Introduction and ocean basins Flashcards
What percentage of the world’s oxygen is provided by the ocean?
About half of the world’s oxygen
This is primarily due to photosynthesis by phytoplankton, mangroves, seagrass, and green algae.
What is the primary composition of continental crust?
Granite
What is the primary composition of oceanic crust?
Basalt
What layer of the Earth does the lithosphere float on?
Asthenosphere
What geological feature is formed when tectonic plates move apart?
Oceanic ridges
What geological feature is formed when tectonic plates come together?
Trenches
Fill in the blank: The crust and upper part of mantle is broken into _______.
Tectonic plates
What process causes sea-floor spreading?
Two plates moving away from each other
What is the main result of plate collisions in tectonics?
Formation of deep trenches
What is the term for the geological activity concentrated at mid-ocean ridges and boundaries?
Geological activity
What are the three main parts of continental margins?
- Continental shelf
- Continental slope
- Continental rise
What is the biologically richest part of the ocean?
Continental shelf
What is the depth range of deep-ocean basins?
3000-5000 metres deep
What is the relatively flat region of the deep-sea floor called?
Abyssal plain
True or False: The continental rise is where sediments build up at the base of the continental slope.
True
What are the features found on the deep-sea floor?
- Submarine channels
- Low abyssal hills
- Plateaus
- Rises
- Seamounts
- Volcanic islands
What role does the ocean play in regulating the planet’s climate?
Regulates the planet’s climate
What is the process called that allows magma to come up and push tectonic plates apart?
Sea-floor spreading
Fill in the blank: Continental margins of ocean basins might be considered _______ or passive.
Active
