The earth is the only planet known to currently have plate tectonics. The theory of plate tectonics, like every scientific theory, resulted from centuries of observations and compilation of many scientists works. 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 surface of the earth is divided into a number of rigid plates that extend from the surface to the base of the lithosphere. Central to the theory of plate tectonics is the concept of. In essence, platetectonic theory is elegantly simple. The earth surface has continuously been changing ever since it was formed, especially regarding the geomorphological and geological phenomena. Each type of interaction causes a characteristic set of earth structures or tectonic features.
The theory of plate tectonics explains how plates and their continents 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. Plate tectonic theory arose out of the hypothesis of continental drift. Demonstrating the movement of the earths crust and how tectonic plates interact at plate boundaries the theory of plate tectonics. When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around earths surface.
Plate tectonics the tectonic plates of the world were mapped in the second half of the 20th century. 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. Revival of the continental drift theory wegeners theory just would not go away, despite. Rigid plates can bend when subject to a load such as volcanism or seamounts e. According to the theory of plate tectonics, the earths lithosphere is broken into distinct. The concept of plate tectonics was formulated in the 1960s. Instead of plowing directly over mantle, the continents are passengers on the tops of much thicker plates. Chapter 1 plate tectonics power point linkedin slideshare. Because of the strength and rigidity of oceanic plates, deformation is focused into narrow linear zones along plate margins.
Plate tectonics is the theory that explains the global distribution of geological phenomena. Principally it refers to the movement and interaction of the earths lithosphere. Many scientists consider the widespread acceptance of the plate tectonic model as a revolution in the earth sciences. The theory of plate tectonics links earths internal processes to the distribution of continents and oceans. In 1967, mckenzie and parker suggested the theory of plate tectonics. The theory of plate tectonics key concepts what is the theory of plate tectonics.
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 your answers to the questions and click next to see the next set of questions. Name the missing tectonic plates in the blanks on the image below. Scientists do not know for sure what causes tectonic plates to move.
Plate tectonics and crustal evolution sciencedirect. According to the theory of plate tectonics, the earths lithosphere is broken into distinct plates which are. A plate can comprise both oceanic and continental lithosphere. Plate tectonics describes the distribution and motion of the plates. The major mountainbuilding idea that was supported from the 19 th century and into the 20 th is the geosynclinal theory. These fragmented plates ride next to each other on top of the earths more fluid lower mantle to create different types of plate boundaries that have shaped the earths. Fossils tell us when and where plants and animals once existed. Closely spaced earthquakes with a range of depths that deepen i. Plate tectonics theory is taught in science classrooms around the world, but just 50 years ago it was a hotly contested theory.
You will recall from a previous chapter that there are three. The theory has caused a revolution in the way we think about the earth. Two plates move slide laterally past each other, and no oceanic crust is created or destroyed. Tectonic plates are able to move because the earths. 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. 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.
Mar 01, 2016 this video briefly discusses the theory of tectonic plates, the different types of plate boundaries and their surface features. The continents are carried on some of these plates. 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. Boundaries have different names depending on how the two plates are moving in relationship to each other. The theory of plate tectonics grew out of earlier hypotheses and observations collected during exploration of the rocks of the ocean floor.
This movement results in earthquakes in the short term, and the movement of continents over hundreds of millions of years. The theory of plate tectonics continued why do tectonic plates move. Plate tectonicsthe unifying theory of geology geology u. List and describe the evidence for the plate tectonics theory. Generally, the depth of an earthquake is related to the type of tectonic boundary in which it occurs. Continental drift theory, its development and supporting evidence. Plate tectonics the earths crust is divided into plates which are moved in various directions. The earths crust is divided into plates which are moved in various directions. Ocean basinsoceanic crust are continually being created and destroyed through tectonic processes. 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. Along spreading centers in the sea floor, melted rock rises through cracks, cools, and forms new crust that builds up midocean ridges. Plate tectonics plate tectonics is a theory which states that planet earths lithosphere the crust and the upper mantle is made up of solid plates which float on an underground ocean of magma. Tectonic plates theory, major plates, different types of tectonic plates.
To help your child visualize the convection process that drives tectonic plate motion, try doing this simple experiment together. As two adjacent plates move across the asthenosphere, they either collide, slide past another, or separate. Wegeners theory and sea floor maps were used to develop the theory of plate tectonics. First, gather a bottle of food coloring and a large, clear glass container.
Ending with show what you know quiz and extension ac. The theory encompasses the older concepts of continental drift, developed during the. Several maps are provided in the chapter to identify various locations of the world that consist of the major lithospheric plates, plate boundaries, and hotspots. 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. The structure of the earth, plate tectonics and landforms. As ideas concerning plate tectonics have evolved since the 1970s, it has become apparent that while the theory can be applied rigorously to the oceans, the same cannot be said of the continents. It started as a hypothesis and had to be proven with hard evidence before being completely accepted by the scientific community. 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. 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. Plate tectonicsthe unifying theory of geology geology. From wikipedia, the free encyclopedia plate tectonics from greek, tekton builder or mason describes the large scale motions of earths lithosphere. 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. The motion of lithospheric plates is a considerable consequence of thermally driven mass movements on the earth. Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together.
The new model of horizontal movement of the continents was called plate tectonics. The fundamental concepts for geosynclinal theory were introduced in james halls presidential address for the geological society of america at the meeting of the american association for the advancement of science at montreal in 1857 knopf, 649. Plate tectonic theory recognizes that the lithosphere is broken into plates, jigsaw like pieces of various sizes. The plates of crust and stiff mantle lithosphere move on the softer mantle layer beneath. 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 is the theory that earths outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The theory encompasses the older concepts of continental drift, developed. The lithosphere is broken up into seven very large continental and oceansized plates, six or seven mediumsized regional. Plates are composed of lithosphere, about 100 km thick, that float on the ductile asthenosphere. Continental drift, sea floor spreading and plate tectonics. This plate motion causes them to collide, pull apart, or scrape against each other.
The crust is made up of six major plates and a number of minor ones. Together, these plates constitute the lithosphere, from the greek lithos, meaning rock. It provides a means by which continents can drift apart. Earths lithosphere is broken into separate sections called plates. They have three main hypotheses to explain plate movements. Geosynclinal theory the emergence and evolution of plate. This includes the formation, movement, collision and destruction of plates and the resulting geological events such as seismicity, volcanism, continental drift, and. Plate tectonics information and facts national geographic. Plate tectonic theory observing convection currents convection currents are the major driving force behind the movement of tectonic plates. Some life rode on diverging plates, became isolated, and evolved into new species. Since the development of the theory, geologists have had to reexamine almost every aspect of.
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. Theory of continental drift proposed by alfred wegener in 1912, but not widely accepted until seafloor spreading was discovered in 1960. Modern continents hold clues to their distant past. Introduction to plate tectonic theory, geodesy, and vlbi. Lithospheric plates lithospheric plates are rigid and behave elastically. The theory of plate tectonics geology lumen learning.
The theory of plate tectonics understanding main ideas label each. It was shown that the rocks were youngest at the mid ocean ridges and increased with age, in both directions as the ridge was left behind. Plate transmit stress over long distances providing important implications for plate driving mechanisms. The earths lithosphere is composed of seven or eight major plates. Like the scientists before us, we will now merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics. Sep 17, 2009 the theory of plate tectonics explains how plates and their continents move. Plate tectonics is a theory developed in the late 1960s, to explain how. Scientists used to think that convection in the mantle was the main force that caused plate motions. 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.
This plate motion causes them to collide, pull apart, or scrape. Tectonic theories attempt to explain why mountains, earthquakes, and. The tectonic plates of the world were mapped in the second half of the 20th century. The movement of the plates creates three types of tectonic boundaries. Midocean ridges are essentially submerged mountain chains that are characterised by a deep central rift valley. Tectonic plates huge pieces of lithosphere that slowly move on the asthenosphere and consist of the crust. Tectonic plates are composed of oceanic lithosphere and. The study of how these plates move and interact and the consequences thereof is called plate tectonics from the greek word, tekton, which means. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory. Plate tectonics grew out of a theory that was first developed in the early 20th century by the meteorologist alfred wegener. The cross section should really be curved to correspond. Plate tectonics tectonics plate movements plate tectonic.
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. North american plate a tectonic plate division of the lithosphere that includes. 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. 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. The lithosphere is broken up into what are called tectonic plates in the. Introduction and tectonic plates outline today plate tectonics introduction heat energy in the earth heat conduction lithospheric plates dynamic theory forces which give rise to deformation or change cause of magmatism, metamorphism which affect the earths crust. Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig. This video briefly discusses the theory of tectonic plates, the different types of plate boundaries and their surface features.
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