The theory of plate tectonics hilldale public schools. The earth is composed of layers of different composition and physical properties, principally the solid central core, the fluid peripheral core, the viscous mantle, and the solid. Plate tectonics theory, convection currents and seafloor. Plate tectonics theory, convection currents and seafloor spreading. Jan 15, 2014 according to plate tectonic theory, plates are moving away perpendicularly from a spreading center. The idea that the earths crust is made up of huge tectonic plates that are floating on. Modern continents hold clues to their distant past. Lithosphere is divided into plates that slide around on top of the slowly moving mesosphere tectonic plates it occurred after the breakup of pangaea, and since then the continents have drifted apart. The geological evidence collectively provides enormous weight to the theory of. Jun 11, 2009 granted, there is a lot more missing from the theory of plate tectonics than from the theory of evolution, but the treatment is essentially the same. Explain how scientists measure the rate at which tectonic plates move. Plate tectonics theory is taught in science classrooms around the world, but just 50 years ago it was a hotly contested theory. An internet search of the exact same question will bring up a host of correct answers and links to further reading.
Therefore, the distance between overlapping segments must be increasing. Plate tectonics from the late latin tectonicus, from. Frank taylor first proposed this idea in 1910, alexander du toit later in 1937, harry hess explored the geomorphology of the seafloor by ship in 1960s. Pdf the main problems of the plate tectonics model are discussed in the paper. Plate tectonics, volcanoes and earthquakes science learning hub. However, the overlapping regions are always near each other. As the tectonic plates move away from spreading zones, they collide with one another. The concept of plate tectonics was formulated in the 1960s.
According to the theory of plate tectonics, the earths lithosphere is broken into distinct plates which are floating on a ductile layer called asthenosphere upper part of the mantle. What are the limitations of the plate tectonic theory. When the earth originated it contained no continents, and consisted of only a few kinds of igneous rock roughly the. These relative plate movements may combine in varying degrees, depending on the overall plate. They are mantle convection, gravity, and the earths rotation. List and describe the evidence for the plate tectonics theory. Continental drift, sea floor spreading and plate tectonics plate tectonics is a theory developed in the late 1960s, to explain how the outer layers of the earth move and deform. Then have them reread to identify observations that the theory of plate tectonics explains. According to plate tectonic theory, plates are moving away perpendicularly from a spreading center. Mechanics of plate tectonics by danielle parker on prezi. Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. Using the theory, we know where new ocean floor will be created and where it will be destroyed. Plate tectonic theory both hesss discovery and wegners continental drift theory combined into what scientists now call the plate tectonic theory. Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig.
The theory of plate tectonics geology lumen learning. One of these is that plate tectonic processes have led to the evolution of the earth. The basic theory of plate tectonics is that along seafloor spreading zones, the continents are separating from one another. Plate tectonics studentled station lab distance learning. Describe the three forces thought to move tectonic plates. Tectonic theory definition of tectonic theory by the. Mantle convection is the most widely studied method of tectonic plate movement and it is very similar to the theory developed by holmes in 1929. It is theorized that the hotter rock closer to the core rises while the cooler rock sinks causing a current in the form of a cycle. Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Granted, there is a lot more missing from the theory of plate tectonics than from the theory of evolution, but the treatment is essentially the same. Introduction to plate tectonic theory, geodesy, and vlbi.
Plate tectonics, theory dealing with the dynamics of earths outer shell that revolutionized earth sciences by providing a uniform context for understanding. In 1912, wegener noticed that the coastlines of the east coast of south america and the west coast of africa seemed to fit together like a jigsaw puzzle. The presentday theory of plate tectonics contains seven significant errors of logic that when taken together render the theory unworkable. Plate tectonics studentled station lab distance learning plate tectonics station lab students will love you for providing them with a handson experience when learning about tectonic plates.
Plate tectonics grew out of a theory that was first developed in the early 20th century by the meteorologist alfred wegener. Mechanics of plate tectonics understanding plate tectonic theory read the article and answer the following questions in complete sentences. Tectonic theory synonyms, tectonic theory pronunciation, tectonic theory translation, english dictionary definition of tectonic theory. In the theory of plate tectonics the outermost part of the earths interior is made up of two layers, the outer lithosphere and the inner asthenosphere the lithosphere essentially floats on the. As they spread apart, magma comes to the surface and becomes new continental crust. The earth is the only planet known to currently have plate tectonics. While the lateral extent of modern plate can be easily defined by earthquake activity, its thickness is not physically defined. Plate tectonic theory observing convection currents convection currents are the major driving force behind the movement of tectonic plates. His continental drift theory was the first step in the development of plate tectonic theory, the foundation upon which modern geology is built. The cross section should really be curved to correspond.
The convection driving the crust formation might be a. At an average rate of 33 feet per 100 years about 10 cmyear, a tectonic plate can move 62. In 1912, wegener noticed that the coastlines of the east coast of south america and the west. To help your child visualize the convection process that drives tectonic plate motion, try doing this simple experiment together. The latitudinal shift from tpw would combine with the reduced plume. Alfred wegener, a german meteorologist born in 1880, developed the idea of continental drift. Plate tectonic theory had its beginnings in 1915 when alfred wegener proposed his theory of continental drift. The motion in the mantle the asthenosphere is caused by convection currents. Plate tectonics is the theory that explains the global distribution of geological phenomena. In essence, platetectonic theory is elegantly simple. Tectonic plates are able to move because the earths. Problems with plate tectonics speculations science forums. L1 advanced readers plate motions point out that the arrows in figure 20 show the direction of plate motion. Aside from all the details of plate tectonic theory explored below a couple of significant concepts come from plate tectonic theory.
This module describes how the work of alfred wegener, harry hess, and others led to our understanding of plate tectonics. A unifying theory what are the main tenets of plate tectonic theory. The earths surface is made up of a series of large plates that can travel up to 2 or 3 cm per year. Theory of sea floor spreading hot, less dense material below the earths crust rises toward the surface at the midocean ridges. Since the development of the theory, geologists have had to reexamine almost every aspect of. It may be fantastic, but that is exactly what is happening. Plate tectonic theory suggests that the earths surface consists of huge plates of crustal rock that are forming, moving, and colliding. Against plate tectonics on earth the plate tectonics theory. Fossils tell us when and where plants and animals once existed. It was from the continental drift theory, convection current theory and the theory of seafloor spreading, the theory of plate tectonics was formulated.
Since the theory of plate tectonics was first introduced, how far has the tectonic plate were standing on moved. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface. Central to the theory of plate tectonics is the concept of. Convection currents beneath the plates drive the plates in different directions. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. The crust is formed at a spreading center that is poorly developed but sufficient to introduce new crust to the floor of the backarc. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory. Jan 23, 2020 there are three main driving forces for the movement of the earths tectonic plates. Plate tectonics is the theory that the outer rigid layer of the earth the lithosphere is divided into a couple of dozen plates that move around across the earths surface relative to each other, like slabs of ice on a lake. Plate tectonics have students team read pages 158 and 159 to.
The theory of continental drift was the first step toward plate tectonic theory, which became the foundation upon which modern geology is built. The currents would be at parts parallel to giant plates on the surface and carry them. This is a bold statement given the general acceptance of this theory. This pdfversion was edited by peter lindeberg in december 2001. Which is the evidence supporting the theory of plate. Fellow scientists at the time thought the theory was ludicrous. Plate tectonics theory states that the earths surface is an interlocking. That said, here are some of the namesterms of the key pieces of evidence without great explanation, so people can go and research. Some life rode on diverging plates, became isolated, and evolved into new species.
First, gather a bottle of food coloring and a large, clear glass container. When alfred wegener first proposed the idea of continental drift the precursor idea to plate tectonic theory, it didnt quite explain the full story. Why is plate tectonics a unifying theory of geology. One defining feature of modern plate tectonics is the differential horizontal. It is very well supported theory, and while scientific debate continues about small parts or local effects, the overall concept is accepted as good as fact. Paleomagnetic evidence for modernlike plate motion velocities at. What are the clues and evidences to support the theory. This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and. Together, these plates constitute the lithosphere, from the greek lithos, meaning rock. The earths crust and part of the upper mantle are broken into sections, called plates which move on a plasticlike layer of the mantle. What are the three types of plate boundaries and relative motion at the boundaries. The earths crust is broken into a dozen or so large plates that move over the earth interacting in three ways. He suggested that continents moved around the earth like giant rafts. Chapter 1 from continental drift to plate tectonics naomi oreskes since the l6th century, cartographers have noticed the jigsawpuzzle fit of the continental edges.
Wegener proposed that the continents plowed through crust of ocean basins, which would explain why the outlines of many coastlines like south america and africa look like they fit together like a puzzle. The seven enigmas of plate tectonics pangaea theory. From almost the creation of the first true maps of the earth, people started. Plate tectonics helps us to understand where and why mountains form. A synopsis of plate tectonics james madison university. The plate tectonics theory tries to explain the movement of the earths lithosphere. The lithosphere is broken up into seven very large continental and oceansized plates, six or seven mediumsized regional. Plate tectonics is the theory used to explain the structure of the earths crust and many of the associated phenomenon. What evidence did scientists find in the himalayas that support the theory of plate tectonics. In the theory of plate tectonics the outermost part of the earth s interior is made up of two layers, the outer lithosphere and the inner asthenosphere.
Like the scientists before us, we will now merge the ideas of continental drift and. When the earth originated it contained no continents, and consisted of only a few kinds of igneous rock roughly the composition of the moon. Tectonic theory definition of tectonic theory by the free. Two plates move slide laterally past each other, and no oceanic crust is created or destroyed. Explain continental drift, including the history and controversy behind it. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This lack of definition makes it difficult to understand how plates move. The idea that the earths crust is made up of huge tectonic plates that are floating on an ocean of molten hot magma seemed too fantastic to be believed. The physiography and composition of earths modern crust bear evidence for plate tectonic or.
Plate tectonics is the theory that explains the global distribution of geological. Pdf critical analysis of the plate tectonics model and causes of. Alfred wegener and continental drift it was not until 1912 that the idea of moving continents was seriously considered as a fullblown scientific theory called continental drift introduced in two articles published by a 32yearold german meteorologist named alfred lothar wegener alfred lothar wegener 18801930 earned a. The theory of plate tectonics explains most of the features of earths surface. In this plate tectonic framework, large scale deformation is the local response of the lithosphere to induced stresses. Earths surface layer, 50 to 100 km 30 to 60 miles thick, is rigid and is composed of a set of large and small plates. Origins of plate tectonic theory earth science visionlearning.
In 1967, mckenzie and parker suggested the theory of plate tectonics. The current theory is that the plates are moved around by convection currents caused by the cooling of the core and radioactivity of the molten magma below the plates. Tectonic plates move at rates that vary from less than 6 feet per 100 years to 66 feet per 100 years 1. The theory of plate tectonics links earths internal processes to the distribution of continents and oceans. Jul 06, 2018 an internet search of the exact same question will bring up a host of correct answers and links to further reading.
The theory of plate tectonics objectives describe the three types of tectonic plate boundaries. Plate tectonics is a theory of geology developed to explain the phenomenon of continental drift, and is currently the theory accepted by the vast majority of scientists working in this area. There are three main driving forces for the movement of the earths tectonic plates. Critique and interpret major types of evidence supporting the theory of plate. Continental drift, sea floor spreading and plate tectonics. Then it flows sideways, carrying the seafloor away from the ridge in both directions as distance from the ridge increases, the age of the seafloor increases. The theory has caused a revolution in the way we think about the earth.
Principally it refers to the movement and interaction of the earths lithosphere. While he correctly showed that africa and south america fitted together, his model wasnt able to explain the violent forces that occur around the earths crust. Thin viscous sheet theory is born of a belief that plate tectonic theory, originally conceived of at the global scale, doesnt adequately explain the smallerscale motions of continents. The station lab is a plug and play unit that is meant to accompany my free kesler science station lab series. According to the theory, earth has a rigid outer layer, known as the lithosphere, which is typically about 100 km 60 miles thick and overlies a plastic moldable, partially molten layer called the asthenosphere. I hope this will point out a nuance that has been being passed over numerous times. The evidence for plate tectonics is very conclusive.
By working in research groups investigating different but related ideas, students will experience the value of sharing results, and recognise the ways that scientists develop increasing confidence in a common. The plates are mobile, moving in constant, slow motion measured in rates of centimeters per year. The following pdf produced by iris provides and excellent overview of the. Developed from the 1950s through the 1970s, plate tectonics is the modern version of continental drift, a theory first proposed by scientist alfred wegener in 1912. Scientists found evidence from molten material, magnetic stripes, and drilling samples to back up wegeners theory.