Each plate is part of a shell on a sphere, so different parts of the plate move at different velocities. Some of the most dramatic changes in earths crust, such as earthquakes and volcanic eruptions, happen along plate bounda ries. Indeed, the notion that the entire earths surface is continually shifting has profoundly changed the way we view our world. In addition to the maps visually obvious physiographic features that relate to plate tectonics, the explanatory text gives a concise summary of how plate tectonics work. The theory of plate tectonics ppt plate tectonics mantle. 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. The theory of plate tectonics explains the formation, movement, and subduction of earths plates.
Plate tectonics evidence to takes notes, first put your title at the top of the page page number, date, toc turn your notebook sideways and use a ruler to create the chart next slide part of theory definition evidence mantle convection continental drift seafloor spreading about 3 cm about 6 cm rest of the paper about 2 cm. Plate tectonics is the surface manifestation of mantle convection, but the large contrast in viscosities between the lithosphere and the deeper mantle leads to departures from a simple boiling pot analogy. The plate tectonics theory tries to explain the movement of the earths lithosphere. Organization of the tectonic plates in the last 200myr ftp directory.
An online resource from the geological society, aimed at students aged 14 16. Scientists find evidence of diving tectonic plates on europa. As you read each paragraph, take notes about the key ideas in the. The theory of plate tectonics neshaminy school district.
Each plate moves over earths and changes position with respect to other plates. Which is the evidence supporting the theory of plate. According to the theory of plate tectonics, the continents are moving because the plates the continents sit on are moving slowly over the molten mantle of the earth. Evidence for late precambrian plate tectonics in west africa. 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. As you read each paragraph, take notes about the key ideas in. Through the use of the data visualization tool, my world gis tm, you will construct a world map containing evidence to support the theory of plate tectonics. This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and.
These smaller, broken plates form a more fluid rock surface in the mantle. The importance of slab pull and a global asthenosphere to plate. What made plate tectonics a dominant process only on earth. There are three principal types of plate boundary divergent, convergent, and transform. Plate tectonics theory, formerly known as the theory of continental drift, is well supported in geology, geography and biology. Bertelloni 2002 demonstrated that predicted motions of uniform thickness plates agree best. Plate tectonics is the theory that explains the global distribution of geological phenomena. Geologists have developed the theory of plate tectonics to explain these features. Phenomenon of plate tectonics explained by eth zurich in the left of the image is the east pacific rise which has shifted due to transform faults. From wikipedia, the free encyclopedia plate tectonics from greek, tekton builder or mason describes the large scale motions of earths lithosphere. Plate tectonics theory is taught in science classrooms around the world, but just 50 years ago it was a hotly contested theory. 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 rigid lithosphere is split into 15 major plates that slowly move on. The size of plates and scale of tectonic processes are inherently unobservable, necessitating the use of images and models in instruction.
Introduce students to the concept of continental movement and plate tectonics. Plate tectonics the original conjectures concerning plate tectonics were based on circumstantial evidence like the shapes of continents being such that they would fit well if pushed together. Since 1960, when hess revived the concept of seafloor spreading a term coined by dietz, 1961, the majority of western earth scientists has accepted plate tectonics without. The global mosaic of plates periodically reorganizes itself and new plate boundaries form while others close up. Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Plate tectonics is the unifying theory of geology and revolutionized geology. Plates move apart at divergent plate boundaries such as the oceanic. Feb 01, 2011 14 videos play all khan academy plate tectonics galaxy387 former fbi agent explains how to read body language tradecraft wired duration. After creating a base map and selecting three different lines of evidence from a builtin data library, you will make selections from the evidence in order to identify relationships among the data. We now know that, directly or indirectly, plate tectonics influences nearly all geologic processes, past and present. The outlines of the continents flanking the atlantic ocean are so similar that their correspondence was apparent as soon as accurate maps became available. Sykes, isacks, and oliver all agreed to determine the order of authorship for seismology and the new global tectonics by lot after realizing it would take the hard work of all of them to stay on the leadingedge of seismological research involving plate tectonics. This process of old crust being pulled down and remelted is called. The structure of the earth, plate tectonics and landforms.
Principally it refers to the movement and interaction of the earths lithosphere. Consider that wegener published origin of the continents and oceans in 1915 in which he laid out the circumstantial evidence that indicated the continents had once been joined, but plate tectonics was not accepted as a theory until about 1968. Fossils tell us when and where plants and animals once existed. Describe some of the events and pieces of evidence that led to the theory of plate tectonics. The outer portion of the earth is made up of about 20 distinct plates 100 km thick, which move relative to each other this motion is what causes earthquakes and makes mountain ranges plate tectonics integrates evidence from many branches of science. We cannot make a mathematical nor real model of plate tectonics. Regional plate tectonics is driven by subduction, in which slabs require 515 myr to reach the boundary between the earths upper and lower mantle.
Discuss with them how europe, africa, south america, and north america might fit together as puzzle pieces. 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. Each type of interaction causes a characteristic set of earth structures or tectonic features. Pdf evidence for late precambrian plate tectonics in. Within the framework of plate tectonics, geologists have found explanations for the geologic distribution of.
Convection currents beneath the plates drive the plates in different directions. What is a brief explanation of the plate tectonic theory. Earths degassing is driven by tectonics and volcanism. Theory provides a unified explanation of earths major surface processes.
The theory of plate tectonics states that the earths surface, the upper mantle and crust, was once made up of enormous rock plates that broke into smaller pieces approximately 300 million years ago. This shell is divided into at least 25 pieces, which are called plates. Some life rode on diverging plates, became isolated, and evolved into new species. Earths shifting tectonic plates national geographic society. Plate tectonics the tectonic plates of the world were mapped in the second half of the 20th century. Call on volunteers to tell what they know about plate tectonics.
Can tectonic models help constrain the slow carbon cycle. An internet search of the exact same question will bring up a host of correct answers and links to further reading. Remains of mesosaurus, a freshwater crocodilelike reptile that lived during the early permian between 286 and 258 million years ago, are found solely in southern africa and eastern south america. This plate motion causes them to collide, pull apart, or scrape against each other. Today, we have a much broader set of evidence in favor of the hypothesis. The concept of plate tectonics was formulated in the 1960s. Plate tectonics, the study of such relative motions. The theory of plate tectonics ppt free download as powerpoint presentation. Earths structure and plate tectonics by brian abernethy this newsletter was created with smore, an online tool for creating beautiful newsletters for educators, nonprofits, businesses and more. Which is the evidence supporting the theory of plate tectonics. Aug 31, 2010 phenomenon of plate tectonics explained by eth zurich in the left of the image is the east pacific rise which has shifted due to transform faults.
Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig. Crust mantle core crust lithosphere plate movement the crust is broken into plates that move. It has the power to explain many phenomena, such as volcanoes and earthquakes. Study of earths magnetic record using data gathered from ironbearing minerals in rocks that have recorded the orientation of earths magnetic field at the time of their formation.
List and describe the evidence for the plate tectonics theory. The theory of plate tectonics offers a mechanism, acceptable to the physics community, that can account for the continental motions described by wegener, dutoit, and the paleomagnetists. How did the planet cool down before plate tectonics. Complete the comparecontrast table to show how plates move at the different types of plate boundaries. List and describe the evidence for the plate tectonics. Whereas the theory of plate tectonics entails that the plates move as rigid bodies, deforming exclusively along their boundaries within narrow. Geological features of divergent plate boundaries our mission is to provide a free, worldclass education to anyone, anywhere. Jul 06, 2018 an internet search of the exact same question will bring up a host of correct answers and links to further reading. Mar 21, 2020 plate tectonics, theory dealing with the dynamics of earths outer shell that revolutionized earth sciences by providing a uniform context for understanding mountainbuilding processes, volcanoes, and earthquakes as well as the evolution of earths surface and reconstructing its past continents and oceans. Continental drift, sea floor spreading and plate tectonics. According to plate tectonics, the outer part of the earth is a layer of rock about 100 kilometers thick. The theory of plate tectonics explains the relative movement of crustal plates that are juxtaposed with each other to form an interlocking pattern of plate boundaries, oceanic trenches, mountain ranges, etc.
Plate tectonics is a good example of how the science community collects evidence and then continuously tests the theory. Was the earths crust formed during the early stages of its evolution or is it the. Plate tectonics combines these older concepts continental drift by means of seafloor spreading with those of convection or a similar mechanism and polar wandering. Over time, the plates move and morph into natural land boundaries. 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. 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 think it is interesting to consider how long the plate tectonics revolution took to unfold. Create a timeline of the events leading to the theory of plate tectonics. The theory provides a working model for analyses of phenomena that scientists observe. Which of the following is a piece of evidence that supports the theory of plate tectonics. The lithosphere is broken up into seven very large continental and oceansized plates, six or seven. According to the theory of plate tectonics, the continents are moving because the plates the continents sit on are moving slowly over the molten mantle. 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.
The earths surface is made up of a series of large plates that can travel up to 2 or 3 cm per year. This course began by considering the evidence in the earths past for the existence of supercontinents and how evidence of past climates recorded in continental rocks can be used to reassemble ancient continental configurations. The theory has caused a revolution in the way we think about the earth. What is some evidence for the plate tectonics theory. Learn vocabulary, terms, and more with flashcards, games, and other study tools. In 1967, mckenzie and parker suggested the theory of plate tectonics. The theory of plate tectonics states that the earths crust is made up of large slowly moving pieces of rock called plates. The earliest references to this similarity were made in 1596 by flemish cartographer abraham ortelius and later in 1620 by the english philosopher francis. The movements of plates over millions of years resulted in the opening and closure of oceans and the formation and disassembly of continents. Modern continents hold clues to their distant past. Alternative conceptions of plate tectonics held by. Scientists found evidence from molten material, magnetic stripes, and drilling samples to back up wegeners theory.
The theory of plate tectonics explains the earths crustal dynamics by the movement of rigid lithospheric plates. Continental drift and plate tectonics university of iceland. Scientists have found evidence of plate tectonics on jupiters moon europa. Plate tectonics the unifying concept of the earth sciences. Plate tectonics development of tectonic theory britannica. Because of these plates, the earths crust has changed over time and is. Plate tectonics plate tectonics development of tectonic theory. Since the theory of plate tectonics was first introduced, how far has the tectonic plate were standing on moved. That said, here are some of the namesterms of the key pieces of evidence without great explanation, so people can go and research. This conceptual illustration of the subduction process where one plate is forced under another shows how a cold, brittle, outer portion of europas 2030 kilometerthick roughly 1020 mile ice shell moved into the warmer shell interior and was ultimately subsumed. Plate tectonics is the theory used to explain the structure of the earths crust and many of the associated phenomenon. Since the development of the theory, geologists have had to reexamine almost every aspect of geology. What evidence did scientists find in the himalayas that support the theory of plate tectonics.
When one plate dives under another plate, earthquakes can result and can form. We have a hypothesis of the general mechanics, but there might be pieces of data that do not fit the overall principle. The theory encompasses the older concepts of continental drift, developed. Plate tectonics the earths crust is divided into plates which are moved in various directions. Tectonic plate s, the massive slabs of earths lithosphere that help define our continent s and ocean, are constantly on the move. Learn how the theory of plate tectonics has developed, what happens at different plate margins, and the tectonic history of the uk. The plates are mobile, moving in constant, slow motion measured in rates of centimeters per year. The earth surface has continuously been changing ever since it was formed, especially regarding the geomorphological and geological phenomena. Plate boundaries may be in the middle of an ocean basin, around the edges of continents, or even within continents. A plate tectonic model for the paleozoic and mesozoic.