Plate Tectonics Slides PDF

# Plate Boundaries - Contrast continental and oceanic crust, as well as the lithosphere and asthenosphere - Explain the mechanisms driving movement of lithospheric plates (convection, ridge push, slab pull) - List and describe the relative direction of plate motion for the three types of plate boun...

# Plate Boundaries - Contrast continental and oceanic crust, as well as the lithosphere and asthenosphere - Explain the mechanisms driving movement of lithospheric plates (convection, ridge push, slab pull) - List and describe the relative direction of plate motion for the three types of plate boundaries - Provide real world examples of each type of plate boundary - Draw cross sections of divergent and convergent plate boundaries - Explain how scientists determine the speed of plate motion and provide a range of measured plate speeds ## Quick Review Before we begin, let's quickly review what we have already covered: - Earth's interior is hot - Earth's structure is layered. - The outer layer of Earth is broken into pieces that are moving. ## Earth's Layers - **Lithosphere:** Crust + uppermost mantle = tectonic plate - **Asthenosphere:** Layer in mantle (hot and weak solid) ## The Crust - Continental crust is less dense than oceanic crust - Continental crust is granitic - Oceanic crust is basalt ## Tectonic Plates An image of the tectonic plates is displayed. ## Plate Motion - Lithosphere - Asthenosphere and lower mantle - Convection - Ridge - Trench - "Slab pull" ## Plate Motion - Slab Pull An image of a cross section of the Earth displays how the "slab pull" mechanism works. ## Plate Boundaries An image of a cross section of the Earth displays the 3 types of plate boundaries: - **Convergent plate boundary** - **Transform plate boundary** - **Divergent plate boundary** ## Divergent Plate Boundaries - A series of images shows how the mid-ocean ridge forms as a divergent plate boundary. ## Rift Valley - An image of the east african rift valley is displayed. ## Mid-Ocean Ridges - AKA Spreading Centers - Most extensive chain of mountains on Earth - Magma fills fissures in seafloor and solidifies - Little erupts onto the seafloor as lava unless spreading is very rapid ## East Pacific Rise - Fast-spreading (10s of cm/yr) - Gentle slopes - East Pacific ## Mid-Atlantic Ridge - Slow-spreading (a few cm per year) - Steep slopes - Mid-Atlantic ## Activity - **Sketch a cross section through a divergent plate boundary.** - **Label:** Type, crust mantle, lithosphere, and asthenosphere. ## Here's mine: A hand drawn image of an attempt at drawing a cross section of a divergent plate boundary. ## Convergent Plate Boundaries An image of 3 cross sections of the Earth shows the 3 different types of convergent plate boundaries: - **Ocean - Continent** - **Ocean - Ocean** - **Continent - Continent** ### 1 - Oceanic-Continental Convergence - Ocean plate is subducted - Continental arcs generated - Explosive andesitic volcanic eruptions ### 2 - Oceanic-Oceanic Convergence - Denser plate is subducted - Deep trenches generated - Volcanic island arcs built ### 3 - Continental-Continental Convergence - Subduction ceases - Tall mountains uplifted - Himalayas from India-Asia collision ## Activity - **Sketch a cross section through a convergent plate boundary.** - **Label:** Type, crust, mantle, lithosphere, and asthenosphere. - **Use arrows to indicate plate motion.** ## My Convergent Boundary Sketch A hand drawn image of an attempt at drawing a cross section of a convergent plate boundary. ## Transform Boundary Features - **Offsets oriented perpendicular to mid-ocean ridge** - **Segments of plates slide past each other** - Permit mid-ocean ridge to move apart at different rates - **Shallow but strong earthquakes** An image of a transform plate boundary is displayed. ## Transform Fault Margins An image of a transform fault and a map of the San Andreas Fault are displayed. ## Plate Motion An image of the Earth displays the plates with their velocities in mm/year. Plate velocities are on the order of cm to 10s of cm per year. ## Online Velocity Viewers A link to a website where you can view plate velocities online is displayed. ## Future World + 50 Ma An image of the Earth shows how it will look in 50 million years. ## Examples of Plate Boundaries A table is displayed that shows features, tectonic processes, and examples of the 3 different plate boundary types: - **Divergent Plate Boundaries** - **Convergent Plate Boundaries** - **Transform Plate Boundaries**