Fluent Essays

Plate tectonics is a unifying framework for understanding the dynamic geology of the Earth. The theory posits that the outermost layers of the Earth (the crust and uppermost mantle) make up the brittle lithosphere of the Earth. The lithosphere is broken up into a number of thin plates, which move on top of the asthenosphere (middle mantle). The asthenosphere is solid, but flows plastically over geologic time scales. Plate interiors are relatively stable, and most of the tectonic action (earthquakes, volcanism) takes place where plates meet – where they collide at convergent boundaries, move away from one another at divergent boundaries, or slide past one another at transform boundaries. Reconstructions of the Earths tectonic plate locations through time are available, for example, at:http://www.scotese.com/newpage13.htm (Links to an external site.)http://www.ucmp.berkeley.edu/geology/tectonics.html (Links to an external site.)But how do we define plates and plate boundaries? On what are plate reconstructions and animations based? How do we know plates are moving, how can we track their positions in the past, and how can we predict their positions in the future? To answer these questions, this assignment guides you through an examination of patterns on Earth – the topography of the earths surface above sea level, the bathymetry of the ocean floor below sea level, and the distribution of earthquakes and volcanic rock ages. These patterns reveal plate boundaries, just as they did for geologists first developing plate tectonic theory in the 1960s. Youll then use geologic data to determine long-term average plate motions, to predict how our dynamic planet will change in the future.To do this, youll use the program Google Earth, and Google Earth layers compiled from various sources.A. Getting started with Google Earth On your computer, install the latest version of Google Earth Pro from https://www.google.com/earth/versions/ (Links to an external site.) Once installed, open Google Earth, under the Tools/Options/3D View/ menu on a PC, or under the Preferences/3D View menu on a Mac, choose the Decimal Degrees and Meters Kilometers options and makes sure the Use High Quality Terrain box is checked.Open the View menu. Go ahead and experiment with the options, but in general you should just have the Tool Bar, Side Bar and Status Bar checked. Also, on the View menu, hover over Navigation and you will see several options for the compass arrow and slide bars in the upper right corner of the Google Earth screen. Automatically is a good choice as it leaves a ghost of the image visible until you hover over it.Load the DynamicEarth.kmz file from into Google Earth Pro. It is located at https://serc.carleton.edu/sp/library/google_earth/examples/49004.html (Links to an external site.) and is the top file in the Description and Teaching Materials list. You should be able to double-click on the filename and it will open. Or, you can download the file onto your computer first, and then open it in Google Earth Pro by using File/Open and navigating to the file.Once the DynamicEarth.kmz is loaded, click and drag to move it from Temporary Places to My Places. Then save My Places by clicking File/Save/Save My Places. DynamicEarth.kmz will now be available every time you open Google Earth Pro on your computer. When you exit, Google Earth Pro should save My Places for the next time. But you should manually save My Places whenever you make significant changes to it, as Google Earth Pro does not autosave during a session.You now have an interactive view of the Earth! Take some time to explore the Earth with Google Earth and figure out how the navigation works using the keyboard, your touch pad, your mouse. For example:Zoom in and out, move N, S, E, W, grab and spin the globe, etc. The resolution will change as you zoom. Clicking on the N of the navigation compass reorients the view so north is up. At top left, search (and fly to) any place of interest. Zoom in and click on the street view icon (orange stick figure under the compass at top right) to explore an area as if you were on footZoom in to see individual buildings, roads, cars, etc. Go 3D - zoom into a significant topographic feature (e.g. Mount Everest, the Grand Canyon, Niagara Falls). Hold the Shift key down and tilt the terrain using the Up/Down arrows to tilt the terrain, and spin the terrain using the Right/Left buttons. Do the same thing for topographic features on the ocean floor. Note that under Tools/Options/3D View you can increase the vertical exaggeration by up to 3x. This is useful to emphasize subtle features, but is pretty scary when you look at the Grand Canyon that way!On the Google Earth tool bar, click the clock-with-an-arrow icon to explore historical imagery in an area of interest (views through time of your favorite city, for example)By clicking and dragging, you can move things that you have found and want to save, from the Search menu into My Places. You can also re-organize My Places by adding and deleting items, changing the order of things, making subfolders, etc. Explore the built-in items under the Layers menu at bottom left, and Dynamic Earth layers in your Places menu.Expand and contract the folders and subfolders, turn various items on and off, etc. For example, with the Dynamic Earth/Volcanoes of the World layer displayed, right-clicking on a volcano (double-clicking with a Mac) brings up an information box about it. B. Topographic Patterns Uncheck all of the layers and focus on topographic features of the Earth.Topography of the earth ABOVE sea levelAre mountains randomly distributed on the continents, or do they tend to occur in particular patterns (clusters, linear chains, arcs, etc.)?Find Mt. Everest, the highest point on earth. Zoom in enough to see the summit, then pan your cursor around to locate the highest point (elevations shows up in the status bar at the bottom, as long as View/Status Bar is selected). The elevation of Mt. Everest is how many meters?Topography of the earth BELOW sea levelWe are all relatively familiar with the topography of the Earths surface above sea level, but less so with the bathymetry of the Earth below sea level. Before this was known, most people assumed that the seafloor was relatively flat and featureless, and personal experience with lakes and rivers suggested that the deepest part would be in the middle. Actual mapping of the sea floor, however, showed some surprises. Such mapping began in the 1930s but accelerated during World War II with the advent of submarine warfare. Princeton Geosciences Professor Harry Hess played a pivotal role; as captain of the USS Cape Johnson he used the ships echo-sounder to ping the seafloor and measure depth as the ship traversed the Pacific Ocean between battles. After the war, this data led him to propose seafloor spreading, a process crucial to the development of the theory of plate tectonics.Modern methods to measure bathymetry include multi-beam echo sounders that map a wide swath of seafloor, and satellite measurement of variations in sea level due to variations in gravitational pull over bathymetric features – sea level is slightly lower over low spots on the sea floor and slightly higher over high spots.On Google Earth, the bathymetry is shown in shades of blue: the darker the blue, the greater the depth. You can get Google Earth Pro to draw topographic profiles by a) using the Add Path tool to draw a path across a region of interest; b) saving that path to My Places and c) right-clicking on the path in My Places and choosing Show Elevation Profile. In order to see a bathymetric profile of the sea floor, (as opposed to a topographic profile on land), there is one more important step to take. In the information box for the path you create, click on Altitude, and then choose clamped to the sea floor instead of clamped to the ground. Otherwise your profile will simply show you a flat line for the sea surface.Examine the Atlantic Ocean between North/South America and Eurasia/Africa. Note that the deepest part is not the middle; instead, an underwater mountain range runs down the middle of the ocean.Features like this are called mid-ocean ridges or spreading ridges (more on the spreading later in this lab). Zoom in enough to see that although the ridge is a topographic high, it also has a valley (the rift valley) running along the middle of it. In the space below, complete the topographic profile of the Atlantic Ocean floor between South America and Africa. Take a digital photograph of your sketch to including in your lab report.Scan around to see the ocean ridges in the Indian, Pacific and Southern Oceans. If the earths lowest spots arent in the middle of the ocean, where are they? Focus on the west coast of South America, and in the space below complete the topographic profile of the Pacific Ocean floor from South America westward about 600 miles (1000 km). Take a digital photograph of your sketch to including in your lab report.The deep linear features, the lowest points on Earth, are called ocean trenches.Using Google Earth, fly to Challenger Deep, the deepest place on Earth (once Google Earth gets you there, you may have to zoom out to see where you are). Where is it?Challenger Deep reaches 11 km (11,000 meters, equivalent to 36,000 ft) below sea level. Which is greater, the elevation of Mt Everest above sea level (see Question 3), or the depth of Challenger Deep below sea level, and by how much?In the space below, give the locations of three other ocean trenches on Earth.C. Seismic PatternsAn earthquake is a vibration of Earth caused by the sudden release of energy, usually as an abrupt breaking of rock along planar fractures called faults.Earthquakes originate at a point called the focus (or hypocenter) which is not at the surface of the earth, but instead at some depth within the earth. The epicenter of an earthquake is the point directly above the focus on either the land surface or seafloor; the depth of an earthquake has nothing to do with water depth, but instead is the depth in the solid earth from epicenter to focus.Only rocks that are cold and brittle (the earths lithosphere) can be broken in earthquakes. Rocks that are hot and ductile will stretch and deform slowly over time without breaking (the earths asthenosphere) – and thus do not produce earthquakes. So observing where earthquakes occur, both horizontally and with depth, tells us something about where stress is concentrated, and also about the material properties of the earth. (Source: https://www.windows2universe.org/earth/geology/quake_1.html (Links to an external site.))Expand the Lab 1/Earthquakes item and click on the Twenty years of large earthquakes layer to show the epicenters of large earthquakes (those with magnitudes >= 6.0) during a 20-year period.Describe any patterns you see in the distribution of earthquake epicenters over the Earths surface - do they form lines, arcs, circles or clusters? Are patterns connected or disconnected?The different colors refer to the depths of the earthquakes.What color are the shallowest earthquakes?What color are the deepest earthquakes?Look closely at and around the Earths ridges and trenches. The earthquake depth patterns associated with these features are different. Complete the chart below:In the vicinity of ridges.(Scan 1500km or so on either side)In the vicinity of trenches.(Scan ~1500 or so km on either side)Describe the depth or range of depths of earthquakes, and the distribution (symmetric or asymmetric?)Is there any pattern to the depth distribution?Using earthquake depths as evidence, is the Earths lithosphere thicker in the vicinity of ridges or in the vicinity of trenches? Justify your answer.D. Volcano PatternsA volcano is an opening in the Earths surface through which melted rock (magma), volcanic ash and/or gases escape from the interior of the Earth.Leaving the earthquake layer on, click on the Active Volcanoes layer. Describe the relationship between the locations of most active volcanoes and locations of earthquakes:E. Plate BoundariesThe theory of plate tectonics holds that the Earths lithosphere is broken into a finite number of jigsaw puzzle-like pieces, or plates, which more relative to one another over a plastically-deforming (but still solid) asthenosphere. The boundaries between plates are marked by active tectonic features such as earthquakes, volcanoes, and mountain ranges and there is (relatively) little tectonic activity in the middle of plates. Unclick all the layers, and then click on the plate boundary model layer (click the box to show it and then click the + or arrow to expand the legend). This shows plate boundaries and the names of major plates.Find the boundary between the African and South American platesWhere is this plate boundary, relative to the coastlines of Africa and South America?Now click the other layers on and off so that you can see relationships between plate boundaries and these features. If you did not have the plate boundary layer available to you, how could you determine where this plate boundary was? Be sure to consider topography/bathymetry as well as the earthquake and volcano layers. List several ways and be specific.Travel westward across the South American plate to its boundary with the Nazca plateWhere is this plate boundary, relative to South America?If you did not have the plate boundary layer available to you, how could you determine where this plate boundary was? List several ways and be specific.F. Plate motionMotion across the mid-Atlantic ridge: the South American plate vs. the African plateTurn on the Seafloor age and the Plate Boundary Google Earth (GE) layers. The Seafloor age layer shows the ages of volcanic rocks that have erupted and cooled to form the ocean floor. Focus on the Atlantic Ocean. Note that the age bands generally run parallel to the spreading ridges. Seafloor age is a critical piece of evidence for plate tectonics; these are used to reconstruct how ocean basins have developed over time and predict how they may evolve in the future.How many million years (abbreviated Ma) does each colored band represent?On average, continental crust is 2 billion years old; the oldest rocks are 3.8 billion years old, and some of the grains in those rocks are even older. What is the age of the oldest seafloor? _______________________________On average, which is oldest – the continents or the ocean basins? _________________Find the South American plate, the African plate, and the Mid-Atlantic Ridge that marks the boundary between them. What happens to the age of the seafloor as distance increases away from the Mid-Atlantic Ridge?Is crust being created or destroyed at this plate boundary (and other spreading ridges)?Is this plate boundary divergent, convergent, or transform? ________________Focus on the northern Atlantic Ocean, near the east coast of the US and the northwest coast of Africa. How long ago did the northern Atlantic Ocean begin to open up or start spreading? Describe your reasoning.Did the northern Atlantic Ocean basin start to open at the same time as the southern Atlantic Ocean basin? How much older or younger is the northern Atlantic basin than the southern Atlantic basin? Describe your reasoning.G. Putting it all together:Prepare a report documenting this lab activity. Your report should discuss how plate tectonic theory relates to earthquakes, volcanoes, and the bathymetry (sea floor topography) of oceans. Along the way, include answers to all of the questions in this lab. Your paper should be accompanied by the two drawings of your ocean floor profile sketches in questions 3 and 4. Your paper should be well organized and written in flowing paragraph form, instead of just a numbered list of questions and answers. Use APA format, according to the CSU-Global Guide to Writing and APA Requirements (Links to an external site.) including a title page, and citing and referencing any sources that you use to support your work, apart from this lab sheet. RubricGEO101C Mod 1 LabGEO101C Mod 1 LabCriteriaRatingsPtsThis criterion is linked to a Learning OutcomeRequirements10.0 to >8.0 ptsMeets ExpectationIncludes all of the required components, as specified in the assignment.8.0 to >6.0 ptsApproaches ExpectationIncludes most of the required components, as specified in the assignment.6.0 to >4.0 ptsBelow ExpectationIncludes some of the required components, as specified in the assignment.4.0 to >0 ptsLimited EvidenceIncludes few of the required components, as specified in the assignment.10.0 ptsThis criterion is linked to a Learning OutcomeContent10.0 to >8.0 ptsMeets ExpectationDemonstrates strong or adequate knowledge of the materials; correctly represents knowledge from the readings and sources.8.0 to >6.0 ptsApproaches ExpectationSome significant but not major errors or omissions in demonstration of knowledge.6.0 to >4.0 ptsBelow ExpectationMajor errors or omissions in demonstration of knowledge.4.0 to >0 ptsLimited EvidenceFails to demonstrate knowledge of the materials.10.0 ptsThis criterion is linked to a Learning OutcomeCritical Analysis20.0 to >16.0 ptsMeets ExpectationProvides a strong critical analysis and interpretation of the information given.16.0 to >12.0 ptsApproaches ExpectationSome significant but not major errors or omissions in analysis and interpretation.12.0 to >8.0 ptsBelow ExpectationMajor errors or omissions in analysis and interpretation.8.0 to >0 ptsLimited EvidenceFails to provide critical analysis and interpretation of the information given.20.0 ptsTotal Points: 40.0This needs to be in essay format, without any of the questions included and none of the instruction text. Attached is my current paper with all the answers. It just needs to be put into essay format with an intro, references, and conclusion. meyert_geo101c_mod1_intro_to_plate_tectonics_with_google_earth.docx Unformatted Attachment Preview Running head: INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH Introduction to Plate Tectonics with Google Earth Tiffany Meyer GEO101C – Earth Science with Lab Colorado State University – Global Campus Clifford Blizard January 5, 2020 1 INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 2 Introduction to Plate Tectonics with Google Earth The following is a report of plate tectonics using Google Earth of topographic patterns, seismic patterns, volcano patterns, plate boundaries, and plate motion. Topography above sea level Are mountains randomly distributed on the continents, or do they tend to occur in particular patterns (clusters, linear chains, arcs, etc.)? While the mountains occur randomly upon the separate continents, they are distributed in arcs within the continents. This occurs because they follow the subduction zone trench line that produces the mountains. Using Mt. Everest, the highest point on earth. Zoom in enough to see the summit, then pan your cursor around to locate the highest point. The elevation of Mt. Everest is how many meters? The elevation of Mt. Everest is 8,840 meters or 29,002 feet. Topography below sea level Examine the Atlantic Ocean between North/South America and Eurasia/Africa. Note that the deepest part is not the middle; instead, an underwater mountain range runs down the middle of the ocean. Shore of South America leads to the Atlantic Ocean which ends at the shore of Africa. Features like this are called mid-ocean ridges or spreading ridges (more on the spreading later in this lab). Zoom in enough to see that although the ridge is a topographic high, it also has a valley (the rift valley) running along the middle of it. In the space below, complete the topographic profile of the Atlantic Ocean floor between South America and Africa. INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 3 Scan around to see the ocean ridges in the Indian, Pacific and Southern Oceans. Pacific Ocean leads up to the South American shoreline. If the earths lowest spots arent in the middle of the ocean, where are they? The lowest spots occur in ocean trenches. Focusing on the west coast of South America, and in the space below complete the topographic profile of the Pacific Ocean floor from South America westward about 600 miles (1000 km). INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 4 Using Google Earth, fly to Challenger Deep, the deepest place on Earth. Where is it? Challenger Deep is in the Pacific Ocean at the southern end of the Mariana Trench near the Mariana Islands which are near Guam. Challenger Deep reaches 11 km (11,000 meters, equivalent to 36,000 ft) below sea level. Which is greater, the elevation of Mt Everest above sea level, or the depth of Challenger Deep below sea level, and by how much? Challenger Deep is deeper than Mt. Everest is tall by 2,160 meters. Give the locations of three other ocean trenches on Earth: The Kuril Trench is located near Russia in the Pacific Ocean. The New Britain Trench is located in the Pacific Ocean near Guinea. The Bonin Trench is also located in the Pacific Ocean off the coast of Japan. Seismic Patterns Expand the Lab 1/Earthquakes item and click on the Twenty years of large earthquakes layer to show the epicenters of large earthquakes (those with magnitudes >= 6.0) during a 20-year period. Describe any patterns you see in the distribution of earthquake epicenters over the Earths surface - do they form lines, arcs, circles or clusters? Are patterns connected or disconnected? Earthquakes can only occur in rocks where stresses can build up to the point to cause the material to fracture, sending seismic waves through the Earth deeper in the Earth the temperatures are too high, making the rocks to flow, rather than fracture so in real sense we can conclude that the earthquake forms clusters The different colors refer to the depths of the earthquakes. What color are the shallowest earthquakes? What color are the deepest earthquakes? The shallowest earthquakes are blue. The deepest earthquakes are red. INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 5 Look closely at and around the Earths ridges and trenches. The earthquake depth patterns associated with these features are different. Describe the depth or range of depths of earthquakes, and the distribution (symmetric or asymmetric?) Is there any pattern to the depth distribution? In the vicinity of ridges. (Scan 1500km or so on either side) Earthquakes are mostly along the fault lines and usually between 0-33 km in depth. The distribution is mostly symmetric. Most are shallow in depth. In the vicinity of trenches. (Scan ~1500 or so km on either side) Earthquakes range from 0800km but mostly in the 033km range. The distribution is roughly symmetric. Clusters appear along the trenches with most in the shallower depths and fewer as it gets deeper. Using earthquake depths as evidence, is the Earths lithosphere thicker in the vicinity of ridges or in the vicinity of trenches? The Earth’s lithosphere is thicker in the vicinity of the trenches because the crust and older. The build up strain causes more earthquakes. Volcano Patterns A volcano is an opening in the Earths surface through which melted rock (magma), volcanic ash and/or gases escape from the interior of the Earth. Describe the relationship between the locations of most active volcanoes and locations of earthquakes. Most of the active volcanoes are located relatively close the locations of earthquakes. Active volcanoes are overwhelmingly located along fault zones and plate boundaries. Plate Boundaries Using the boundary between the African and South American plates, where is this plate boundary, relative to the coastlines of Africa and South America? The plate boundary relative to the coastlines of Africa and South America is between the two continents. If you did not have the plate boundary layer available to you, how could you determine where this plate boundary was? Without the “plate boundary layer” you could still determine INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 6 where the plate boundary is by analyzing the change in depth where mountains are and volcanic eruptions. Travel westward across the South American plate to its boundary with the Nazca plate. Where is this plate boundary, relative to South America? Relative to South America, the Nazca plate boundary follows the South America coastline. If you did not have the plate boundary layer available to you, how could you determine where this plate boundary was? If the plate boundary layer was unavailable, other methods are available to determine plate boundary. In the instance of the Nazca plate, following the South American coastline provides the plate boundary. Also, tracing the occurrences of volcanoes and earthquakes would provide the plate boundary. Plate Motion Motion across the mid-Atlantic ridge to the South American plate vs. the African plate. Focus on the Atlantic Ocean. Note that the age bands generally run parallel to the spreading ridges. Seafloor age is a critical piece of evidence for plate tectonics; these are used to reconstruct how ocean basins have developed over time and predict how they may evolve in the future. How many million years (abbreviated Ma) does each colored band represent? Each colored band represents 10 million years. On average, continental crust is 2 billion years old; the oldest rocks are 3.8 billion years old, and some of the grains in those rocks are even older. What is the age of the oldest seafloor? On average, which is oldest – the continents or the ocean basins? The oldest seafloor is 10 million years. The continents are older than the ocean basins. INTRODUCTION TO PLATE TECTONICS WITH GOOGLE EARTH 7 Find the South American plate, the African plate, and the Mid-Atlantic Ridge that marks the boundary between them. What happens to the age of the seafloor as distance increases away from the Mid-Atlantic Ridge? The age of the seafloor gets older as the distance increases away from the Mid-Atlantic Ridge. Is crust being created or destroyed at this plate boundary (and other spreading ridges)? The crust is creating new ocean floor as it spreads at this plate boundary. Is this plate boundary divergent, convergent, or transform? The plate boundary is divergent. Focus on the northern Atlantic Ocean, near the east coast of the US and the northwest coast of Africa. How long ago did the northern Atlantic Ocean begin to open up or start spreading? Describe your reasoning. Based on the ages of the oldest rock on the Atlantic Ocean floor, the northern Atlantic Ocean began 160 million years ago. Did the northern Atlantic Ocean basin start to open at the same time as the southern Atlantic Ocean basin? How much older or younger is the northern Atlantic basin than the southern Atlantic basin? The northern Atlantic Ocean basin did not start opening at the same time as the southern Atlantic Ocean basin. The northern Atlantic Ocean basin is approximately 40 million years older as the southern Atlantic Ocean basin is only approximately 120 million years old. Conclusion The above was a report of plate tectonics using Google Earth of topographic patterns, seismic patterns, volcano patterns, plate boundaries, and plate motion. ... Purchase answer to see full attachment