Earth's Lithosphere and Internal Structure
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Questions and Answers

What is the thinnest layer of the Earth's internal structure?

  • Crust (correct)
  • Lithosphere
  • Core
  • Mantle

    • What is the term used to describe the base of the crust?

  • Lithospheric boundary
  • Asthenospheric layer
  • Mohorovicic discontinuity (correct)
  • Mantle-core boundary

    • What is the thickness of the Lithosphere?

  • 660 km to 1000 km
  • 100 km to 200 km
  • 50 to 300 km (correct)
  • 3 to 70 km

    • What is the term used to describe the strong outer layer of the Earth?

    <p>Lithosphere</p> Signup and view all the answers

    What is the term used to describe the layer that extends from the base of the Lithosphere to 660 km?

    <p>Asthenosphere</p> Signup and view all the answers

    What is the starting temperature of the Asthenosphere?

    <p>1300°C</p> Signup and view all the answers

    What is the term used to describe the layer that includes the lower part of the Lithosphere and the upper part of the Asthenosphere?

    <p>Upper Mantle</p> Signup and view all the answers

    How do we know the layers of the Earth's internal structure exist?

    <p>Through seismic data</p> Signup and view all the answers

    What is the region from the 410-km to the 660-km discontinuity known as?

    <p>Transition Zone</p> Signup and view all the answers

    What is the estimated temperature at the core-mantle boundary?

    <p>4500 ± 500 °C</p> Signup and view all the answers

    What is the composition of the Outer Core?

    <p>Mostly iron and nickel</p> Signup and view all the answers

    What is the temperature at the surface of the Inner Core?

    <p>5430 °C</p> Signup and view all the answers

    What is the Lithosphere composed of?

    <p>The crust and the upper mantle</p> Signup and view all the answers

    At what temperature do rocks in the Lithosphere take on a viscous nature and flow?

    <p>1300 °C</p> Signup and view all the answers

    What marks the boundary between the Lithosphere and the Asthenosphere?

    <p>A change in ductility</p> Signup and view all the answers

    How do we know the locations of the Lithosphere and Asthenosphere?

    <p>Through the study of earthquakes and seismic waves</p> Signup and view all the answers

    What is the Lithosphere composed of?

    <p>The crust and the upper part of the mantle</p> Signup and view all the answers

    What is the primary cause of the transfer of heat in convection?

    <p>Differences in temperature</p> Signup and view all the answers

    What is the process by which heat or electricity is directly transmitted through a substance?

    <p>Conduction</p> Signup and view all the answers

    How many major plates are the Earth's crust divided into?

    <p>12</p> Signup and view all the answers

    What is the term for the deformation of the crust as a result of plate interaction?

    <p>Tectonics</p> Signup and view all the answers

    What is the outer core primarily composed of?

    <p>Metallic fluid</p> Signup and view all the answers

    What is the main cause of the Earth's magnetic field?

    <p>The convection currents in the outer core</p> Signup and view all the answers

    What is the layer below the lithosphere?

    <p>The asthenosphere</p> Signup and view all the answers

    What occurs when two oceanic plates collide?

    <p>One plate overrides the other, forming a subduction zone</p> Signup and view all the answers

    What is the result of a collision between two continental plates?

    <p>Folding, faulting, and mountain building</p> Signup and view all the answers

    What is the term for the boundary where lithosphere is neither created nor destroyed?

    <p>Conservative boundary</p> Signup and view all the answers

    What feature is formed as a result of an oceanic plate being subducted?

    <p>Deep trench</p> Signup and view all the answers

    What is a characteristic of an island arc?

    <p>A chain of volcanic islands</p> Signup and view all the answers

    What is the result of a conservative plate boundary?

    <p>Production of faults</p> Signup and view all the answers

    What is the name of the deepest part of the ocean?

    <p>Mariana Trench</p> Signup and view all the answers

    What is a characteristic of a convergent plate boundary?

    <p>Collision of two plates</p> Signup and view all the answers

    What drives the movement of the plates?

    <p>The underlying hot mantle convection cells</p> Signup and view all the answers

    What is the main difference between oceanic and continental plates?

    <p>Their composition</p> Signup and view all the answers

    What is the process that occurs along the boundaries of a plate?

    <p>Deformation</p> Signup and view all the answers

    What type of plate boundary is characterized by plates moving away from each other?

    <p>Divergent Plate Boundary</p> Signup and view all the answers

    What is the term for the process by which new plate material is added to the lithosphere?

    <p>Seafloor spreading</p> Signup and view all the answers

    What is the typical width of ocean ridges?

    <p>3000-4000 km</p> Signup and view all the answers

    What is the characteristic of earthquakes that occur at divergent plate boundaries?

    <p>They are shallow and limited in magnitude</p> Signup and view all the answers

    What is the approximate percentage of the Earth's surface covered by oceanic plates?

    <p>71%</p> Signup and view all the answers

    Study Notes

    Earth's Internal Structure

    • Earth's internal structure is divided into three main parts: crust, mantle, and core.
    • Crust: 3-70 km thick, ranges from 3 km at oceanic ridges to 70 km in collisional orogens/mountains.
    • Mohorovicic discontinuity (Moho) defines the base of the crust.
    • Lithosphere: 50-300 km thick, includes the crust and uppermost mantle, thinnest in oceanic regions and thicker in continental regions.
    • Asthenosphere: extends from the base of the lithosphere to 660 km, characterized by high temperature and pressure, and viscous flow.
    • Upper Mantle: extends from the Moho to the 660 km discontinuity, includes the lower part of the lithosphere and the upper part of the asthenosphere.
    • Transition Zone: region from the 410 km to the 660 km discontinuity.
    • Lower Mantle: extends from the 660 km discontinuity to the 2900 km discontinuity at the core-mantle boundary.
    • Outer Core: extends from the 2900 km to the 5200 km discontinuity, composed of mostly iron and nickel.
    • Inner Core: extends from the 5200 km discontinuity to the center of the Earth, primarily a solid ball composed of an iron-nickel alloy.

    Lithosphere

    • Lithosphere is the outermost layer of Earth, composed of the crust and the brittle part of the upper mantle.
    • The term "lithosphere" is derived from the Greek words "lithos" (stone) and "sphaira" (globe or ball).
    • At the lithosphere-asthenosphere boundary, rocks take on a viscous nature and flow, albeit very slowly, due to high temperature and pressure.

    Plate Tectonics

    • Plate tectonics is the concept that the lithosphere is divided into a small number of nearly rigid plates that move over the asthenosphere.
    • The Earth's crust is divided into 12 major plates that move in various directions, causing them to collide, pull apart, or scrape against each other.
    • Each type of interaction causes a characteristic set of Earth structures or "tectonic" features.
    • The word "tectonics" refers to the deformation of the crust as a consequence of plate interaction.

    Plate Composition and Movement

    • Plates are made of rigid lithosphere, which is composed of the crust and the upper part of the mantle.
    • Below the lithosphere is the asthenosphere.
    • Plates are moved around by the underlying hot mantle convection cells.
    • The Earth's magnetic field originates in the outer core, which is a metallic fluid consisting mainly of iron.

    Convection and Conduction

    • Convection: the movement of fluid due to differences in temperature and density, resulting in the transfer of heat.
    • Conduction: the process of direct heat transfer through a material without movement.

    Oceanic and Continental Plates

    • Oceanic plates are formed at mid-oceanic ridges, composed of heavy rocks (mafic in nature), dense (approximately 3200 kg/m3), and old (less than 200 million years).
    • Continental plates are formed at subduction zones, composed of lighter rocks (felsic in nature), less dense (approximately 2600-2750 kg/m3), and older (up to 4 billion years).
    • Oceanic plates cover approximately 71% of the Earth's surface, while continental plates cover 29%.

    Plate Boundaries

    • There are three types of plate boundaries: divergent, convergent, and conservative.
    • Divergent plate boundaries: plates move away from each other, resulting in the creation of new plate material.
    • Convergent plate boundaries: plates move towards each other, resulting in subduction, collision, or destruction of plate material.
    • Conservative plate boundaries: plates slide past each other, resulting in faults and magma outflow.

    Convergent Plate Boundaries

    • Collision of oceanic plates: one plate subducts beneath the other, forming a subduction zone and trench.
    • Collision of continental plates: plates collide and push against each other, resulting in intense folding, faulting, and mountain formation.

    Conservative Plate Boundaries

    • Along conservative boundaries, lithosphere is neither created nor destroyed, and plates move laterally relative to each other.
    • Examples include the San Andreas Fault in California, USA.

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    Description

    This quiz covers the basics of Earth's internal structure, including the crust, mantle, and core. Learn about the importance of the lithosphere and how we know about the internal structure of the Earth.

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