In 1967, mckenzie and parker suggested the theory of plate tectonics. Plate tectonic theory observing convection currents convection currents are the major driving force behind the movement of tectonic plates. Central to the theory of plate tectonics is the concept of. This graphic organizer for plate tectonic theory is a great way for students to organize their notes. 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 pictures show continental drift theory from 225 million years to present. Observations that led to the development of plate tectonic theory. Theory of continental drift proposed by alfred wegener in 1912, but not widely accepted until seafloor spreading was discovered in 1960. Using the online resources at the earthquakes living lab, students examine information and gather evidence supporting the theory. The lithosphere includes both the crust and the solid part of the. 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. Plate tectonics it was from the continental drift theory, convection current theory and the theory of seafloor spreading, the theory of plate tectonics was formulated.
Large pieces of the lithosphere that float on the asthenosphere are called. Each major piece of cracked crust is called a tectonic plate figure 22. Each province is a piece of californias tectonic jigsaw puzzle. Plate tectonics is a theory developed in the late 1960s, to explain how. Continental drift, sea floor spreading and plate tectonics. Demonstrating the movement of the earths crust and how tectonic plates interact at plate boundaries the theory of plate tectonics. Tectonic plates are composed of oceanic lithosphere and. Tectonic theories attempt to explain why mountains, earthquakes, and. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface. The crust is made up of six major plates and a number of minor ones. 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.
The following overview of plate tectonics provides a view of the big picture of californias geologic heritage. Plate tectonic theory recognizes that the lithosphere is broken into plates, jigsaw like pieces of various sizes. This plate motion causes them to collide, pull apart, or scrape. The theory of plate tectonics activityworksheet 3 volcanoes 8. The theory encompasses the older concepts of continental drift, developed. The theory of plate tectonics understanding main ideas label each. Continental drift, in the context of the modern theory of plate tectonics, is explained by the movement of lithospheric plates over the asthenosphere the molten, ductile, upper portion of the earths mantle. 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.
Earths surface is made up of rigid slabs of rock, or plates, which move with respect to each other constant motion tectonic. Plates can include both oceanic and continental lithosphere and drift across earths surface floating on the partially molten asthenosphere. Kings 1969b tectonic map of north america was on the basis of geosynclinal theory. Convection current theory cct convection current theory forms the basis of sfst and pt. The theory of plate tectonics explains how plates and their continents move. Wegeners theory and sea floor maps were used to develop the theory of plate tectonics. The plates are mobile, moving in constant, slow motion measured in rates of centimeters per year.
That map appeared in print after publication of wilsons 1965 seminal work on transform faults. Plate tectonics conclusion plate tectonics is the grand, unifying theory of earth sciences, combining the concepts of continental drift and seafloor spreading into one holistic theory that explains many of the major structural features of the earths surface. Geologists use this word to describe the forces that shape earths surface and the rock structures that form as a result. The lithosphere is broken up into seven very large continental and oceansized plates, six or seven mediumsized regional. The theory of plate tectonics geology lumen learning. From continental drift to plate tectonics 7 and therefore they could not sink to become ocean basins. The theory of plate tectonics grew out of earlier hypotheses and observations collected during exploration of the rocks of the ocean floor. 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. Plate tectonics by combining the sea floor spreading theory with continental drift and information on global seismicity, the new theory of plate tectonics became a coherent theory to explain crustal movements. Together, these plates constitute the lithosphere, from the greek lithos, meaning rock. Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig. Looking at the information you compiled in your chart above, explain one way the theory of plate tectonics can relate to engineering.
Plate tectonics the tectonic plates of the world were mapped in the second half of the 20th century. Plate tectonics describes the distribution and motion of the plates. Plate tectonics is the theory that explains the global distribution of geological phenomena. Then have them reread to identify observations that the theory of plate tectonics explains. The earths crust is divided into plates which are moved in various directions.
You will recall from a previous chapter that there are three. The continents are carried on some of these plates. 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. Earths geography has changed through time and continues to change today. The earth surface has continuously been changing ever since it was formed, especially regarding the geomorphological and geological phenomena. Principally it refers to the movement and interaction of the earths lithosphere. They also look at how volcanoes and earthquakes are explained by tectonic plate movement, and how engineers use this information. The theory of plate tectonics proposes that the lithosphere is divided into a series of plates that fit together like the pieces of a jigsaw puzzle. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. Revival of the continental drift theory wegeners theory just would not go away, despite. 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.
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 information and facts national geographic. To help your child visualize the convection process that drives tectonic plate motion, try doing this simple experiment together. Each type of interaction causes a characteristic set of earth structures or tectonic features. Plate tectonics is the movement of lithospheric plates relative to each other. This plate motion causes them to collide, pull apart, or scrape against each other.
A middle school lesson on plate tectonics theory for grades 68. New crustal plate is formed at the midocean ridges and. These plates move relative to one another above a hotter, deeper, more mobile zone at average rates as great as a. Midocean ridges are essentially submerged mountain chains that are characterised by a deep central rift valley. Continental drift theory continental drift is the hypothesis that all the continents had once been joined together in a single landmass.
Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. Third, and most fundamental, physicists discovered radiogenic heat, which contradicted the basic assumption. L1 advanced readers plate motions point out that the arrows in figure 20 show the direction of plate motion. The concept of plate tectonics was formulated in the 1960s. This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and. The lithosphere is broken up into what are called tectonic plates in the.
The theory has caused a revolution in the way we think about the earth. In the theory of plate tectonics, the earths crust is broken into plates that move around relative to each other. This was the time when reptiles and winged insects first appeared. Plate tectonic theory arose out of the hypothesis of continental drift. Since the development of the theory, geologists have had to reexamine almost every aspect of. First, the topography of the ocean floor was mapped in great detail during and after world war ii. Ocean basinsoceanic crust are continually being created and destroyed through tectonic processes. First, gather a bottle of food coloring and a large, clear glass container. The following website contains a more detailed and lesson plans on plate tectonics, geodesy, and vlbi. As a result of this movement, three types of plate boundaries are formed. Plate tectonic concepts made all earlier tectonic maps obsolete. Plate tectonic theory had its beginnings in 1915 when alfred wegener proposed his theory of continental drift. Plate tectonics the earths crust is divided into plates which are moved in various directions.
Plate tectonicsthe unifying theory of geology geology. Plates are composed of lithosphere, about 100 km thick, that float on the ductile asthenosphere. Plate tectonics have students team read pages 158 and 159 to. From wikipedia, the free encyclopedia plate tectonics from greek, tekton builder or mason describes the large scale motions of earths lithosphere. Development of plate tectonic theory timeline preceden. Introduction to plate tectonic theory, geodesy, and vlbi. Plate tectonics overview the earths crust is cracked like the shell of a hardboiled egg.
The structure of the earth, plate tectonics and landforms. The new model of horizontal movement of the continents was called plate tectonics. The theory of plate tectonics links earths internal processes to the distribution of continents and oceans. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and. Ret 2006, rev 2 7 introduction to plate tectonic theory, geodesy, and vlbi the plate tectonic theory is a relatively new, accepted only around 50 years ago. The theory of plate tectonics worksheet teachengineering. Students gather evidence to explain the theory of plate tectonics. The earth is the only planet known to currently have plate tectonics. Working in pairs, students think like engineers and connect what they. Continental drift and plate tectonics university of iceland. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory. Two scientific advances in the mid20th century resulted in information critical to acceptance of continental drift and plate tectonic theory. Continental drift theory alfred wegener, 1922 plate tectonics breakup of pangea. Chapter 1 plate tectonics power point linkedin slideshare.
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. Plate tectonic theory plate tectonic theory recognizes that the lithosphere is broken into plates, jigsawlike pieces of various sizes. In essence, platetectonic theory is elegantly simple. The theory of plate tectonics continued introduction 1.
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