Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GEOL200 > Week 8: Tides and coastlines > Flashcards

Week 8: Tides and coastlines Flashcards

(63 cards)

Start Studying
1
Q

What is a tide?

A

Periodic short-term changes in height of ocean surface caused by the combination of the gravitational force of the Moon and the Sun and motion of the earth

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

Are tides a wave?

A

Yes, a huge one
- wavelength 1/2 of the earth’s circumference

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

What do tides need to keep moving?

A

Needs to remain under the influence of the force that created it gravity

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

What causes tides?

A

Gravitational pull of moon and sun acting on the ocean and the earth’s rotation

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

Sun vs moon

A

The sun has half the role of the moon on tides

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

What is the barycentre?

A

The centre of mass of two orbiting bodies
** earth-moon system revolves once a month (27.3 days) around centre of mass

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

Newton’s law of universal gravitation

A

Every object that has a mass in the universe is attracted to every other object
- if mass increases, gravitational force increases
- if distance increases, gravitational force decreases

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

Centripetal forces

A

Required to keep identical sized particles in identical-sized orbits as the result of the rotation of the earth-moon system around barycentre
**all arrows equal and same direction

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

Resultant forces

A

What generates tides
Two vectors (gravity and centripetal force)- diff btwn them creates 2 bulges of water

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

Tidal bulges

A

Earth rotates under the water bulges

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

How long does it take for a full tidal cycle?

A

24 hours and 50 min

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

Lunar bulges

A

Moon revolves around earth is same direction as earths rotation
Takes an extra 50 min for earth to catch up to moon

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

Lunar day

A

Time of day when the moon is highest in the sky and the next time of day when is is at its highest again

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

Role of the sun

A

Creates 2 solar bulges

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

Spring tide

A

Tide of max range
Occurs every 2 weeks when moon is in new or full moon phase
**greatest gravitational attraction bc moon, sun and earth are all in alignment
**coastal flooding and storm surge

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

Neap tide

A

Tide of minimal range
Occurs every 2 weeks when moon is in 1st quarter or 3rd quarter phase (7 day after spring tides)
**low gravitational attraction bc moon and sun are at right angles

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

What are the three tidal patterns?

A
  1. Diurnal
  2. Semidiurnal
  3. Mixed semidiurnal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Diurnal

A

1 high tide, 1 low tide
ex. gulf of mexico

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

Semidiurnal

A

2 high, 2 low (equal heights)
ex. atlantic coast

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

Mixed semidiurnal

A

2 high, 2 low (unequal heights)
ex. pacific coast

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

Tidal range

A

Vertical diff btwn consecutive high and low tides

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

Macrotidal

A

> 4 m

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

Mesotidal

A

2 to 4 m

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

Microtidal

A

<2 m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Greatest tidal range in the world and why?
Bay of Fundy (15-17m) Basin shape is restricted
26
Two ways to explain tides
1. Equilibrium theory of tides 2. Dynamic theory of tides- Amphidromic circulation
27
Equilibrium theory of tides
Ignore ocean basins and coastlines, ocean that covers entire earth
28
Dynamic theory of tides
More complex situation- continents, coastlines, coriolis effect, water depth etc.
29
Amphidromic circulation
Water sloshes from left to right at side of basin Tide as rotary wave- moves around a central part **tide is a counterclockwise rotation in northern hemipshere
30
Amphidromic point
Locations where there are little or no tide in the ocean
31
Tidal flats- Mudflats
Coastal wetlands form in intertidal zone; submerges and emerges 2x day
32
Tidal currents
Caused by rise and fall in water as a tide crest approaches and passes
33
Flood current
Water moving towards land, rising water levels
34
Ebb current
Water moving away from land, falling water levels
35
Slack water
No movement either towards land or offshore
36
Tidal zones
1. Subtidal 2. Intertidal 3. Supratidal
37
Subtidal zone
Always underwater, below tide line
38
Intertidal zone
Tidal flat, exposed then submerged then exposed High biodiversity, cant live here
39
Supratidal zone
Almost never covered by water, except for when high tide w storm surge
40
Tidal bore
Flood tide creates a wave of water that travels upriver Large tidal ranges Incoming tide moves into narrow opening
41
Zones of a coastline
1. Coast 2. Shore
42
Coast
Extends inland as far as coastal processes reach
43
Shore
Low tide and highest point storm waves reach
44
Parts of the shore
1. Backshore 2. Foreshore 3. Offshore/nearshore 4. Shoreline
45
Shoreline
Position changes; at water's edge
46
Backshore
Above high tide level
47
Foreshore
Exposed at low tide, covered at high tide
48
Nearshore
From low tide shoreline to breaking waves
49
Beach
Wave-worked sediment
50
Beach face
Wet sloping surface
51
Berm
Shore-parallel ridge, dry sediment, high tide mark, mobile
52
Shephard coastal classification
1. Primary coasts 2. Secondary coasts
53
Variables that effect the classification of coastlines?
Materials, processes, forms, developmental age, environment, human impact
54
Primary coasts
Formed by non-marine processes (such as volcanic activity) ; young, possible strong terrestial influence
55
Secondary coasts
Shaped by marine processes; erosional or depositional processes dominate
56
Shephard Coastal classification- primary
2. Land erosional coast 2. Subaerial depositional coast 3. Volcanic coasts 4. Fault/tectonic coasts 5. Glacial/ice coasts
57
Land erosional coast
Subaerial coast Post glacial sea level rise Drowned coast
58
Subaerial depositional coast
Deposition by rivers, glaciers, wind, landslides
59
Shephard coastal classification- secondary
1. Wave erosion coasts 2. Marine deposition coasts (beaches and barriers) 3. Coasts built by organisms (reefs)
60
Submergent coasts
Drowned coastal zones Coastal land is sinking relative to sea level (transgressive) Land subsidence or sea level rise
61
Emergent coasts
Wave-cut terraces and platforms are exposed Coastal land is rising relative to sea level (regressive)
62
Erosional coast
Dominant processes are those that remove coastal material EROSION>DEPOSITION **more material being removed than added
63
Depositional coast
Material accumulated EROSION

GEOL200 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions