Some life rode on diverging plates, became isolated, and evolved into new species. Jan 28, 2017 theory of plate tectonics was established by alfred wegener. The evidence for plate tectonics is very conclusive. It is a very well supported theory, and while scientific debate continues about small parts or local effects, the overall concept is. Evidence for mantle flowinduced topography includes sedimen tary records. Pdf a mantle convection perspective on global tectonics. That continent eventually separated and drifted apart, forming into the seven. Plate tectonics plate tectonics development of tectonic theory. A middle school lesson on plate tectonics theory for grades 68. In the early 1960s, the emergence of the theoryof plate tectonicsstarted a revolution in the earth sciences. Geologists used a variety of evidence to support their ideas. Evidence from fossils, glaciers, and complementary coastlines helps reveal how plates once fit together.
Since this time, plate tectonics theory has established itself as the fundamental framework to study. Although wegeners continental drift theory was later disproved, it was one of the first times that the idea of crustal movement had been introduced to the scientific community. List and describe the evidence for the plate tectonics theory. Crustal rock age the first piece of evidence is the age of the. 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 theorizes that convection currents in the mantle cause large segments of the earth to move. Today, we have a much broader set of evidence in favor of the hypothesis. Origins of plate tectonic theory earth science visionlearning. In rat and rabbit embryofetal development toxicity studies, no evidence of fetal harm was observed. 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. Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Plate tectonics plate tectonics evidence supporting the hypothesis. When a hypothesis becomes a well tested accepted view it is a theory. Convection currents beneath the plates drive the plates in different directions. 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. Describe the type of plate boundary that forms mountains and islands. In retrospect, this seems to be compelling evidence for continental drift yet it was a subject for. 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. This distribution of fossils led to theories that the southern continents were once joined in a supercontinent called gondwana.
The principal drivers recognized, as of 1 jan 2015, by the geophysics community are components of terrestrial convec. Earths geography has changed through time and continues to change today. Although we cant be sure theories are absolutely correct, they are the accepted explanation for our observations. Powerpoint click to download the ms powerpoint file 146 mbytes pdf click to view or download the presentation in pdf 5 mbytes ht ml cl ick to view the presentation in html format. The theory of plate tectonics links earths internal processes to the distribution of continents and oceans.
The plate tectonics theory suggests that earths crust is broken into many small pieces that move, and that the plate interactions result in earthquakes, mountain ranges, volcanoes and the separation of continents. As it is impossible presently to test the presence of the convection current in the mantle this part of. Evidence was strong that earth s landmasses had moved over time. Timeline of the development of the theory of plate tectonics significant events in the development of the theory of plate tectonics are summarized in the table. Basic concepts, illustrations, examples and new perspectives yaoling niu1,2 with 16 figures abstract.
Similar plant and animal fossils on the shores of distant continents all land on earth fits together like a jigsaw puzzle. The plate tectonics theory tries to explain the movement of the earths lithosphere. He could not provide a satisfactory explanation for the force that pushes or pulls the continents. As they spread apart, magma comes to the surface and becomes new continental crust. It took many years before this theory was accepted as a valid concept. We cannot make a mathematical nor real model of plate tectonics. The plate tectonic theory is the theory of the earths outer shell is divided into several plates that glide over the mantle. Plate tectonics the tectonic plates of the world were mapped in the second half of the 20th century. Over time, the plates move and morph into natural land boundaries.
We now know that, directly or indirectly, plate tectonics influences nearly. Along the way, i disclose details of what real science is all about, details all too often absent in textbooks and classroom discussions. The lithosphere lithosphere is comprised of the upper mantle and the crust, the outer shell of the earth. The theory provides a working model for analyses of phenomena that scientists observe. Plate tectonics is a theory because it provides an explanation of why and how segments of the earth move and cause earthquakes and mountains and volcanos. A theory proposed by alfred wegner that said all continents were once joined 300 million years ago in a single land mass called pangaea. Nplate is not indicated for the treatment of thrombocytopenia due to. The earliest references to this similarity were made in 1596 by flemish cartographer abraham ortelius and later in 1620 by the english philosopher francis bacon, in his. Plate tectonics the theory of plate tectonics this section explains how the lithosphere is broken into separate sections that move. Big ideas our understanding of earth is continuously refined. Theory of plate tectonics was established by alfred wegener. Alfred wegener created the idea of continental drift and wrote the origin of continents and oceans to support his idea. The theory of plate tectonics ppt free download as powerpoint presentation. He suggested that germany could ease its debths after wwi by extracting gold from sea water theoretically up to 56 mg of gold can be extracted from 1 m3 of sea water.
The theory of plate tectonics says the lithosphere is split into different plates that move around on top of the surface of the earth. The earth surface has continuously been changing ever since it was formed, especially regarding the geomorphological and geological phenomena. Crust mantle core crust lithosphere plate movement the crust is broken into plates that move. The theory of plate tectonics explains the formation, movement, and subduction of earths. His ideas have been scientifically proven as time goes on.
The earths crust is divided into six large pieces, and about twenty smaller pieces, by deep fault systems. Since this time, plate tectonic theory has established itself as the fundamental framework to study. Plate tectonics theory, formerly known as the theory of continental drift, is well supported in geology, geography and biology. Others brought forth evidence, but plate tectonics processes and continental drift did not attract wide. Plate tectonics is a good example of how the science community collects evidence and then continuously tests the theory. By definition, the word plate in geologic terms means a large slab of solid rock. Plate tectonics evidence supporting the hypothesis. Plate tectonics describes the distribution and motion of the plates.
The evidence against plate tectonic theory is due to the mechanics of plate movement. This is because convection cell currents have not been proved conclusively to exist due to technological limitations we have never been able to get deep enough into earth to prove the theory. Which is the evidence supporting the theory of plate. 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 pt plate tectonics is the movement of lithospheric plates relative to each other.
Active tectonics along the wadi arabajordan valley transform fault. Article pdf available october 2014 with 7,667 reads. In mice there was evidence of increased postimplantation loss. These smaller, broken plates form a more fluid rock surface in the mantle. Since the development of the theory, geologists have had to reexamine almost every aspect of. Plate tectonics theory is taught in science classrooms around the world, but just 50 years ago it was a hotly contested theory. However, in the 1950s, evidence started to trickle in that made continental drift a more viable idea. Include a few figures that are properly referenced in the text. 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.
Scientists found evidence from molten material, magnetic stripes, and drilling samples to back up wegeners theory. Jul 06, 2018 an internet search of the exact same question will bring up a host of correct answers and links to further reading. The concept of continental drift is more than 175 yr old meyerhoff, 1968. An internet search of the exact same question will bring up a host of correct answers and links to further reading. Plate tectonics is the unifying theory of the earth how did the theory develop. 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. Circularity of the plate tectonics theory is founded on two papers. The beginnings of the theory of plate tectonics date to around 1920, when alfred wegener, the german meteorologist and geophysicist, presented the first detailed accounts of how todays continents were once a large supercontinent that slowly drifted to their present positions. Plate tectonics is the unifying theory of the earth. The significance of polar reversal for the theory of plate tectonics alongside ocean floor spreading provides scientists with almost undisputable empirical evidence that plates are in constant movement and that this movement is created by convection cells that exert huge pressures on the lithosphere and at ocean ridges lay down fresh ocean. Convection current theory cct convection current theory forms the basis of sfst and pt. Mar 20, 2018 the conventional interpretation of the theory of plate tectonics includes an aspect detailing what mechanisms drive plate motions. The strikingly similar paleozoic sedimentary sequences on all southern continents and also in india are an example of evidence that supports continental drift. What are the arguments against the theory of plate tectonics.
They came up with the scientific theory of plate tectonics after considering the pieces of evidence well explore in this lesson. Fossils tell us when and where plants and animals once existed. Evidence of plate tectonics exploring earthquakes it seems javascript is either disabled or not supported by your browser. 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. 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. What is some evidence for the plate tectonics theory. I prepared for todays lesson by projecting and tracing the following document plate tectonics template on a large bulletin board paper. Create a timeline of the events leading to the theory of plate tectonics. Early evidence for plate tectonics magma generation, igneous intrusions, metamorphism, volcanic action, earthquakes, faulting, and folding are usually the result of plate tectonic activity. The earths surface is made up of a series of large plates that can travel up to 2 or 3 cm per year.
Plate tectonics combines these older concepts continental drift by means of seafloor spreading with those of convection or a similar mechanism and polar wandering. The theory of plate tectonics combine which two other theories. As you read each paragraph, take notes about the key ideas in the. The plates are mobile, moving in constant, slow motion measured in rates of centimeters per year.
The theory has caused a revolution in the way we think about the earth. The theory states that the earth is made of several tectonic plates along with several smaller plates. Alfred wegener suggested continental drift theory in the 1920s. It has the power to explain many phenomena, such as volcanoes and earthquakes. It is very well supported theory, and while scientific debate continues about small parts or local effects, the overall concept is accepted as good as fact. Intro to plate tectonic theory plate tectonics is the theory that earths outer layer is made up of plates, which have moved throughout earths history. Wipe the site where nplate is to be injected with an alcohol swab, using a circular motion. Plate tectonics, our major paradigm for how the earth works, was established in the 1960ies following decades of observational research that culminated in key. Explain the process that causes the earths tectonic plates to move. Also known as continental drift, the theory of plate tectonics is the reasoning behind why and how continents are constantly moving.
It supports plate tectonics theory because it shows that the continents are moving in constant relative motion, but doesnt support that the interactions between plates causes volcanic and seismic activity. Each tectonic plate consists of oceanic and continental crust. Continental drift theory alfred wegener, 1922 plate tectonics breakup of pangea. What evidence did scientists find in the himalayas that support the theory of plate tectonics. The theory of continental drift was the first step toward plate tectonic theory, which became the foundation upon which modern geology is built. Since the theory of plate tectonics was first introduced, how far has the tectonic plate were standing on moved. The drawing above is a cross section of the earth showing the components that lie within plate tectonic theory.
Time line of the development of the theory of plate tectonics year event 1596 flemish mapmaker abraham ortelius noted that the coastlines of the continents appear to fit together. Geological evidence for the operation of plate tectonics throughout the. Indications of tectonic activity among the classes of evidence for continental drift and the underlying plate tectonics we may list the shapes of many continents are such that they look like they are separated pieces of a jigsaw puzzle. Lithospheric plates dynamic theory forces which give rise to deformation or change cause of magmatism, metamorphism which affect the earths crust. Over earths vast history, both gradual and catastrophic processes have produced enormous changes. Geophysical evidence for or against the plate tectonics theory compose a two page single spaced essay that provides the geophysical evidence that that supports the plate tectonic theory. Over time the continents moved to their present day locations. Many of the defining features of plate tectonics were explicit or implicit in.
Plate tectonics is the geological theory that states that pieces of earths lithosphere are in constant, slow motion, driven by convection currents in the mantle. As years passed, more and more evidence was uncovered to support the idea that the plates. The theory of plate tectonics grew out of earlier hypotheses and observations collected during exploration of the rocks of the ocean floor. 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 development of tectonic theory britannica.
Plate tectonics, theory dealing with the dynamics of earths outer shell that revolutionized earth sciences by providing a uniform context for. There are three pieces of evidence that help support the theory of plate tectonics, shape of continents, locations of mountains and. Give an example of an island that has been created by a hot spot. Chapter 8 plate tectonics 173 the theory of plate tectonics in the 1950s and 1960s, discoveries about earthquakes, magnetism, and the age of rocks on the ocean floor added support to some, though not all, of wegener s ideas. The outlines of the continents flanking the atlantic ocean are so similar that their correspondence was apparent as soon as accurate maps became available. Scientists have named this the theory of plate tectonics. In 1967, mckenzie and parker suggested the theory of plate tectonics. The theory of plate tectonics ppt plate tectonics mantle. That said, here are some of the namesterms of the key pieces of evidence without great explanation, so people can go and research. Plate tectonics reveals that the lithosphere is divided into eight major pieces plates with several smaller plates fig. It states that earths outer shell is made up of many different plates, all which glide over top the earths mantle. According to the theory of continental drift, the world was made up of a single continent through most of geologic time. Pdf the concept of interplay between mantle convection and tectonics goes back to about a.
The basic theory of plate tectonics is that along seafloor spreading zones, the continents are separating from one another. From wikipedia, the free encyclopedia plate tectonics from greek, tekton builder or mason describes the large. As compelling as this evidence was, wegeners theory was not accepted by the scientific community. Scientists support this theory with evidence from very old plant and animal remains. All this evidence, both from the ocean floor and from the continental margins, made it clear around 1965 that continental drift was feasible and the theory of plate tectonics, which was defined in a series of papers between 1965 and 1967, was born, with all its extraordinary explanatory and predictive power.
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. 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. Though it is just a theory geologic time, ocean trenches, seafloor spreading, mountains, volcanoes, and earthquakes are all examples of evidence that support the theory of plate tectonics. 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. As the crust continues to move, a chain of volcanoes forms evidence of hot spot theory. You will recall from a previous chapter that there are three major layers crust, mantle, core within the earth that are. Plate tectonics plate tectonics is the unifying theory of geology and revolutionized geology cornerstone of earthsystem approach. The story on the discovery of the mid ocean ridges starts with fritz haber, a prominent german chemist nobel prize in chemistry in 1918. This diagnostic sequence consists of glacial deposits called tillites, followed by sandstones and finally coal measures, typical of warm moist. What are four pieces of evidence for continental drift. I also organized a few teacher notes on plate tectonics to help guide class discussions today.
The theory of plate tectonics geology lumen learning. As the tectonic plates move away from spreading zones, they collide with one another. It supports plate tectonics theory because it shows that the continents are moving in constant relative motion, but doesnt support. Describe some of the events and pieces of evidence that led to the theory of plate tectonics. We have a hypothesis of the general mechanics, but there might be pieces of data that do not fit the overall principle. Continental drift, sea floor spreading and plate tectonics.
Glacier deposits mountain ranges from different continents align and are composed of the same materials. This module describes how the work of alfred wegener, harry hess, and others led to our understanding of plate tectonics. All this evidence, including the data collected by alfred wegners for this theory of continental drift, was put together to form the theory of plate tectonics. Since the theory of plate tectonics was first introduced. Jan 23, 2020 plate tectonics is the scientific theory that attempts to explain the movements of the earths lithosphere that have formed the landscape features we see across the globe today. Who proposed the theory and what evidence did he provide to prove his theory. 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. It was from the continental drift theory, convection current theory and the theory of seafloor spreading, the theory of plate tectonics was formulated.
77 880 606 1291 1019 1205 1322 1090 1130 1175 1518 982 1434 315 1052 901 546 844 634 1294 497 352 364 1472 226 383 1001 293 1479 366 777 350 1460 360 464 726 570 942 1009 1275