PLATE TECTONICS ESSAY
Cole Carpenter
Sacred Heart Academy
In the early 20th century there was a theory called Contracting Earth theory. It stated that the Earth was completely molten, and then as time passed it slowly cooled. As the Earth cooled it caused contraction and tons of pressure. This made the mountains and oceans. This theory is wrong because it doesn’t explain puzzle piece continents. Even though the contracting earth theory is in opposition to the plate tectonic theory, plate tectonic theory has much more evidence like continental drift, seafloor spreading, and also volcanic and seismic evidence (Richardson, 2014).
Continental drift has led to the development of the plate tectonics theory. It was introduced in 1912. Continental
…show more content…
Overtime as this new ocean floor gets created new bodies of water and even new and land. Harry Hess was one of the main creators of the sea floor spreading theory. Hess was a geologist and helped navy seals to determine depths on oceans. Harry Hess used bathymetric maps (maps that shows scans of oceans and the land around it) to help determine ocean depths. Harry used these maps to prove the theory of sea floor spreading. Scientists found another theory to back up sea floor spreading. This would be magnetic evidence. Scientists found as the molten rock cooled and turned into rock, the iron in the rocks lined up to the earth’s magnetic poles. Scientists used a magnetometer (an instrument used to find and measure magnetic forces) to help find this evidence. This supports the theory by providing mechanisms for sea floor spreading (Feather, Hesser, & Snyder, 1995). Some of the latest key evidence to back up plate tectonics is recent volcanic and seismic findings. The gathering of volcanic and seismic data is some of the latest key evidence for the theory of plate tectonics. Volcanoes are located at subduction plate boundaries, divergent boundaries, and hot spots. Subduction is when one plate moves over another, which forms a volcano. Earthquakes are located at any plate boundaries (Feather, Hesser, & Snyder, 1995). Earthquakes are made when two plates get caught up against each other while trying to slide past each other. All of the plates’ energy gets released violently in the form of an
15. The pictures above show how the continents on Earth’s surface have changed position over a very long period of time. What explains this change? (S6E5e, f)
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
The earth is split into four layers, inner and outer core, the mantle and crust. The top of the mantle and crust make up what is like the skin of our earth (see source 2). The skin is split up like a puzzle and we call these puzzle pieces’ tectonic plates (see source 1). These plates are constantly moving and the plate boundaries (edges of the plates) move and slide past one another. Sometimes as the plates move the plate boundaries become stuck. Pressure builds up in the stuck area over time and eventually breaks. This is why earthquakes occur due to the sudden movement of the plate sliding and breaking creating a fault line to go off. The fault line is the line on which the
Seismic studies show that the mid-oceanic ridges experience an elevated number of earthquakes. All these observations indicate intense geological activity at the mid-oceanic ridges. Periodically, the Earth's magnetic field reverses. New rock formed from magma records the orientation of Earth's magnetic field at the time the magma cools. Study of the sea floor with magnetometers revealed "stripes" of alternating magnetisation parallel to the mid-oceanic ridges.
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.
Mauna Loa is located on a hot spot in the Pacific Ocean. It is not near a plate boundary, in fact it is 3,200 km from the nearest plate boundary, and is situated in the middle of the Pacific tectonic plate. This is actually a rarity, as 90% of volcanoes are along a tectonic plate boundary. A hot spot occurs where long, stationary vertical pools of magma rise up and towards the plate. Movement of the tectonic plates above the hot spot created Mauna Loa, along with the other Hawaiian volcanoes. The older Hawaiian Islands were once above this stationary hot spot, but have been carried northwest by the slowly moving Pacific plate. As the plate moves, it carries the previously formed, older, volcanoes with it, creating a trail of younger, new volcanoes behind. The islands are lined up along the Hawaiian Ridge-Emperor Seamounts chain, which is 3,750 miles and includes Kauai, Maui, Oahu and Hawai’i, from north to south, respectively. There are around 80 volcanoes in this chain; most of them underwater, consequently the term seamount refer to submarine volcanoes. Three volcanoes of Hawai’i, Mauna Loa, Kilauea and Loihi seamount, are all currently sharing the Hawaiian hot spot. Although, recent evidence has shown that all three volcanoes use have separate plumbing systems to expel the lava from the pool of magma deep below them. It has also been suggested that Loihi is slowly moving Mauna Loa from the center of the island, thus shifting directly over the hot spot. The closer to the hot spot a volcano is, the more active it will be. The Hawaiian hot spot has laid down layers of lava, building up enormous islands from the ocean floor.
Palaeogeography deals with the reconstruction of physical geographical conditions for the eras of the Earth's history. The term comes from the Greek παλαιός (palaiós) meaning ‘old’ and γεωγραφία (geōgraphía) meaning ‘a description of the earth’ and seems to have been introduced in the Earth sciences vocabulary as ‘Palaeo-Geographie’ by Ami Boué (1794‒1881), a French‒Austrian geologist, in his publication Einiges zur palaeo-geologischen Geographie (Boué, 1875, p. 2). Palaeogeography focuses on the distribution of land and sea, the spread of mountains and volcanoes and the expansion of glaciations, among others. The results are presented in geographic depictions called palaeogeographic maps. A special kind of palaeogeograpahical map is palaeobiogeographical maps depicting the distribution of
In the central area of the Pacific Ocean lies the Hawaiian Islands spanning 2,400 kilometers long beginning at Kure Island, located in the northwest to big island of Hawaii (Edge of Fire). This island is 3,000 kilometers away from the nearest continent, which is North America. The creation of the islands today came from “Hotspots”, which are characterized as plumes of magma rising from the mantle of the Earth through the continental crust, creating huge shield volcanos which contribute to the land mass that subsequently gets created. With the help of divergent (creation) and convergent (destruction) zones, the Earth’s crust eventually moves the newly created landmass off the Hot Spot plume, effectively rendering the volcano extinct, and allowing for new land to be created over the still stationary (and active) plume in the mantle.
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 west coast of the islands is on the edge of a continental shelf created by ancient volcanic movement (Broadhead 5) .This volcanic activity is due to plate tectonic movement which also created the numerous amounts of earthquakes on the island. Compared to the rest of British Columbia, Haida Gwaii has the most earthquake activity (Broadhead 5), the last of which being in a magnitude of 7.7 on t...
First you might need to know definition of tectonics. It is a theory in geology. The lithosphere of the Earth is divided into a small number of plates which float on and travel independently over the mantle and much of the Earth’s seismic activity occurs at the boundaries of these plates. That is the official definition of Plate tectonics. secondly, this plate covers many parts of continents. plate boundaries don’t go according to Continents boundaries, they make their own boundaries. The North American plat...
Although geographers don’t all agree on one theory as to why the ice ages may have happened, there are a couple theories that many believe could have caused the beginning of the ice ages. One of the leading theories for the cause for ice age involves the idea of another theory, the plate tectonics theory, which proposes that the Earth’s surface, which are divided into plates, are constantly moving. The theory suggests that the plates of the Earth moved away from the equator where it is generally warm, and towards a colder place, an area where the sun’s rays were not very strong, which made land very cold. This is a logical theory be...
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 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).