Laboratory 2 _ Plate Tectonics and the Rock Cycle_ ESS 101 B Wi 24_ Introduction To Geology And Soci

.pdf

School

University of Washington *

*We aren’t endorsed by this school

Course

101A

Subject

Geology

Date

Apr 3, 2024

Type

pdf

Pages

32

Uploaded by BrigadierDog3907

2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 1/32 Laboratory 2 : Plate Tectonics and the Rock Cycle Due Jan 21 at 11:59pm Points 15 Questions 40 Available Jan 12 at 9am - Jan 21 at 11:59pm Time Limit None Allowed Attempts 3 Instructions Use the quiz questions below to complete the answer sheet for the Laboratory 2 (Plate Tectonics and the Rock Cycle) exercise. The Pre-lab Video serves as an introduction to the topics covered in this lab. Find the Pre-lab Video here (https://www.youtube.com/watch?v=b5P_OQ_5gyg&feature=youtu.be) . NOTE ABOUT IMAGES : You can find all of the figures embedded in this quiz in Files --> Lab Instructions --> Lab 2: Plate Tectonics & the Rock Cycle . Figures in the Questions are in that folder and are labeled with the relevant question number. Figures in the Introduction are within the folder Figures in Introduction . You have two attempts for this quiz. Some thought-provoking questions and discussion ideas to think about. Before you make your first attempt on Lab 2 this week watch the video (link embedded below) showing the tectonic plate and paleogeographic evolution of Earth over the past 540 million years. Pay attention to where the continents (or segments of continents) are located over geologic time and the tectonic boundaries (divergent, convergent and transform) and motion that cause the change. Pay attention paleo-sea level and mountain building events that occur over time. Think about how the paleogeographic changes (i.e., latitude location, altitude, continentality) will affect the climate (modern climate zone map shown below the Plate Tectonic video) and paleoenvironment of a given location. For example 320 million years ago the continental landmasses presently comprising India, southern South America, southern Africa, Australia, and Antarctica were situated over the south pole. Think about polar latitudes and climates today? At this time period (320 million years ago) North America and western Europe were located near the equator. Think about equatorial latitudes and climate today. Of course, life forms were very different way back in time, but the paleoclimate zones would be strongly controlled by tectonic plate configurations. Some questions to think about: 1. Why does Australia have such unique faunal (animals) assemblages that have evolved over the past 150 million years. 2. Why do you think North America and Eurasia have similar grazing animals (deer family, ungulates) that have evolved over the past 60 million years.
2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 2/32 This quiz was locked Jan 21 at 11:59pm. Attempt History Attempt Time Score LATEST Attempt 1 155 minutes 13 out of 15 Answers will be shown after your last attempt Score for this attempt: 13 out of 15 Submitted Jan 21 at 6:05pm This attempt took 155 minutes. Question 1 0.2 / 0.2 pts 3. Africa and South America have primates present on both continents. What does this tell you about the timing of when a common primate ancestor lived on earth. Human evolved from the African primate group at a later time. Plate Tectonics, 540Ma - Modern World - Scotese Animatio Plate Tectonics, 540Ma - Modern World - Scotese Animatio … climate-zones2.jpg 5 major climate zones of the world. Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying answers from a friend or classmate, copying answers verbatim found on the internet or other literary sources, or copying any work that may answer the question being asked. Make sure you always use your own words when answering the questions in the homework and cite appropriate references if you use them to help you answer the
2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 3/32 True False question. Violations the academic code of conduct (https://www.washington.edu/cssc/for-students/academic- misconduct/) will will be reported to the UW Academic Misconduct representative for investigative review. I acknowledge that I have carefully read and understand the above statement regarding the consequences of cheating and plagiarism, and promise to complete my work in this class with honesty and integrity. Answer "True" below supporting your acknowledgement. Learning Goals: By completing this lab, students will become more familiar with: The three types of plate boundaries: convergent, divergent, and transform The different types of magma associated with each type of plate boundary The plate tectonic map of the Circum-Pacific Basin The relationship between plate tectonics, volcanoes, and earthquakes The Hawaii-Emperor Seamount chain and using distance-time relationships of the volcanic islands to describe historical tectonic movement Plate Tectonics Overview Plate tectonics links together many aspects of geology. Plate tectonics describes how the earth’s thin, outer lithosphere is broken into plates that slowly move over the asthenosphere (Figure 2-1). These brittle rock plates have thicknesses of 10 to 100 km and move over the ductile rock of the asthenosphere at rates of 1 to 10 cm/year. This is about the same rate at which your fingernails grow! The forces that drive plate motion are primarily ridge-push and slab-pull gravity forces. See Incorporated Research Institutions for Seismology video on the forces that drive plate tectonics (select animation tab). (https://www.iris.edu/hq/inclass/animation/what_are_the_forces_that_drive_plate_tectonics)
2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 4/32 Figure 2-1: Earth’s tectonic plates. The black lines indicate the boundaries between plates, and the red arrows indicate the relative motions at plate boundaries . Chemical and physical layers of the earth Earth’s structure can be classified by chemical composition or by physical properties. The chemical layers of the Earth are the crust, mantle, and core. The crust is mainly composed of igneous rocks (that is, rocks that formed when hot magma cooled at earth’s surface). Continental crust is made of felsic (silica-rich) rocks like granite, and oceanic crust is made of mafic (silica-poor) rocks such as basalt. Below the crust is the mantle , which is made of silicate minerals that are rich in iron and magnesium. Generally, rocks that are silica-rich tend to have relatively lower iron-magnesium (Fe-Mg) content. The physical layers of the outer earth are the lithosphere and the asthenosphere (Figure 2-2). Tectonic plates are pieces of the lithosphere , a layer of brittle rock. The plates slide over the asthenosphere, a layer of ductile, mantle rock. 1
2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 5/32 Figure 2-2: Cross-section of the outer solid Earth . The lithospheric plates slide over the asthenosphere . Oceanic lithosphere forms at mid-ocean ridges (divergent margins) and descends back into the asthenosphere in subduction zones (convergent margins). 2 Plate Boundaries Volcanoes and mountains form at plate boundaries, and plate boundaries produce strong earthquakes. There are three types of plate boundary: 1. Divergent , where two plates are moving apart. 2. Convergent , where two plates are moving together. There are three different types of convergent margins: Ocean-ocean , where oceanic crust converges with oceanic crust. At this type of margin, the denser of the two plates will dive beneath the other, and create a subduction zone (e.g. the Marianas Trench). Ocean-continent , where oceanic crust converges with continental crust. At this type of margin, the denser oceanic crust will dive beneath the less dense continental crust and create a subduction zone (e.g. the Cascadia subduction zone). Continent-continent , where continental crust converges with continental crust. At this type of margin, both plates are relatively buoyant and do not want to sink down. Therefore, subduction does not occur and the two plates collide together to form mountain ranges such as the Himalaya Mountains (formed by the collision of the Indian and Eurasian plates). 3. Transform , where two plates with ocean and/or continental crust are sliding past each other. Volcanoes Volcanoes are places where liquid rock erupts onto the surface of the earth. Volcanoes often form at divergent and convergent boundaries, but they can also form in the middle of plates due to mantle hot spots or rifting. Some important concepts and distinctions for volcanic systems include:
2/25/24, 6:21 PM Laboratory 2 : Plate Tectonics and the Rock Cycle: ESS 101 B Wi 24: Introduction To Geology And Societal Impacts https://canvas.uw.edu/courses/1699809/quizzes/1953691 6/32 Magma is liquid rock found beneath the surface of the Earth. Lava is liquid rock found on the surface of the Earth. Igneous rocks form when magma or lava cools into a solid. Volcanic rocks are igneous rocks that form on the surface (where cooling of lava is rapid), and plutonic rocks are igneous rocks that form underground (where cooling of magma is slow). Plate Boundary Volcanoes: (1) Divergent Margins As two plates move apart, the space that was once occupied by the plates is replaced by upwelling mantle asthenosphere. As this mantle material ascends, it experiences decreasing pressures, which causes it to melt. This process is known as decompression melting. Eventually, this melt either reaches the surface as basaltic lava and cools to create a new crust, or it cools as basaltic magma beneath the surface to create new mantle lithosphere. All oceanic lithosphere is created in this way at mid-ocean ridges (Figure 2-3). Figure 2-3: Divergent plate margin and zone of upwelling of magma. Oceanic lithosphere is generated at the ridge axis, cooling and increasing in thickness as it moves away from the plate margin. [From Igneous Petrogenesis by M. Wilson.] (2) Convergent Margins At convergent margins, if one plate is denser than the other it will subduct beneath the less dense plate, forming a subduction zone. Subduction zone magmas form when the downgoing plate is heated and thus dehydrated. The water squeezed out of the subducting plate lowers the melting point of the rocks in the overlying mantle and initiates melting. This is like how adding salt to ice lowers the melting point of the ice, allowing the ice to melt at a colder temperature. This magma rises and erupts on the surface of the Earth, resulting in volcanic activity. At ocean-ocean subduction zones, this volcanic activity creates an arcuate chain of volcanoes on the overlying plate known as an island arc (e.g. the Philipine and Aluetian islands, Figure 2- 4A). At ocean-continent subduction zones, this same feature is called a continental arc (e.g. the Cascades and Andes volcanoes, Figure 2-4B). Island arc magmas only pass through oceanic lithosphere (which is predominantly basaltic) on their way to the surface, so their composition tends to be more mafic, ranging
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help