.
Study this map that shows the motion of the Earth's plates.
5. Find the Nazca plate and the South American plate. How are they different? Are they moving toward or away from each other?
The Nazca plate is an oceanic plate, while South American plate is continental. The Nazca is moving East towards the South American plate at a downward angle and converging. This process is called subduction, resulting in a lot of earthquakes and production of the Andes Mountains.
6. List the kinds of features you might expect to see near the edges of plates, like these two plates that are coming together.
Some features you may expect to see at the site where two plates converge, or a convergent boundary, would be mountains and volcanoes. It may even form a chain of volcanoes. Earthquakes are likely as well.
7. How is the Nazca plate moving in relation to the Pacific
Source 4. A map of the Earth’s fault lines and plates with the direction of their movement.
Evaluating the Evidence for Continental Drift There are several pieces of evidence certifying the existence of continental drift. They include mid oceanic ridges, fitting of continents, similarities of fossils on different continents and rock matches. The mid-oceanic ridges rise 3000 meters from the ocean floor and are more than 2000 kilometres wide surpassing the Himalayas in size. The mapping of the seafloor also revealed that these huge underwater mountain ranges have a deep trench, which bisects the length of the ridges, and in places is more than 2000 meters deep. Research into the heat flow from the ocean floor during the early 1960s revealed that the greatest heat flow was centred at the crests of these mid-oceanic ridges.
According to Levin, “This subduction created batholiths, compressional structures, volcanism, and metamorphism that accompanied Mesozoic and Cenozoic orogenies.” The dense oceanic crust was subducting beneath the continental crust more quickly than it was being created at the mid-ocean spreading ridge. The oceanic crust was part of the Farallon plate, which has now almost completely disappeared because it was consumed by the North American plate (Levin).
Island arcs form as oceanic plate subducts under oceanic plate. Volcanism is concentrated in an arc of volcanoes, generally approximately located above the leading edge of the subducting plate. A trench often forms where the slabs meet and subduction begins. On the non subducting slab a series of basins form, with a fore-arc basin nearest the subduction/trench, then the main arc, and a back-arc basin on the far side (Mitchell and Reading, 1971; Frisch, Meschede and Blakey, 2010).
... plate is now called the Juan de Fuca plate (“Juan de Fuca General”). This happened just before the Laramide orogeny contributing to the building of this huge landmass of geological features.
When the plates mash together on a convergent boundary, they can create an earthquake. A place with a convergent boundary is New Zealand. When the plates pull apart, a divergent boundary, they create a hole in the ocean that causes molten lava to rush up and it causes a volcano to form. A place with a divergent boundary is Iceland. With about 130 volcanoes all together, it has the most volcanoes of any country in the world and is on two tectonic plates. Santorini is currently in an area of earth where the African and Eurasian plate meet, and Atlantis disappeared with a rumble that could have come from a volcano or an
About 20 million years ago the last part of the Farallon sea floor plate subducted under the North American plate. This put the North American plate and the Pacific plate into contact, but unlike the Farallon sea floor plate, the Pacific plate sheared against the side of the North American plate. Because there was no plate subducting, the North American plate was in direct contact with the mantle (Tierney, 29). Heat from the mantle made the continental crust more ductile, which allowed the crust to extend and thin.
Tectonic Activity The continents of the world are all separated by different tectonic plates which when collide is called Tectonic Activity. There are different forms of tectonic activity and different processes and landforms, which are involved during and as a result of the collisions. As and when these collisions are going to take place we can't determine because current technology hasn't allowed us to dig as far into the earth to the point of pressures which causes the plates to collide. These pressures are believed to be eruptions of liquid magma deep inside the earth.
Understanding the plate tectonics theory is very important, especially when investigating natural disasters like earthquakes, and volcanic eruptions. It is also gives scientists the ability to understand how mountains were formed between two tectonic plates. There are three types of interactions between plate boundaries: convergent, divergent and transform. Looking back at the history of these three different interactions, earthquakes, like the one in Haiti, volcanic eruptions, like at Mount St. Helens, and the creation of mountain belts, like the Mid-Atlantic Oceanic ridge, gives information on future consequences of tectonic movement, and what can happen when the plates interact with each other.
Volcanism is a major part of the Galapagos and their formation. The island chain is positioned on the Nazca Plate, which is subducting beneath the South American Plate at a geologically rapid pace of 2.5 inches per year. In addition, this Nazca Plate is located directly on top of the Galapagos Hotspot. It is here that mantle plumes melt Earth’s crust, creating volcanoes as a product. The oldest island was first shaped by this ...
The Magnificent North American Tectonic Plate Even though other global problems are bigger than Plate tectonics, the North American Plate took many years to form, is very divers, and is purely magnifect because a big part of our everyday life and the plate tectonic theory is one of the oldest theories known to man. There are also many different aspects to the North American Plate. There are regular basic facts about the plates, there are specific scientists that gathered and founded information about this plate and many others. There is the location of this plate and the plates surrounding it. There are multiple different types of boundaries that surround this plate.
Convection currents deep in the mantle of the earth, begin to well up towards the surface. As the pressure increases, it sets the crustal plates in motion. There are different kinds of mountains - Volcanic, Folded, Fault-block, and Dome mountains. Volcanic mountains are formed when magma comes up through cracks in the Earth’s crust and explodes out of lava and ash. The Hawaiian volcanoes, Mt. Hood, Mt. Etna, Vesuvius, and Mt. Saint Helens is an example of volcanic mountains.
Plate tectonics is the theory that landmasses on tectonic plates are in slow constant movement due to convection currents in the mantle. Plate tectonics, or the movements of plates above the lithosphere (the most upper layer of earth's crust) can cause divergent, convergent,and transform boundaries.A boundary the way two tectonic plates collide. is Continental plates are plates that the continents are formed on. Oceanic plates are plates that the ocean covers, and the oceans form on top of these plates. Convergent boundaries and divergent boundaries are ways that these oceanic and continental plates interact with each other. Landforms are formed at boundaries. The landforms formed at boundaries depends on the type of plates that collide, and
The Pacific plate is moving northwest in relation to the North American plate, and it is believed that the total displacement along the fault since its formation more than 30 million years ago has been about 350 mi. Movement along the fault causes earthquakes; several thousand occur annually
The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3).