question of the day question: list 4 pieces of evidence for plate tectonics. (use your notes!)...
TRANSCRIPT
Question of the DayQuestion of the DayQuestion of the DayQuestion of the Day
Question: List 4 pieces of evidence for plate tectonics. (Use your notes!)
Answer: … … …
Turn In:-Mystery of the Far Flung Fossils-p. 566 CYU’s 1 - 7
The Earth’s crust
• Can be classified into two types (continental & oceanic)
• Is split into smaller pieces called plates
• Plates sometimes run into each other
• Magma circulating in the mantle moves them around
Divergent Plate Boundary
• At a divergent plate boundary, two plates move apart
• Starts on land as a rift valley
• Ends up as a mid-ocean ridge (after millions of years)
Divergent Boundaries
• Locations:•Mid-Atlantic Ridge (Middle of Atlantic Ocean)
• East African Rift Zone
Convergent Plate Boundary
• Where two plates move together
• There are 3 types of convergent plate boundaries
Converging Oceanic/Continental
• An oceanic plate and a continental plate meet
• The denser oceanic plate sinks underneath the continental plate
• Called subduction
• Produces volcanoes on the continental plate
Converging Oceanic/Continental
• Locations– Washington and Oregon (Cascade Mountains)– Andes Mountains (South America)
Converging Oceanic/Oceanic
• Two oceanic plates meet
• The oceanic plate with older crust is colder so it is – A. Less Dense– B. Denser– C. Thicker– D. Hotter
Converging Oceanic/Oceanic
• Two oceanic plates meet
• The oceanic plate with older crust is colder so it is – A. Less Dense– B. Denser– C. Thicker– D. Hotter
Converging Oceanic/Oceanic• It subducts underneath the less dense plate
• Volcanoes form on the upper plate– Draw this:
Converging Continent/Continent
• Two continental plates with the same density meet
• True or False: – Subduction can occur?
• FALSE!
– Volcanoes can form?• FALSE!
– Mountains form?• TRUE!
Hot Spots
• Occur in the middle of plates (not a plate boundary)
• Very hot area of mantle (Mantle plume) melts through the crust
• Stationary (never move)
• As plate moves, mantle plume will melt several holes in the crust, forming a chain of volcanoes