lecture14spring2009 - Astronomy100Dr.Rhodes Lecture Chapter...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Astronomy 100 - Dr. Rhodes Lecture #14 - 2/18/2009
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter 6: The Earth-Moon System Plate Tectonics Plate Tectonics German meteorologist Alfred Wegener is credited with developing in 1910 the idea of continental drift — the gradual motion of the continents relative to one another. The Earth’s crust and the outer 40 miles of its mantle comprise the lithosphere , which is broken into about 12 tectonic plates . A rift zone is a place where tectonic plates are being pushed apart, normally by molten material being forced up out of the mantle.
Image of page 2
Alternative View of Parts of Earth’s Interior in which the Outer Mantle and the Crust are Called the Lithosphere and Asthenosphere
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Chapter 6: The Earth-Moon System The Mid-Atlantic Ridge One such rift zone runs down the spine of a undersea mountain range that is located roughly halfway between Europe and the U.S. and halfway between Africa and South America. This range is called the Mid- Atlantic Ridge . The observations associated with this Mid- Atlantic Ridge are what finally convinced geophysicists that Wegener was right, e.g., the Ridge is hot and earthquakes do occur there.
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter 6: The Earth-Moon System Sea-Floor Spreading Where the warm magna that is rising within the mantle reaches the Earth’s surface, it must stop flowing vertically and must begin to flow horizontally. This horizontal motion of the ocean floors is called sea-floor spreading . Because of this spreading Africa and South America have been separating for 150 million years and the oldest sea floor rocks are those near both continents.
Image of page 6
Chapter 6: The Earth-Moon System Subduction Zones and Convection Where a denser sea floor plate is sliding into the edge of a less-dense continental plate, the material in the sea floor plate dips into the Earth and slides beneath the continental plate. Such a location on the Earth is called a subduction zone .
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern