Earth's processes and plate tectonics Flashcards
What was Pangea?
This is when all of the continents were together as a big mass.
What’s the difference between the rigid lithosphere and the plastic asthenosphere?
The asthenosphere flows where as the lithosphere bends when a load is applied.
What is a divergent boundary?
This is when the plates move apart - this is perpendicular to the continental crust and we can see flault scarps that form steps when faults cut across the land surface.
What are convergent boundries?
These are when tectonic plates move together via subduction. This is how volcano’s can form.
What are transform boundries?
These are when tectonic plates slide sideways - this is how earthquakes can occur.
What evidence do we have for earths magnetic field?
We can look at igneous lava flows and see that they’re magnetic.
Evidence for the flip in polarity of earth’s magnetic field?
We can observe the symmetrical polarity pattern found in the oceaic crust. This crust is formed though sea floor spreading - the oceanic crust speads outwards and new oceanic crust is formed.
Where do convection cells take place and what are mid ocean ridges?
Mid ocean ridges are mountain systems underwater caused by plate tectonics. Also, convection cells take place in the asthenosphere.
What are hotspots and in what boundary do these take place?
These are single points where magma pushes up through a single point - these occur at divergent plate boundries. The magma plume punches through the lithosphere and it forms a single volcano - can lead to dorment volcanoes as the plates move along the hotspot.
What term is used to describe the depth and shape of the sea floor?
Bathymetry.
What happens to the lithosphere and the asthenosphere when a load is placed on top of the lithosphere?
The lithosphere will bend it’s base down in to the plastic asthenosphere which will flow out of the way.
