chapter 2

Question 1

Outline the theory of plate tectonics

Answer 1

• The lithosphere is made up of tectonic plates
• the plates float on the asthenosphere
• they float due to convection currents
• these currents are driven by density/heat

Question 2

State at least 3 pieces of evidence for the theory of plate tectonics

Answer 2

• Plates fit like puzzle pieces
• Fossil distribution
• Magnetic strips have alternate charges on the ocean floor
• Earthquakes & volcanoes
• Ocean floor surveys
• Satellites/GPS

Question 3

Describe the Coriolis effect and how it affects ocean currents

Answer 3

• it’s a force caused by the rotation of Earth
• it deflects currents to the right in the northern hemisphere and to the left in the southern hemisphere
• it has a greater effect at poles and less of an effect at the equator

Question 4

what’re the 3 types of plate boundaries and what they form

Answer 4

• convergent: trenches and volcanoes
• divergent: ridges, rifts, and volcanoes
• transform: nothing

Question 5

Explain how hydrothermal vents form at divergent plate boundaries

Answer 5

• Cold dense water seeps through the cracks in the seabed
• It is heated by the underlying magma , minerals from the lithosphere dissolve
• The superheated water/dissolved minerals becomes less dense and rise up to the seafloor
• Once it reaches deep cold water, it cools quickly
  the minerals then precipitate out of solution forming/building up the vent