L5 - Margins and Mechanisms Flashcards
1
Q
What should I include on a diagram of a passive margin?
A
- Continental & Oceanic plates
- Land > Shelf > Slope > Rise > Abyssal Plain
- Submarine canyon
- Turbidite
2
Q
Describe characteristics of passive margins
A
- Slowly moving away from mid-ocean spreading centre
- No orogeny
- Low seismic activity, no volcanism
- Thick sediment deposits and old oceanic crust
3
Q
What is the maximum height, width, depth and speed of a Turbidite?
A
- 120m high
- 650km long
- 7km wide
- Travel at 60km per hour
4
Q
Sediment layering on the ocean floor is caused by what process
A
- Turbidites - Heavier, courser material settles to the bottom, lighter material settles over the top
- Thus two layers per Turbidite
5
Q
Where are passive margins found?
A
- Found on continent bearing tectonic plates
- Passive margins are zones where continental and oceanic lithosphere meet but which aren’t plate boundaries
6
Q
What hydrocarbon is often found buried amidst ocean sediment at passive margins
A
Gas hydrates
7
Q
What is a aulacogen?
A
The failed arm of a triple junction
