Layers of the Earth
Name the outermost layer of the Earth
Crust
Tectonic plates at divergent boundaries are moving ___________ from each other
Tectonic plates at convergent boundaries are moving ___________ each other
towards
Tectonic plates at transform boundaries are _________ past each other
Sliding
Identify the scientist who proposed the theory of continental drift
Alfred Wegner
Name the second layer of the Earth
Mantle
Divergent boundaries are also called _____________ boundaries
Constructive
Convergent plate boundaries are also called __________ boundaries
Destructive
Transform plate boundaries are also called __________ boundaries
Conservative
Describe the theory of continental drift
The theory of continental drift states that the Earth’s crust is split into different plates which slide across the asthenosphere.
Name the third and fourth layers of the Earth
Inner core and outer core
Describe the process of new sea floor formation
New sea floor is created when magma rises up through the gap left from the plates moving apart and solidifies
Identify the two different types of convergent boundaries
Subduction and collision
List ways how scientists are working to reduce the devastation caused by Earthquakes
Engineering
Warning systems
Monitoring of tectonic plates
fossils of plants and animal found on continents where they don't live, continents fit together like a jigsaw, unique rock deposits found on multiple continents
Identify which is thicker: continental or oceanic crust
Continental crust
Describe the geological features that form at divergent boundaries
Mid ocean ridges, rifts and volcanoes
Describe the geological features that form at collision convergent boundaries
Collision - mountain ranges from two continental plates pushing together
Explain how an earthquake occurs
As the plates slide past each other sections get ‘stuck’. Over time this causes pressure and energy to build up in the ‘stuck' areas. Eventually, the pressure build-up gets so much that the plates ‘slip’ / jolt past each other releasing energy.
Convection currents in the mantle - hot mantle rises, cools then falls
Slab pull - older plates sink into the mantle creating subduction zones, pulling the rest of the plate with it
Ridge push - when warmer magma rises in the rifts (cracks) along the mid-ocean ridges it forces the cooler, denser sea-floor to slide sideways, pushing the plates away from each other.
True or false:
The lithosphere consists of the upper layer of the mantle and the crust. The asthenosphere consists of the rigid lower layer of the mantle
True
Describe convection currents in the mantle. Identify an issue with using convection currents to as the main explanation of plate movement at divergent boundaries
Heat from the Earth’s core warms rock lower down in the mantle causing it to expand. This makes the rock become less dense and rise towards the surface. When the rock hits the solid lithosphere at the top it spreads out. As the rock spreads out it cools back down causing it contract, become denser and sink back down to again be reheated as part of a cycle.
Issue: scientists have not found convection currents big enough to solely drive plate movement
Describe the geological features that form at subduction convergent boundaries
Subduction - deep ocean trenches and volcanos from the oceanic plate sinking under the continental plate and melting
Explain why mountain ranges and volcanos aren't formed at transform boundaries
Identify who discovered sea floor spreading and explain how this supported Alfred Wegner's theory
Harry Hess. This support continental drift as it showed that new sea floor is being created and therefore the ocean is widening and the continents are moving