I hope this will point out a nuance that has been being passed over numerous times. As scientists learned more about seafloor spreading and magnetic reversals, they formed a theory to explain how continents move. It is a theory that truly has the entire world as its experiment. By combining the sea floor spreading theory with continental drift and information on global seismicity, the new theory of. Students will be able to understand key concepts of plate tectonics state three types of tectonic plate boundaries. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. Plate tectonics describes the distribution and motion of the 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.
Tuzo wilson put missing puzzle pieces together in 1965. Plate tectonics summary the earth is made up of 3 main layers core, mantle, crust on the surface of the earth are tectonic plates that slowly move around the globe plates are made of crust and upper mantle lithosphere there are 2 types of plates there are 3 types of plate boundaries volcanoes and earthquakes are closely. Students then explore the plate tectonic theory and types of plate boundaries by watching a video and constructing a poster. Plate tectonic theory plate tectonic theory recognizes that the lithosphere is broken into plates, jigsawlike pieces of various sizes.
The structure of the earth, plate tectonics and landforms. A unifying theory what are the main tenets of plate tectonic theory. Why is plate tectonics a unifying theory of geology. Tectonic plates are composed of oceanic lithosphere and. Together, these plates constitute the lithosphere, from the greek lithos, meaning rock.
Locations of earthquakes and volcanoes show the plate boundaries and ocean floor features. Plate tectonic theory explore historical development that supports plate tectonic theory in this presentation you will. The continents are carried on some of these plates. Convergence data are shown by arrows describing direction and speed, relative to the plate across the boundary. Show students how plate tectonic principles were deduced over hundreds of years, starting with european exploration of africa and the new world and advancing rapidly in the late twentieth century as new technologies were developed. Oceanic crust is thinner in comparison to continental crust about 8 kilometers thick.
Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. Crust is continuously being regenerated and removed. This missing piece of the puzzle helped put it all together into one theory plate tectonics. The earths crust and part of the upper mantle are broken into sections, called plates which move on a plasticlike layer of the mantle. Plate tectonics simple english wikipedia, the free encyclopedia. The following pdf produced by iris provides and excellent overview of the. Details major plates and how the theory helps predicts earthquakes. Wegeners theory and sea floor maps were used to develop the theory of plate tectonics. Introduction to plate tectonic theory, geodesy, and vlbi. 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. Fossils and mountain ranges were his evidences alfred wegener created the idea of continental drift and wrote the origin of continents and oceans to support his idea.
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. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and. The theory has caused a revolution in the way we think about the earth. Examining plate tectonics goals introduce the basic principles of the plate tectonic theory. Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. Tectonic theory definition of tectonic theory by the free. The new model of horizontal movement of the continents was called plate tectonics. 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. The theory of plate tectonics states that earths lithosphere is broken into many piecestectonic plates that move slowly over the asthenosphere. Earthquakes, faults, and folds take place at these boundaries.
Plate tectonics, or plate movements, have changed the way geologists think about the. Dec 19, 2017 plate tectonics is the theory that earths outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. In 1967, mckenzie and parker suggested the theory of plate tectonics. Below this is a zone that slows earthquake waves because the mantle here is plastic rather than brittle. Describes the theory of plate tectonics and how the theory has changed the way geologists think about the earth. What is the driving force of plate tectonics and how does this impact earthquakes and. Tectonic theory synonyms, tectonic theory pronunciation, tectonic theory translation, english dictionary definition of tectonic theory. Plate movement is driven by convection in earths mantle. Feb 29, 2020 like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. Plate tectonic theory a brief history of plate tectonic. Plate tectonics, or plate movements, have changed the way geologists think about the earth. Since the development of the theory, geologists have had to reexamine almost every aspect of.
The lithosphere is divided into plates, some of which are very large and can be entire continents heat from the mantle is the source of energy driving plate tectonics. L1 advanced readers plate motions point out that the arrows in figure 20 show the direction of plate motion. Earths crust and upper mantle are divided into plates. 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. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface. Since the theory of plate tectonics was first introduced, how far has the tectonic plate were standing on moved. 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. Plate tectonics also enabled geologists to explain the origins of the oceanic crust and the continents. To help students to grasp the concepts, teacher should have the.
First, the supposed source of new crustal material has never been adequately explained. Tectonic plates california institute of technology. 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. His ideas have been scientifically proven as time goes on. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory. Exactly how this works is still a matter of debate.
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. Chapter 1 plate tectonics power point linkedin slideshare. Plate tectonics simple english wikipedia, the free. The plates make up earths outer shell, called the lithosphere.
Then have them reread to identify observations that the theory of plate tectonics explains. Jan 15, 2014 a model of this type is needed to support plate tectonic theory and the concept of a spreading center. Sep 17, 2009 the theory of plate tectonics explains how plates and their continents move. New crustal plate is formed at the midocean ridges 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 plates plate boundary referenced from bird, peter 2003 an updated digital model of plate boundaries. In essence, platetectonic theory is elegantly simple. Aside from all the details of plate tectonic theory explored below a couple of significant concepts come from plate tectonic theory. Theory of plate tectonics was established by alfred wegener. 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 is the surface manifestation of mantle convection.
The theory of plate tectonics geology lumen learning. According to the theory of plate tectonics, the earths crust and upper mantle are. Plate tectonic theory has developed slowly and progressively since it was developed in the 1960s. The cross section should really be curved to correspond. At the end of the lesson, students reflect and apply their new understanding of the geosphere by examining how the earths systems interact when two plates collide. Plate tectonic theory both hesss discovery and wegners continental drift theory combined into what scientists now call the plate tectonic theory. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and forms new crust that builds up midocean ridges. Plate tectonics definition of plate tectonics by merriam. Tectonic theory definition of tectonic theory by the. The crust is made up of six major plates and a number of minor ones. Each type of interaction causes a characteristic set of earth structures or tectonic features. Sep 25, 2012 plate tectonics summary the earth is made up of 3 main layers core, mantle, crust on the surface of the earth are tectonic plates that slowly move around the globe plates are made of crust and upper mantle lithosphere there are 2 types of plates there are 3 types of plate boundaries volcanoes and earthquakes are closely.
One of these is that plate tectonic processes have led to the evolution of the earth. The theory of plate tectonics explains how plates and their continents move. The evidence for such an erstwhile joining of these. Plates can include both oceanic and continental lithosphere and drift across earths surface floating on the partially molten asthenosphere. Watch this video about continental drift and the mechanism of seafloor spreading create plate tectonics. Plate tectonics is the theory that explains how large pieces of the earths outermost layer, called tectonic plates, move and change shape. Central to the theory of plate tectonics is the concept of internal rigidity of tectonic plates together with eulers theo rem, which allows us to model the relative motion of plates. Describe the three types of tectonic plate and how the processes lead to changes in earths surface features. Plate convergence vectors referenced from united states geological survey. A model of this type is needed to support plate tectonic theory and the concept of a spreading center.
A synopsis of plate tectonics james madison university. Plate tectonics, our major paradigm for how the earth works, was established in the 1960ies following decades of observational research that culminated in key discoveries such as geomagnetic reversals, midocean ridges, transform faults, and seafloor spreading. According to the generally accepted plate tectonics theory, scientists believe that earths surface is broken into a number of shifting slabs or plates, which average about 50 miles in thickness. Plate tectonics hypothesis university of washington. Plate tectonics have students team read pages 158 and 159 to. You will recall from a previous chapter that there are three. Next introduction the outer layer of the earth is broken up into a number of different plates, that are constantly moving at a very slow speed next the study of the movement of these plates has led to a. Plate tectonics information and facts national geographic. These relative plate movements may combine in varying degrees, depending on the overall plate interactions. According to the generally accepted platetectonics theory, scientists believe that earths surface is broken into a number of shifting slabs or plates, which average about 50 miles in thickness. Takehome messages earths geology is dominated by the processes of plate tectonics. The lithosphere is divided into plates, some of which are very large and can be entire continents. It was from the continental drift theory, convection current theory and the theory of seafloor spreading, the theory of plate tectonics was formulated. Plate tectonics is the theory that explains the global distribution of geological.
Development of plate tectonic theory timeline preceden. 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 concept of plate tectonics was formulated in the 1960s. Plate tectonic theory had its beginnings in 1915 when alfred wegener proposed his theory of continental drift. New crustal plate is formed at the midocean ridges and old crustal plate is destroyed at deep ocean trenches. Problems with plate tectonics speculations science forums.
The theory of plate tectonics grew out of earlier hypotheses and observations collected during exploration of the rocks of the ocean floor. Continental drift, sea floor spreading and plate tectonics. In this plate tectonic framework, large scale deformation is the local response of the lithosphere to induced stresses. Plate tectonics is the theory that explains the global distribution of geological phenomena. The theory of plate tectonic jpj flashcards quizlet. Plate tectonics, theory dealing with the dynamics of earths outer shellthe lithospherethat 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. Principally it refers to the movement and interaction of the earths lithosphere. Tuzo wilson saw that the plates were separated by large faults and that there are three 3 types of plate margins boundaries. These plates move relative to one another above a hotter, deeper, more mobile zone at average rates as great as a few inches per year. Two plates move slide laterally past each other, and no oceanic crust is created or destroyed. The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.
According to plate tectonic theory, the lithosphere is divided into rigid plates that interact with one another at their boundaries. This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and. Plate tectonics is the theory that the outer rigid layer of the earth the lithosphere is divided into about a dozen plates that move across the earths surface relative to each other, like slabs of ice on a lake click picture below for a larger version. This plate motion causes them to collide, pull apart, or scrape against each other.
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