Essentials of Oceanography Chap 2 Flashcards
What is magnetic dip
The degree to which a magnetite particle
points into Earth
Relation of magnetic dip and latitude
Higher latitudes experience higher magnetic dip
How can we use paleomagnetism to find the original latitude a rock originated from
By looking at the magnetic dip, we can indicate the latitude the rock formed from
Where is sea floor spreading the greatest
Pacific
Difference between slopes of mid-ocean ridges that spread fast and slow
Slowly spreading mid-ocean ridges often have steeper slopes due to increased cooling periods and Quickly spreading mid-ocean ridges often have gentle slopes due to decreased cooling periods
What is an oceanic rise
gently sloping and fast-spreading mid-ocean ridge.
What is the difference between Oceanic Rises and Oceanic Ridges
Rises are fast spreading, ridges are slow.
relation of mid-ocean ridge spreading rate and earthquake size
A mid-ocean ridge with a faster spreading rate generally produces smaller earthquakes compared to a slow-spreading ridge
Volcanoes at Continental-Oceanic Convergent zones lead to what type of volcanic arc
Continental arc with intermediate composition
Volcanoes at Oceanic-Oceanic Convergent zones lead to what type of volcanic arc
Island Arc with Basaltic composition
Are earthquakes at spreading centers shallow or deep
Shallow
Are earthquakes at subduction zones shallow or deep
Deep
Why do earthquakes at subduction zones form so deep
1.Brittle fracturing(due to oceanic plate staying cold)
2. Stress accumulation(due to bending, stretching, and compression)
3.Phase Changes in minerals(minerals transforming into denser minerals can suddenly release energy and trigger deep earthquakes.)
4.Water trapped in minerals within the subducting plate is released due to high pressure and temperature which weakens the plate and can lead to deep earthquakes.
where do ALL transform faults form
between two segments of a mid-ocean ridge
3 stages of development in coral reefs
Fringing, Barrier, Atoll
What are Fringing Reefs
First stage of development in a coral reef, where reefs develop along the margin of a landmass where the temperature, salinity, and turbidity of the water are suitable for reef-building corals.
What are Barrier Reefs
Second stage in development where the reef is a linear
or circular reefs separated from the landmass by a well-developed lagoon. The reef grows upward as the island or landmass subsides.
What are atoll reefs
Final stage of reef development where the island or landmass completely submerges due to erosion and subsidence, leaving behind a ring-shaped reef surrounding a central lagoon
Where do Coral Reefs form
The corals require a solid surface to settle on, often found on the new volcanic islands formed.
What is a terrane
crust fragment formed on a tectonic plate and accreted or “sutured” to crust lying on another plate.
What is western North America
Terrane, its crustal material sutured onto the American Plate
What is the Wilson Cycle
a model that describes the opening and closing of ocean basins
What are the different stages of Wilson Cycle
Embryonic(Uplift), Juvenile(Spreading), Mature(Spreading), Declining(Convergence), Terminal(convergence and uplift), Suturing(Convergence and Uplift).
