Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Sedimentology and Stratigraphy > (T?) Storms and Ocean Currents > Flashcards

(T?) Storms and Ocean Currents Flashcards

1
Q

What is the name for the marine zone which exists to the edge of the continental shelf?

A

Neritic zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the name of the point between the bathyal zone and the neritic zone?

A

Shelf edge break

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the name for the marine zone which exists from the edge of the continental shelf to the abyssal plain?

A

The Bathyal zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What would the standard ratio for a typical continental shelf slope (range)

A

1:40 to 1:1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How far out can continental shelves go? (range)

A

10’s - 100’s km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How steep is the continental slope? (range)

A

2 - 7 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the name for the point where the bathyal zone meets the abyssal zone?

A

Continental rise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the name for the marine zone which exists beyond the bathyal zone?

A

Abyssal zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where does the transition between oceanic and continental lithosphere begin?

A

Continental rise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the expected depth of the shelf edge break?

A

200m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the expected depth of the continental rise?

A

400m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the primary difference between a epicontinental sea and a normal ocean?

A

Epicontinental seas exist on continental crust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give an example of an epicontinental sea

A

Gulf of Carpentaria - Inlet of Arafura Sea at the top of Australia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the “Hadal Zone”?

A

The marine zone below 4000m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the name for the marine zone beneath 4000m

A

Hadal zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the four devisions in the netric zone?

A

Foreshore, Shoreface, Off-shore transition, Offshore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the name for the zone between mean high water and mean low water?

A

Foreshore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the name of the zone between the mean low water and the fair weather base?

A

Shoreface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the name of the zone between the fair weather base and the storm weather base?

A

The Offshore Transition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the name of the zone below the Offshore Transition?

A

Offshore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What defines the foreshore?

A

Mean high water and mean low water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What defines the shoreface?

A

Zone between mean low water and fair weather base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What defines the off-shore transition?

A

Zone between the fair-weather base and the storm weather base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What defines the offshore zone?

A

Zone below the storm-weather base

25
Q

What is a typical range of depths for the fair-weather base?

A

~5 - 20 m

26
Q

What is a typical range of depths for the storm-weather base?

A

~20 - 200 m

27
Q

What is the likley scenareo where the storm-weather base is up to 200m deep?

A

Shelf boarders an ocean with larger fetch for storm waves

28
Q

What is a typical windspeed in a storm?

A

> 100km/hr

29
Q

What are the three components of the storm effect on shelf environments?

A

Wind drive currents deeper, high energy = sed into suspension, gravity driven underflow producing tempestites

30
Q

What are tempestites?

A

A rock which shows evidence of a strong storm because it has redeposited pre-existing sediments

31
Q

What does tsunami mean in Japanese?

A

Harbor Wave

32
Q

What is the typical range for the periods of a tsunami?

A

10^3 - 10^4 seconds

33
Q

Theoreticaly, what should a tsunami deposit show? (2)

A

Poorly mixed debris and fauna from various coastal/shallow marine sources

34
Q

What does “geostrophic” mean?

A

Windblown currents

35
Q

Why are the effects of geostrophic driven currents most noticable in deeper waters?

A

Tides, waves and storms mask the effects in shallower environments

36
Q

What is the main sedimentary action of geostrophic currents?

A

Moving fine sediment in suspension

37
Q

How is the upwelling in the thermohaline important for sedimentology?

A

High nutrience and thus high biogenic activity

38
Q

What does authogenic mean?

A

A mineral/sedimentary rock which is generated where it is found - i.e. not deposited

39
Q

What is Glauconite and how does it form?

A

Potassium rich mica (dark green mineral) which is authogenic, and crystalizes in a sedimentary environment

40
Q

What are the four materials which contribute to glauconitisation?

A

Hard parts of forams, Carbonate fragments, Faecal pellets, lithic fragments

41
Q

What macroenvironment is required for glauconitisation? What depth is this?

A

Interface between oxidising seawater and reducing intertidal waters, Typically 50-500m depth

42
Q

What zone does glauconitisation usually occur within?

A

Between the Neritic Zone and the Bathyal Zone

43
Q

What is glauconite a reliable indicator of? (3)

A

Shallow marine, Sedimentation of other material is slow, Usually precip in periods of sea level rise

44
Q

Why is glauconite particullary useful when determining dates of sea level rise?

A

Potassium can be radiometrically dated

45
Q

What is the bulk composition (>15%) of phosphorites?

A

P2O5

46
Q

Where does the majority of the phosphate come from in phosphorites? (3)

A

Primary bioclasts: Fish teeth, Scales, Vertebrete bones

47
Q

Aside from primary bioclasts, how else can phosphorites form?

A

Authogenic - grains of peloids and micronodules on sea floor

48
Q

What is the presence of phosphorites a characteristic sign of?

A

Slow sedimentation, hence it is found in condensed sections

49
Q

Where are phosphorites most commonly found in modern times?

A

Regions of continental margins with upwelling of nutrient rich waters (Plankton blooms)

50
Q

Give an modern example of a location with abundance of phosphorites

A

W. African coast from Antarctic waters

51
Q

When in geological history is it expected that phosphorite concentrations were at their greatest and why?

A

When sea level was at its highest and supply of other sediment to she shelf is reduced

52
Q

What is another name for pelagic sediment and what % carbon does it contain?

A

1-15% organic carbon, Black shale

53
Q

What is often found in the same environment as black shale?

A

Pyrite (Iron sulphate)

54
Q

How does black shale form?

A

Organic material falling to the sea floor, may become oxygenated by currents, falls into an anoxic environment

55
Q

What are the three characteristics which determine the formation of black shale?

A

Organic imput, breakdown by microbial activity, dilution of additional materials

56
Q

What is a good modern example of black shale formation?

A

The Black Sea

57
Q

What is required for Black Shale formation even when circulation on shelves is effective?

A

Supply of material needs to be greater than the rate of breakdown

58
Q

Why is black shale so important today?

A

Hydrocarbon source

Sedimentology and Stratigraphy (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions