Shake and Bake on a Restless Earth: Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Richard W. Wiener
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OBJECTIVES
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Shake and Bake on a Restless Earth: Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Richard W. Wiener
Course Objectives • Appreciate and understand our Earth is dynamic, not static The Rock Cycle: Ever-Changing Earth
Plate Tectonics 250 Ma- today
Continents move, oceans grow and shrink
Mountains erode Rivers shift, deposit sed, erode Shorelines migrate out, in, lateral Sediments deposit / accumulate Sediments buried turn into rocks Rocks metamorphose and melt Magma crystallizes or explodes
Shake and Bake on a Restless Earth: Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Richard W. Wiener
Course Objectives (cont.) • Understand theory of plate tectonics and continental drift and tectonic control on distribution and types of earthquakes, volcanoes, and tsunami.
Shake and Bake on a Restless Earth: Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Richard W. Wiener
• Gain basic understanding of the origin and hazards associated with earthquakes, volcanoes and tsunami.
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics COURSE OUTLINE • • •
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Introduction: Course Objectives, Outline, Basics of Plate Tectonics and Geology Earth’s Interior: Structure, Composition, and Temperature Plate Tectonics and Continental Drift: Theory, Data, Mechanisms • Earthquakes, Volcanoes and Plate Tectonic History of the Appalachians Tectonic Hazards: Types, Origins, Prediction • Earthquakes • Tsunami • Volcanoes
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics
• Schedule and Format • 7 lectures 9:00-11:15 am Friday • March 28 – May 16. • Field trip April 11 (2wks): Asheville Geology: Interior of a plate collision and ancient earthquakes (faults) • Lecture format: Powerpoint slides and videos • Will post powerpoints on course webpage after lectures in pdf format • Ask questions if unclear (including jargon) – not enough time for extended discussion.. After class, email
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics
• Instructor Biography • Geology degrees: B.A Colgate U., M.Sc. and Ph.D, U of Massachusetts at Amherst • 2 years teaching geology to undergraduate and graduate students, SUNY Oneonta • 1 year research NY State Geological Survey • 30 years petroleum geology with ExxonMobil; exposure to global geology; teaching company schools • Research and project coordinator for Exxon Tectonic Map of the World, 1981-1985 • Published abstracts and papers; Labrador, Adirondacks, Nigeria, Caribbean/GOM, China
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics
• Course Outline • Introduction: Course Objectives, Outline, Basics of Plate Tectonics and Geology (Rock Types and Geologic History) • Earth’s Interior: Structure, Composition, and Temperature • Plate Tectonics and Continental Drift: Theory, Data, Mechanisms • Earthquakes, Volcanoes and Plate Tectonic History of the Appalachians • Tectonic Hazards: Types, Origins, Prediction • Earthquakes • Tsunami • Volcanoes
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics DEFINITIONS, Wikipedia Geology (from the Greek γῆ, gê, "earth" and λόγος, logos, "study") is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change.
Earth Topography and Bathymetry
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Plate Tectonics - scientific theory that describes large-scale motions of Earth’s lithosphere (brittle outer shell of Earth). Model builds on concepts of continental drift and sea-floor spreading
Earth’s Plates
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Continental Drift - the movement of Earth’s continents relative to each other by appearing to drift across the ocean bed (USGS); from early 20th C. (originally 16th C.)
Continental Drift - Pangaea
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Lithosphere and Plate Boundaries – Lithosphere is the rigid outermost shell of Earth divided into 8 major plates and several minor plates. Up to 10,000,000 km2 area. EARTH’S MAJOR PLATES
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Lithosphere and Plate Boundaries – Lithosphere is the rigid outermost shell of Earth divided into 8 major plates and several minor plates. Up to 10,000,000 km2 area. EARTH’S MAJOR PLATES
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Lithosphere and Plate Boundaries. Plate thickness: 10-200 km. Where plates meet, their relative motion determines the type of plate boundary: convergent, divergent, or transform.
PLATE
PLATE PLATE
Transform (strike-slip)
Divergent
Convergent
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Lithosphere and Plate Boundaries – Earth’s plate boundary types: divergent, convergent, and transform EARTH’S MAJOR PLATES
Divergent boundary Convergent boundary Transform boundary
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Sea-Floor Spreading – a process occurs at mid-ocean ridges where new oceanic WHAT PROCESSES DRIVE that PLATE TECTONICS AND CONTINENTAL DRIFT? crust is formed through volcanic activity and then gradually moves away from the ridge. Sea-Floor Subduction Helps to explain continental drift.Spreading Occurs and at divergent plate boundaries where plates separate (from 1950’s-60’s).
Mid-Atlantic Ridge
East Pacific Rise Sea-Floor Spreading
Mid-Ocean Ridge
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate and sinks into the mantle as the plates converge.
Subduction Zone
Subduction Zone
Subduction Zone
Oceanic Trench and Volcanic Arc
Sea Floor Spreading, Subduction and Megathrust Earthquakes https://www.youtube.com/watch?v=f-nIb8JkFrg
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Plate Boundary Characteristics –Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.[2]
Andes
Mt. Everest
Aleutian Trench
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics DEFINITIONS, Wikipedia Earthquake – result of a sudden release of energy in Earth that creates seismic waves. From Merriam Webster: Sudden shaking of the ground caused by a disturbance deeper within the crust (or mantle) of the Earth. Most earthquakes occur when masses of rock straining against one another along fault lines suddenly fracture and slip. Tsunami – a series of water waves caused by displacement of large volume of water, an ocean or large lake; associated with earthquakes, volcanic eruptions, landslides, glacier calvings, meteorite impacts and other disturbances Volcano – opening or rupture in planet’s crust which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface.
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics •
Introduction to Rock Types •
Sedimentary • Deposited at surface by water, wind or ice • Deposition clastic, biological, or chemical • Layered (beds) • Law of superposition • Sandstone, shale, limestone
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics •
Introduction to Rock Types •
Igneous • Crystallized from molten rock ( magma) • Volcanic – near surface: lava, ash, basalt, andesite, rhyolite • Intrusive – at depth: crystal visible to eye – granite
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics •
Introduction to Rock Types •
Metamorphic – Greek: change form • Modified by temperature pressure and deformation • Quartzite, marble, slate, schist, gneiss • Folded and faulted with secondary layering (foliation)
Geology Kitchen: 3 types of Rocks https://www.youtube.com/watch?v=pg_jKJFbA2A
1/1 Precambrian Eon: Earth Forms 4600 Ma 1/15 Oldest Rocks 4400 Ma 2/25 First Cells 3900 Ma bluegreen algae 3/20 Oldest Fossils (Algal Mats) 3600 Ma 7/17 Cells with Nuclei 2100 Ma
GEOLOGIC TIME: HISTORY OF THE EARTH AS CALENDAR YEAR
Earthhttp://www.timetoast.com/timelines/63215 History in 24 Hours: http://geofaculty.uwyo.edu/heller/SedMovs/GeologicTime.html
GEOLOGIC TIME: HISTORY OF THE EARTH AS CALENDAR YEAR Mammals End Dinosaurs
1st Dinosaurs 11/18 End Precambrian, Paleozoic/544 Ma; Marine invertebrate explosion 11/22-28 Land Plants Fish 500-400 Ma 12/1 Insects 385 Ma 12/5 Reptiles 330 Ma 12/13 Dinosaurs 228 Ma 12/14 Mammals 12/22 Flowers 115 Ma 12/26 Dinosaurs extinct 66 Ma (13 days or 162 My)
Reptiles Insects Fish, Plants
Marine Invertebrates
Earthhttp://www.timetoast.com/timelines/63215 History in 24 Hours: http://geofaculty.uwyo.edu/heller/SedMovs/GeologicTime.html
GEOLOGIC TIME: HISTORY OF THE EARTH AS CALENDAR YEAR
12/28 – Primates 39 Ma 12/31 7:36 AM Human-like animals 4 Ma (Genus Homo) 12/31 11:48 PM Homo Sapiens 0.1 Ma (12 mins!!) 12/31 11:59 Pm Revolutionary War 1776 Birth of USA Earthhttp://www.timetoast.com/timelines/63215 History in 24 Hours: http://geofaculty.uwyo.edu/heller/SedMovs/GeologicTime.html (80 year life ½ sec)
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Deciphering Geologic History: Relative Age, Absolute Age, Law of Superposition Law of Superposition
RELATIVE AGE Relative age younger Fossil-bearing sedimentary rocks can be correlated
Relative age older 1.7 By
Law of Superposition: Sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top. The law was formulated in the 17th century by the Danish scientist Nicolas Steno. (Wikipedia)
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Deciphering Geologic History: Relative Age, Absolute Age, Law of Superposition ABSOLUTE AGE
1.7 By Absolute age derived from radioactive isotope abundances
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Deciphering Geologic History: Radioactive Minerals in Igneous Rocks and Absolute Age •
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ABSOLUTE AGE (Radioactive) DATING: Age dating of rocks based on relative abundance of radioactive isotope and its daughter product based on known radioactive decay rate. Radioactive decay: process whereby nucleus of an unstable atom loses energy by emitting radiation (alpha, beta, gamma)
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Rate of radioactive decay is constant for radioactive isotope (U, Th, Rb, K, C)
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Half-life is time it takes to produce 50% daughter product Measure relative amounts of radioactive parent and stable daughter isotopes, determines time since crystal formed and started radioactive decay.
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Zircon with U
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Deciphering Geologic History: Cross-cutting relations, Relative and Absolute Age
gneiss
Cross-cutting relations: igneous granite (white) is younger than metamorphic gray gneiss because it cuts across the layering in the gneiss (relative age of granite younger than gneiss). Absolute age of granite and gneiss can also be determined by dating of radioactive isotopes in rocks.
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics Unconformity is a surface of non-deposition or erosion separating two rock masses of different ages with missing deposits, indicating that sediment deposition was not continuous Formation of an Unconformity 540 My 540 My
700 Ma
Angular unconformity
1700 Ma 1700 Ma
Columnar Section Grand Canyon
540 My
Angular unconformity
700 Ma
UNCONFORMITIES Grand Canyon
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics FAULTING; SIGN OF DEFORMATION AT PLATE BOUNDARIES – 3 TYPES OF FAULTS Strike-slip Fault
Normal Faults
Reverse (thrust) Fault
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics FOLDING; SIGN OF CONVERGENT MARGIN PLATE TECTONICS Rock Deformation: Folded Sedimentary Rocks anticline syncline syncline
anticline
Pa Valley and Ridge; Folded Appalachians
Boats for scale
Italy, Cinque Terra Mt. Pisgah NC top, Blue Ridge
< 1meter
Rock Deformation: Folded Metamorphic Rocks Colorado Precambrian RMNP
Greenland Caledonides
Chimney Rock, Blue Ridge
10’s of kms A few meters
Earthquakes, Volcanoes, Tsunami, and Plate Tectonics
• Course Outline • Introduction: Course Objectives, Outline, Basics of Plate Tectonics and Geology • Earth’s Interior: Structure, Composition, and Temperature • Plate Tectonics and Continental Drift: Theory, Data, Mechanisms • Earthquakes, Volcanoes and Plate Tectonic History of the Appalachians • Tectonic Hazards: Types, Origins, Prediction • Earthquakes • Tsunami • Volcanoes