DOCSLIB.ORG

The Early Stages of Subduction

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Early Stages of Subduction The early stages of subduction Dr Douwe J J van Hinsbergen reflects on his efforts to shed new light on the mechanisms of plate SINK tectonics, attempting to determine the processes that lead to the formation of new subduction zones From what context did your investigation make plate reconstructions of these mountain into Subduction Initiation reconstructed from belts. Normal plate reconstructions assume Neotethyan Kinematics (SINK) emerge? that plates are rigid, they cannot deform and their motion is accommodated along narrow, During my PhD and first two postdoctoral discrete fault zones. Although this approach positions, I studied the formation and evolution is very useful for reconstructing plate motion of mountain belts in the wider Neotethyan on a global scale, it is not directly applicable realm. The Neotethys was a major oceanic to regions where plates converge and where basin system that existed between Gondwana one plate subducts below another – in in the south (a major continental realm that these places, plate boundary zones show contained Africa, Arabia, India and Australia) distributed, spectacular deformation. Using and Laurasia in the north (Eurasia, Greenland structural geological and palaeomagnetic and North America). Its closure eventually data, I have built detailed retro-deformation formed the Alpine-Himalayan mountain belt. models of these mountain belts. From these models, I can derive when and where During my third postdoctoral position at the subduction zones started to form, and along University of Oslo in Norway, I started to what structures. 106 INTERNATIONAL INNOVATION SINK Can you provide an overview of your approach to study the driving forces behind back to the time of their onset, we aim to current project and outline the main aims plate tectonics? define what processes cause the formation of your research? of subduction zones. Is the collision between I have begun to collaborate with geophysicists, two continents sufficient to perturb the SINK mainly focuses on subduction zones that some of whom develop models for the structure forces driving the plate tectonic cycle and existed within the Neotethys Ocean, since of the Earth’s mantle where former surface develop a new subduction zone along a these leave a very distinct rock record known plates can be found that have subducted in the former mid-ocean ridge – or could this only as ‘ophiolites’ – pieces of oceanic crust that geological past; other partners create numerical happen under certain circumstances? Do were thrust over continental margins and models that try to explain elements of plate these apply to the reconstructed history? We which are now exposed on land. motion and subduction based on basic physical will combine the reconstructions with tailor- laws and principles. While geologists can only made numerical models to test whether This particular project aims to create a speculate about the causes and consequences geologists’ speculations are physically breakthrough in our understanding of plate of subduction, geophysicists can show what possible and if the models actually match tectonics by identifying the processes that is theoretically possible. Much of the time, the observations. have led, and may lead, to the formation geophysicists do not know the details of what of new subduction zones. As common as actually happened, so the application of their What are your expectations for the future subduction may be, and as long as we have results alone is not always sufficient. of your research? known of its occurrence, this question has never really been asked and has not been In your research, you reconstruct the By moving beyond studying generic aspects analysed in detail. In more general terms, I geometry and orientation of a subduction of Earth’s behaviour, and isolating what aim to integrate the field of geology (that is, zone at the moment subduction started. exactly happened in terms of the geology and observational analysis of fossils, structures, What questions are you hoping to physics of subduction zone formation in the rocks and minerals) with physics through answer and how do you combine these Neotethys, I hope we can better understand numerical modelling. reconstructions with numerical models? the physics of particular case studies. In the future, I would also like to include the more Could you explain the importance of using Given my interest in subduction zones and detailed geochemistry of mantle-derived an integrated geological and numerical the ability to reconstruct their configuration rocks (volcanoes) in the analysis. Solving the secrets of subduction Using unprecedented multidisciplinary research methods, the SINK project based at Utrecht University is breaking new ground in its studies of the driving forces behind the initiation of subduction zones OF EXISTING GEOLOGICAL theories, plate There is currently no widely accepted entitled Subduction Initiation in Neotethyan tectonics is one of the most revolutionary and physical explanation for what drives plate Kinematics (SINK), van Hinsbergen employs influential. Supported by a weighty and diverse tectonics. While there is broad agreement a highly multidisciplinary approach that is body of evidence, the theory mathematically that the mechanism involves thermal essential to the work’s success. describes the complex evolution of the Earth’s convections in the Earth’s mantle that result lithosphere in terms of constantly shifting in interior cooling, it is only recently that Once stretching between the two plates and their interactions. Understanding technological advances have made it possible supercontinents – Gondwana in the south and plate tectonics is not only important for to reconstruct and explore the dynamic Laurasia in the north – the Neotethys Ocean explaining mountain formation and the history of the mantle itself. on which van Hinsbergen’s study focuses creation of a wide range of georesources, but contains many well-dated and well-exposed it is also vital for predicting natural hazards ophiolites (fragments of oceanic crust) that NEOTETHYAN KINEMATICS such as earthquakes. hold the best-preserved geological record of Dr Douwe J J van Hinsbergen – a structural past subduction initiation events. Subduction of oceanic lithosphere into geologist, palaeomagnetist and field geologist the Earth’s mantle – the process by which – has dedicated his career to the tectonic ‘Kinematics’ refers to the mathematical one tectonic plate is pushed downwards reconstruction of mountain belts. Based at calculation of past movements of the beneath another as the two converge – is a the Department of Earth Sciences at Utrecht Earth’s crust: “We are building a model that key element of plate tectonics. Geophysical University, The Netherlands, he is currently mathematically describes the motions of models demonstrate that forcing is required leading a research project that aims to further all crustal blocks that were involved in the to initiate subduction at weakness zones, understand plate tectonics by identifying the closure of the Neotethys Ocean,” explains van but mechanisms producing this forcing mechanisms that force subduction initiation. Hinsbergen. “The theory of plate tectonics is remain unexplored. A year and a half into the five-year project, kinematic in that it describes the motion of WWW.RESEARCHMEDIA.EU 107 INTELLIGENCE SINK SUBDUCTION INITIATION RECONSTRUCTED FROM NEOTETHYAN KINEMATICS OBJECTIVES • To unravel the processes causing the formation of subduction zones – a key link in the plate tectonic cycle – through geological one plate relative to another. Kinematics is the plate can be offscraped and accreted to the reconstruction and geophysical modelling expression of dynamics, the set of forces that overriding plate. explain why these movements occurred. That is • To develop a predictive model for our ambition: a dynamic explanation.” The researchers led by Van Hinsbergen build exploration of subduction-related models of converging plates using modern- georesource formation day ocean floors: “Our reconstructions A NOVEL APPROACH KEY COLLABORATORS begin in the present day and then recreate Subdivided into several smaller projects, SINK historical Neotethys plate movements step Marco Maffione; Ayten Koç (Postdoctoral is integrating geology and geophysics in a way by step, to the best of our knowledge placing researchers); Derya Gürer; Kalijn Peters; that will help to forge a deeper understanding of all the rocks that are now at the surface back Peter McPhee (PhD students) • Wim subduction initiation: “I have a team of talented into their position when they formed,” he Spakman; Cedric Thieulot; Liviu Matenco; people under my supervision, each with specific explains. Using these reconstructions it is Martyn Drury; Herman van Roermund, aptitudes and skills,” van Hinsbergen enthuses. possible to restore the geological units of a Utrecht University, The Netherlands • Fraukje “Through the combination of our expertise we mountain belt to their configuration before Brouwer, VU University, The Netherlands • hope to gain insights that we wouldn’t be able subduction started to deform them. From Nuretdin Kaymakci, Middle East Technical to develop individually.” this, the researchers can model the geometry University, Turkey • Ercan Aldanmaz, Kocaeli and orientation of a subduction zone at the University, Turkey • Paul Kapp; Peter Lippert, Subduction initiation events, absolute and moment the process began. University of Arizona, USA • Fernando Corfu; relative plate motions,
Load more

Recommended publications
  • Topic B - Geologic Processes on Earth
    Topic B - Geologic Processes on Earth 1 Chapter 6 - ELEMENTS OF GEOLOGY 6-1 The Original Planet Earth Planet Earth formed out of the original gas and dust that prevailed at the origin of the solar system some 4.6 billion years ago. It is the only known habitable planet so far. This is due to the concurrence of special conditions such as its position with respect to the Sun giving it the right temperature range, the preponderance of necessary gases and a shielding atmosphere that protects it from lethal solar radiation. Early Earth has however not always been so welcoming to life. Initially Earth was rich in silicon, iron and magnesium oxide. Heat trapped inside Earth along with radioactive decay which tends to produce more heat helped heavier elements to sink to the depths leaving lighter elements closer to the surface. Within the first 500 million years, an inner core formed of mostly solid iron surrounded by a molten iron outer core. The mantle formed of rocks that can deform. The thin outer crust that sustains life is composed mostly of silicate rocks. The various natural processes inside and on the surface of Earth make it a dynamic system which has evolved into what we know now. These include the oceans and the continents, the volcanoes that form the mountains and erosion that erodes the landscape, earthquakes that shape the topography and the movement of earth’s crust through the plate tectonics process. mantle outer core crust inner core 35 700 2885 5155 6371 Depth in km Figure 6-1: Schematics showing the Earth’s solid inner core, liquid outer core, mantle and curst.
    [Show full text]
  • AGAP Antarctic Research Project Http
    AGAP Antarctic Research Project Image by Zina Deretsky, NSF Image from - http- //news.bbc.co.uk/1/hi/sci/tech/6145642 Build Your Gamburtsev Mountain Formation Mountain Building: Remember mountain ranges can be built in different ways. With the Gamburtsev Mountains there are several possible theories, but with the mountains under ice, there is little data available. Let’s focus on the two main theories, collision and hot spot volcanic activity. Select one theory to support. Your task is to create a model of your mountain building event and explain why you picked it, how your model supports your theory, and what ‘tools of the trade’ from our geophysical tools you could use to test your theory. The Gamburtsevs, the Result of a Collision? Mountain belts are formed along boundaries between the Earth’s crustal (lithospheric) plates. Remember, the Earth’s outside crust is made up of plates (or sections) with pieces that are slowly moving. When the different plates collide they can push or fold the land up forming raised areas, or mountains. The European Alps and the Himalayas formed this way. The sections of Earth’s continental crust are constantly shifting. During the Cambrian Period, a time between ~500 and 250 Ma, the piece of crust that would become Antarctica (we will call this proto-Antarctica) was on the move! Early in the Cambrian it was located close to the equator, a much Proto Antarctica Other Continent milder climate than its current location, but as the Cambrian Period advanced proto-Antarctica moved slowly south. The collision theory suggests that as these pieces of continent moved, like bumper cars they collided with each other.
    [Show full text]
  • Terræ Conceptions of Mountain Formation, Folding, Fault and the Continental Drift in Geography Textbooks Between the Decades Of
    Terræ ARTIGO 10.20396/td.v14i4.8654094 Didatica Conceptions of mountain formation, folding, fault and the continental drift in geography textbooks between the decades of 1930 to 1960 DANILO M. DA COSTA, EDSON R. DE SOUZA INSTITUTE OF GEOSCIENCES, GRADUATE PROGRAM OF TEACHING AND HISTORY OF EARTH SCIENCES. UNIVERSITY OF CAMpiNAS (CAMpiNAS STATE UNIVERSITY), ZEFERINO VAZ UNIVERSITY CAMPUS, RUA CARLOS GOMES, 250, BARÃO GERALDO, 13083-855, CAMpiNAS, SP. E-MAILS: [email protected], [email protected] Abstract: The conceptions about the origins of mountains, faults, folds or relief Manuscript: are very different if we compare didactic books of Geography published before Received: Quadrennial Conference of the International and after the elaboration of Plates Tectonics theory. In this article, it was analyzed Geoscience Education Organization th didactic books from first grade education, which is currently equivalent to the 6 Accepted: 14/01/2018 grade of Elementary School 2, published between 1933 until 1961. Obviously, by that time, Plate tectonics theory had not yet been elaborated. However, Citation: Costa D.M., Souza E.R. 2018. Conceptions of the academic world was already familiar with the Continental Drift theory, an mountain formation, folding, fault and the continental innovative proposal elaborated at the beginning of the 20th century by German drift in geography textbooks between the decades of scientist Alfred Wegener [1880-1930]. According to Wegener, the continents 1930 to 1960. Terræ Didatica, 14(4):349-354. URL: were together millions of years ago, forming a single great mass, called by http://www.ige.unicamp.br/terraedidatica/. him of “Pangea”. Considering that the books analyzed were published between 1933 and 1961, such works could be expected to contemplate and explain the Keywords: Plate Tectonics, continental drift, mountain continental drift theory.
    [Show full text]
  • Lesson 3: Sea Floor to Summit
    Everest Education Expedition Curriculum Lesson 3: Sea Floor To Summit Created by Montana State University Extended University and Montana NSF EPSCoR http://www.montana.edu/everest Lesson Overview: Explore the rocks that lie beneath Mount Everest’s summit. Simulate the formation of the Himalayan Mountains and Mount Everest while uncovering the dynamic processes of plate tectonics. Study the rocky layers that Dr. David Lageson researched on Mount Everest and investigate the geologic layers that sit below each climber’s crampons (ice cleats). Discover how the ancient sea floor now sits on this extreme summit and ponder whether Mount Everest really is the tallest mountain on earth. Objectives: Students will be able to: 1. Explain how the Himalayan Mountains formed. 2. Identify the rock layers of Mount Everest. 3. Explain the different ways each of the world’s four “tallest” mountains are measured. Vocabulary: fault - a crack with offset in the Earth's crust folding - when rocks or rock layers that were once flat are bent or curved gneiss (nice) - a high-grade metamorphic rock formed from preexisting granite or sedimentary rock (high grade metamorphism changes the rock so completely that the source rock often cannot be readily identified) Read more: http://www.answers.com/topic/metamorphism#ixzz1oxKeAZaE granite - an igneous rock that forms from the slow crystallization of silica-rich magma below Earth’s surface limestone - a sedimentary rock composed mostly of calcium carbonate formed in clear, warm, shallow marine waters marble - a metamorphic
    [Show full text]
  • The Geology of the Burke Quadrangle, Vermont
    THE GEOLOGY OF THE BURKE QUADRANGLE, VERMONT By BERTRAM G. WOODLAND off tC 200 STE STREET VERMONT GEOLOGICAL SURVEY CHARLES G. DOLL, State Geologist Published by VERMONT DEVELOPMENT DEIARTMENT MONTPELIER, VERMONT BULLETIN No. 28 1965 - Fiure 1. Fiontispie c Burke Mountain, Umpire \Iountain (left), and the northern spur of Kirby Mountain right) are resistant e-'se' of homteled Gilc \lount'&in fonuttion jj nuuite. View southeist\vards from near Marshall Swhool. TABLE OF CONTENTS PAGE ABSTRACT 9 INTRODUCTION ...................... 10 Location ........................ 10 Methods of study .................... 10 Acknowledgments .................... 12 Physiography ...................... 14 Settlement ....................... 17 Previous work ..................... 18 STRATIGRAPHY ...................... 19 General statement .................... 19 Thicknesses ..................... 19 Age of formations ................... 20 Sequence ....................... 20 Albee Formation ..................... 21 Amphibolite ...................... 22 Waits River Formation ................. 23 Impure limestone ................... 23 Pelitic rocks . . . . . . . . . . . . . . . . . . . . 24 Psammitic beds .................... 25 Amphibolite ...................... 27 Light-colored hornblende quartzose bands . . . . . . . 31 Meta-acid igneous rocks ................ 31 Gile Mountain Formation ................. 34 Quartzose phvllite ....................35 Pelitic rocks ...................... 39 Amphibolite . . . . . . . . . .
    [Show full text]
  • Redalyc.Timing and Implications of Late Cretaceous Tectonic And
    Geologica Acta: an international earth science journal ISSN: 1695-6133 [email protected] Universitat de Barcelona España Mitchell, S.F. Timing and implications of Late Cretaceous tectonic and sedimentary events in Jamaica Geologica Acta: an international earth science journal, vol. 4, núm. 1-2, 2006, pp. 171-178 Universitat de Barcelona Barcelona, España Available in: http://www.redalyc.org/articulo.oa?id=50540209 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Geologica Acta, Vol.4, Nº1-2, 2006, 171-178 Available online at www.geologica-acta.com Timing and implications of Late Cretaceous tectonic and sedimentary events in Jamaica S.F. MITCHELL Department of Geography and Geology, University of the West Indies Mona, Kingston 7, Jamaica. Email: [email protected] ABSTRACT The Cretaceous succession in Jamaica can be divided into sedimentary packages bounded by major unconfor- mities (synthems). On the base of biostratigraphy and ages derived from strontium isotope ratios, these uncon- formities have been dated as Early Santonian, Late Campanian-Early Maastrichtian and Early Eocene. Each unconformity is also characterised by the widespread deposition of shallow water limestones, and a further shal- low limestone depositional event occurred in the late Middle Campanian. Some unconformities can be related to known tectonic events (based on either Burke-type or Pindell-type models) that affected the Caribbean region. The Early Santonian event is widespread and occurred shortly after the creation of the Caribbean Large Igneous Province.
    [Show full text]
  • Mountain Formation
    Mountain formation 2 Listen and read the text about mountains. Which type of mountains are formed when: a magma erupts from under the Earth? b magma pushes up under the Earth, but doesn’t erupt? c two tectonic plates push together? d water or wind cut away the land? e rock is pushed up through a crack in the Earth? The top layer of the Earth (the crust) is divided into seven large, independent sections, called tectonic plates. Below the Earth’s crust is the mantle – a layer of very hot, solid rock with some semi-molten rock called magma. Most mountains are formed by the movement of tectonic plates and rising magma. 1 Fold mountains are created when two tectonic plates collide. Their edges push together and up, causing mountains to be formed where they meet. Example: the Himalayas in Asia, the Alps in Europe Venture Level 2 . Mountain formation, p.255 © Oxford University Press PHOTOCOPIABLE 2 Fault-block mountains are formed when rock is forced up a crack in the Earth’s crust. They usually have a steep front and a sloping back. Example: the Sierra Nevada Mountains in North America 3 Volcanic mountains are created when magma pushes through the Earth’s crust and erupts. The material that erupts falls on the ground and becomes solid. With each future eruption, this material gradually builds into a mountain. Example: Mount Fuji in Japan 4 Dome mountains occur when magma pushes up under the Earth’s crust without erupting. The magma then cools and hardens, leaving a dome-shaped mountain.
    [Show full text]
  • A Stratigraphic and Geochronologic Analysis of the Morrison Formation/Cedar Mountain Formation Boundary, Utah
    Brigham Young University BYU ScholarsArchive Theses and Dissertations 2006-07-08 A Stratigraphic and Geochronologic Analysis of the Morrison Formation/Cedar Mountain Formation Boundary, Utah Brent W. Greenhalgh Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Geology Commons BYU ScholarsArchive Citation Greenhalgh, Brent W., "A Stratigraphic and Geochronologic Analysis of the Morrison Formation/Cedar Mountain Formation Boundary, Utah" (2006). Theses and Dissertations. 916. https://scholarsarchive.byu.edu/etd/916 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. A STRATIGRAPHIC AND GEOCHRONOLOGIC ANALYSIS OF THE MORRISON FORMATION/CEDAR MOUNTAIN FORMATION BOUNDARY, UTAH by Brent W. Greenhalgh A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Copyright © 2006 Brent W. Greenhalgh All Rights Reserved BRIGHAM YOUNG UNIVERSITY GRADUATE COMMITTEE APPROVAL of a thesis submitted by Brent W. Greenhalgh This thesis has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory. ________________________ ______________________________________ Date Brooks B. Britt, Chair ________________________ ______________________________________
    [Show full text]
  • Convergent Plate Margin Dynamics: New Perspectives from Structural Geology, Geophysics and Geodynamic Modelling
    Tectonophysics 483 (2010) 4–19 Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto Convergent plate margin dynamics: New perspectives from structural geology, geophysics and geodynamic modelling W.P. Schellart a,⁎, N. Rawlinson b a School of Geosciences, Monash University, Melbourne, VIC 3800, Australia b Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia article info abstract Article history: Convergent plate margins occur when two adjoining tectonic plates come together to form either a Received 26 May 2009 subduction zone, where at least one of the converging plates is oceanic and plunges beneath the other into Received in revised form 28 August 2009 the mantle, or a collision zone, where two continents or a continent and a magmatic arc collide. Convergent Accepted 31 August 2009 plate margins are arguably the most complicated and dynamic plate boundaries on Earth and have been the Available online 10 September 2009 subject of many investigations and discussions since the advent of plate tectonic theory. This paper provides a historical background and a review of the development of geological and geodynamic theories on Keywords: convergent plate margins. Furthermore, it discusses some of the recent advances that have been made in the Convergent plate margin fi Subduction elds of structural geology, geophysics and geodynamics, which are fundamental to our understanding of Collision this phenomenon. These include: (1) the finding that plates and plate boundaries move at comparable Orogenesis velocities across the globe; (2) the emerging consensus that subducted slabs are between two to three orders Slab of magnitude stronger than the ambient upper mantle; (3) the importance of lateral slab edges, slab tearing Plate tectonics and toroidal mantle flow patterns for the evolution of subduction zones; and (4) clear evidence from mantle tomography that slabs can penetrate into the lower mantle.
    [Show full text]
  • Chapter 10 Plate Tectonics
    Chapter 10 Plate Tectonics Learning Objectives After carefully reading this chapter, completing the exercises within it, and answering the questions at the end, you should be able to: • Discuss some of the early evidence for continental drift and Alfred Wegener’s role in promoting this theory. • Explain some of the other models that were used early in the 20th century to understand global geological features. • Describe the numerous geological advances made in the middle part of the 20th century that provided the basis for understanding the mechanisms of plate tectonics and the evidence that plates have moved and lithosphere is created and destroyed. • List the seven major plates, their extents, and their general directions of motion, and identify the types of boundaries between them. • Describe the geological processes that take place at divergent and convergent plate boundaries, and explain the existence of transform faults. • Explain how super-continents form and how they break apart. • Describe the mechanisms for plate movement. As we discovered in Chapter 1, plate tectonics is the model or theory that we use to understand how our planet works. More specifically it is a model that explains the origins of continents and oceans, folded rocks and mountain ranges, igneous and metamorphic rocks, earthquakes (Figure 10.0.1) and volcanoes, and continental drift. Plate tectonics was first proposed just over 100 years ago, but did not become an accepted part of geology until about 50 years ago. It took 50 years for this theory to be accepted for a few reasons. First, it was a true revolution in thinking about Earth, and that was difficult for many established geologists to accept.
    [Show full text]
  • Subduction Zone Backarcs, Mobile Belts, and Orogenic Heat
    VVOL.OL. 115,5, NNO.O. 2 A PPUBLICATIONUBLICATION OFOF TTHEHE GGEOLOGICALEOLOGICAL SSOCIETYOCIETY OOFF AAMERICAMERICA FFEBRUARYEBRUARY 22005005 Subduction zone backarcs, mobile belts, and orogenic heat Inside: Subduction zone backarcs, mobile belts, and orogenic heat, ROY D. HYNDMAN, CLAIRE A. CURRIE, AND STEPHANE P. M AZZOTTI, p. 4 2004–2005 Division Officers and Past Chairs, p. 11 GeoVentures™ 2005, p. 29 An Earth Scientist’s Periodic Table of the Elements and Their Ions by L. Bruce Railsback An Earth Scientist’s Periodic Table of the Elements and form as ions rather than in elemental form. The immediate Their Ions is a new periodic table designed to contextualize result is a completely rearranged table in which many trends in geochemistry, mineralogy, aqueous chemistry, elements appear multiple times, because many elements and other natural sciences. First published as an insert assume different charge under different natural conditions. in the September 2003 issue of Geology, this version is The practical result is that many trends in mineralogy, updated and supersized—36" by 76"! seawater chemistry, soil chemistry, the chemistry of This new periodic table of the elements is more useful Earth’s crust and mantle, the chemistry of sediments, and to earth scientists than the conventional periodic table nutrient chemistry become apparent in ways that are not used by chemists. The periodic table presented here recognizable on conventional, elementally constructed, acknowledges that most natural matter occurs in charged periodic tables. MCH092F, 1 folded sheet (36" × 76"), 7 p. text $25.00, member price $20.00—folded MCH092R, 1 rolled sheet (36" × 76"), 7 p.
    [Show full text]
  • Tectonics, Earthquakes, & Volcanism
    The Geosphere: Earth’s Interior & Surface During the twentieth century, new research revolutionized our understanding of Earth sci- ence. These discoveries explained how volcanoes such as Ecuador’s Tungurahua were formed and how the continents and oceans came Tectonics, to their present arrangement. The theory of plate tectonics—the main subject of this chapter—provides a Earthquakes, unified explanation for the pat- terns of earthquakes, volcanoes, and mountain building that domi- & Volcanism nate our planet. Events such as the March 2011 earthquake and tsunami that devastated Japan turn world attention to the Earth sciences, including physical geogra- 8 phy, for explanations. SAMPLE CHAPTER M08_CHRI4744_01_SE_C08.indd 2 30/09/15 1:00 AM What Are Earth’s History, Interior Structure, How Does Plate Tectonics Explain Changes 1 & Materials? 2 in Earth’s Surface? 8.1 The Vast Span of Geologic Time 8.4 Plate Tectonics 8.2 Earth’s History & Interior 8.5 Seafloor Spreading & Subduction Zones 8.3 The Rock Cycle 8.6 Plate Boundaries How Do Plate Motions Affect 3 Earth’s Crust? 8.7 Deformation, Folding, & Faulting 8.8 Earthquakes 8.9 Volcanoes 8.10 Mountain Building Mount Tungurahua in Ecuador is one of many active volcanoes in the Andes mountain chain that extends along the western coast of South America. SAMPLE CHAPTER M08_CHRI4744_01_SE_C08.indd 3 30/09/15 1:00 AM 4 What Are Earth’s History, Interior Structure, & Materials? 8.1 The Vast Span of Geologic Time Key Learning Concepts ago” shown on the time scale. In contrast, relative time is ▶ Describe the geologic time scale.
    [Show full text]