Submarine Continental Shelf Slopes and Fans Flashcards
1
Q
Nearshore Processes:
A
- Waves
- Lots of cross beds, well sorted, varying grain size
2
Q
Midshelf processes
A
- sediment settling and biologic processes
- Muds mixed by organisms living there
3
Q
Slope
A
- Slumps and turbidity currents (has canyons, channels and open slope)
- convolute beddings from slumps and normally graded bedding from turbidity currents
4
Q
Offshore Transition:
A
- Between Storm and fair weather wave bases
- size of orbitals - water velocity
- sediment settling out at most times but occassionally reworked by storms
- Hummocky cross stratification - big dunes formed in storms
- Depends where you are in the region - close to fair weather base = steep hummocks
5
Q
Canyons:
A
- If canyons come close to the shoreline, it will intercept the sands
- if it is near the middle, than it will only have mud/shells
- Behave as a drainage systems (if close to shoreline they may intercept the longshore currents so sediment gets fed down canyon or channel -> sediment is no longer near the shore to be worked by waves
- Sediment ends up on abyssal plain - alluvial fans with shallower slopes
- slumps on slopes as canyons hit the shallower slopes, velocity decreases and the sediment is deposited
6
Q
Submarine Fan
A
- Submarine fan at base of canyon
- base of slope at canyon mouth -> forming submarine fan
- Fan shaped because of avulsion - river dominated (coarsest material at canyon mouth)
- Going to deposit at the channel mouth -> makes the slope even less steep until it is easier for the river to go on a steeper slope.
- Turbidity currents so all the beds are normally graded
- channels are really obvious in rock records (less obvious if muddier)
7
Q
Submarine slumps on continental slope
A
- convolute bedding
- slumped turbidite beds
- blocks of turbidities, normally graded beds inside, mixed up muds over the top of the flat laid bedding of muds and turbudites
