Theory of continental drift proposed by alfred wegener in 1912, but not widely accepted until seafloor spreading was discovered in 1960. 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. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory.
This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and. The crust is made up of six major plates and a number of minor ones. Plate tectonic theory arose out of the hypothesis of continental drift proposed by alfred wegener in 1912 6 and expanded in his 1915 book the origin of continents and oceans. This technique for showing features on the ocean floor has steadily improved since 1983. The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction. The following overview of plate tectonics provides a view of the big picture of californias geologic heritage. Plate tectonicsthe unifying theory of geology geology u. Plate tectonics the earths crust is divided into plates which are moved in various directions. Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. Earths geography has changed through time and continues to change today. Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig. 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.
Development of plate tectonic theory timeline preceden. Ocean basinsoceanic crust are continually being created and destroyed through tectonic processes. Each major piece of cracked crust is called a tectonic plate figure 22. There he argued for the separation of wegeners pangea into the two super continents, laurasia and gondwana. Perfect for whole group lessons, interactive science notebooks, or student note taking guides.
The theory of plate tectonics understanding main ideas label each. Introduction to plate tectonic theory, geodesy, and vlbi. Demonstrating the movement of the earths crust and how tectonic plates interact at plate boundaries the theory of plate tectonics. 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 a result of this movement, three types of plate boundaries are formed. The theory of plate tectonics geology lumen learning. Plate tectonics overview the earths crust is cracked like the shell of a hardboiled egg. Looking at the information you compiled in your chart above, explain one way the theory of plate tectonics can relate to engineering. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface. A quick overview of plate tectonics, including a look at the different types of plate boundaries. According to the theory of plate tectonics, the earths lithosphere is broken into distinct plates which are. The theory has caused a revolution in the way we think about the earth.
Plate tectonics is the theory that explains the global distribution of geological phenomena. Revival of the continental drift theory wegeners theory just would not go away, despite. This plate motion causes them to collide, pull apart, or scrape. Central to the theory of plate tectonics is the concept of. Two scientific advances in the mid20th century resulted in information critical to acceptance of continental drift and plate tectonic theory. In this plate tectonic framework, large scale deformation is the local response of the lithosphere to induced stresses.
You will recall from a previous chapter that there are three major layers crust, mantle, core within the earth that are. The continents are carried on some of these plates. 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 theory of plate tectonics activityworksheet 3 volcanoes 8. 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. 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. Observations that led to the development of plate tectonic theory. New crustal plate is formed at the midocean ridges and. Learn 7th grade science chapter 7 plate tectonics theory with free interactive flashcards. Tectonic theories attempt to explain why mountains, earthquakes, and. Mar 01, 2016 this video briefly discusses the theory of tectonic plates, the different types of plate boundaries and their surface features. Tectonic plates are able to move because the earths. The earth surface has continuously been changing ever since it was formed, especially regarding the geomorphological and geological phenomena. Since the development of the theory, geologists have had to reexamine almost every aspect of.
The theory of plate tectonics links earths internal processes to the distribution of continents and oceans. Tectonic plates huge pieces of lithosphere that slowly move. 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. Since the theory of plate tectonics was first introduced, how far has the tectonic plate were standing on moved. The structure of the earth, plate tectonics and landforms. 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. Each province is a piece of californias tectonic jigsaw puzzle. Each type of interaction causes a characteristic set of earth structures or tectonic features. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. The cross section should really be curved to correspond. Midocean ridges are essentially submerged mountain chains that are characterised by a deep central rift valley. In the theory of plate tectonics, the earths crust is broken into plates that move around relative to each other. Plate tectonics have students team read pages 158 and 159 to. Then have them reread to identify observations that the theory of plate tectonics explains.
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. Continental drift, sea floor spreading and plate tectonics. Plate tectonics is a theory developed in the late 1960s, to explain how. Plate tectonics describes the distribution and motion of the plates. The outer limbs of the convection cells plunge down into the deeper mantle, dragging oceanic crust as well. 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.
At divergent boundaries in the oceans, magma from deep in the earths mantle rises toward the surface and pushes apart two or more plates. He published his observations in a geological comparison of south america with south africa1927, and later he developed his ideas in our wandering continents1937. Third, and most fundamental, physicists discovered radiogenic heat, which contradicted the basic assumption of contraction theory that the earth was steadily cooling. Tectonic plates huge pieces of lithosphere that slowly move on the asthenosphere and consist of the crust and the rigid, uppermost part of the mantle. 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. Seafloor and continents move around on earths surface, but what is actually moving. In the early 1900s alfred wegener proposed the continents were drifting. This was the time when reptiles and winged insects first appeared. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and forms new crust that builds up midocean ridges. First, the topography of the ocean floor was mapped in great detail during and after world war ii. Principally it refers to the movement and interaction of the earths lithosphere. 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. Tectonic plates are composed of oceanic lithosphere and. Dec 12, 20 a quick overview of plate tectonics, including a look at the different types of plate boundaries.
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. In essence, platetectonic theory is elegantly simple. First, gather a bottle of food coloring and a large, clear glass container. Chapter 1 plate tectonics power point linkedin slideshare. The following website contains a more detailed and lesson plans on plate tectonics, geodesy, and vlbi.
Which theory explains this and the nearly intersecting fracture zones in the south pacificthe plate tectonic theory or the hydroplate theory. L1 advanced readers plate motions point out that the arrows in figure 20 show the direction of plate motion. Earths lithosphere is broken into separate sections called plates. To help your child visualize the convection process that drives tectonic plate motion, try doing this simple experiment together. Wegeners theory and sea floor maps were used to develop the theory of plate tectonics. The theory of plate tectonics explains how plates and their continents move. Hot mantle from the two adjacent cells rises at the ridge axis, creating new ocean crust. This video briefly discusses the theory of tectonic plates, the different types of plate boundaries and their surface features. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and. 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. The lithosphere is broken up into what are called tectonic plates in the. The top limb of the convection cell moves horizontally away from the ridge crest, as does the new seafloor.
The new model of horizontal movement of the continents was called plate tectonics. Continental drift theory continental drift is the hypothesis that all the continents had once been joined together in a single landmass. Large pieces of the lithosphere that float on the asthenosphere are called. You will recall from a previous chapter that there are three. Plate tectonic theory observing convection currents convection currents are the major driving force behind the movement of tectonic plates. Plate tectonic theory had its beginnings in 1915 when alfred wegener proposed his theory of continental drift.
The theory encompasses the older concepts of continental drift, developed. The plates are mobile, moving in constant, slow motion measured in rates of centimeters per year. The earths crust is divided into plates which are moved in various directions. Plate tectonic theory arose out of the hypothesis of continental drift. 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.
The theory of plate tectonics worksheet teachengineering. The theory of plate tectonics grew out of earlier hypotheses and observations collected during exploration of the rocks of the ocean floor. New crustal plate is formed at the midocean ridges and old crustal plate is destroyed at deep ocean trenches. Plate tectonics the tectonic plates of the world were mapped in the second half of the 20th century. These ridges and fracture zones are in places that are not consistent with the plate tectonic interpretation. Together, these plates constitute the lithosphere, from the greek lithos, meaning rock. Plate tectonics from the late latin tectonicus, from. 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. Dec 17, 2019 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. Choose from 232 different sets of 7th grade science chapter 7 plate tectonics theory flashcards on quizlet. 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 key concepts what is the theory of plate tectonics. Sep 17, 2009 the theory of plate tectonics explains how plates and their continents move. This plate motion causes them to collide, pull apart, or scrape against each other.
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