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Depositional environments Flashcards

1
Q

Hvad er eksempler på kontinentelle depositionel enviroments

A

Gletsjer, aeolian

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2
Q

Hvad kaldes deposits direkte fra is

A

Till - hvis det ikke er sammenpresset
Tillite - hvis det er consolideret/lithithied

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3
Q

Hvilke typer gletsjere findes der

A

Poler, polytherman, temperate

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4
Q

Hvad er moræne

A

Till der er samlet i kanten af en gletsjer

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5
Q

Hvordan dannes et till sheet under floating ice sheet

A

Noget is smelter og sedimenter ryger fra ice sheet ned på bunden af havet

Dette kan også sker under flydende isbjerge kaldes dropstone

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6
Q

Hvad er en Loess

A

Fragmenter (clastic) primært på størrelse med silt
blæses sammen

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7
Q

Hvilke strukturer ses i aeolian miljø

A

Sand dune
Alluvial fans
Dry alluvial plain
ephemeral lake

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8
Q

Hvordan dannes mushroom rock

A

Vinden er stærkest et bestemt sted over jorden - her vil der ske meget erosion pga vinden

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9
Q

Hvilke bedforms ses i aeolian miljøer

A

Ripple 1-64 cm
Dune 10-640 m
Draa fiels 640 - < 2,5 km

Største bedforms i verden

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10
Q

Hvad ses i bedforms i aeolian miljøer

A

Større fragmenter i toppen af dunen - finere på bunden

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11
Q

Hvordan ser man forskel på aeolien og sub-aquarius dunes

A

I aeolian er der grain-flow tounges i bunden af dunen

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12
Q

Hvilke ting er karakteristiske for aeolian dunes

A

Well-sorted and well-rounded sand grains are mostly deposited by aeolian dunes (wind cannot move pebbles!).

Grain-flow tongues at the foot of aeolian dunes help to distinguished them from subaqueous bedforms.

Wind ripples oriented perpendicular to the dune cross lamina is also characteristic for aeolian dunes.

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13
Q

Hvordan adskiller en sø sig fra havet

A

Ingen tidevand
Stille vand

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14
Q

River deposits

A

Konglomarater

Sand and pebbles:
Deposited by flowing waters
within or in the vicinity of river
channels

Mud (mostly clay):
Deposited by stagnant water in
floodplain (sometimes also in
abandoned channels)

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15
Q

Hvornår dannes leeves

A

I floder på ydersiden dannes der en lille banke

Levees form when flood waters rapidly deposit sediment close to the bank and crevasse
splays are created when the levee is breached.

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16
Q

Hvad er den største morfologiske karakteristik ved braided river

A

Mid-cannel bars

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17
Q

Hvilken forskel ses vertikel i aflejring mellem braided og meandering floder

A

Braided har mindre lag af mudder på toppen
Større lag under med sand

Braided er aglamated

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18
Q

Hvad er calcreres

A

calcium-rich duricrust, a hardened layer in or on a soil

Ses i bunden af floder - mellem flod og grundvand

Tykke lag er calcretes indikerer well-developed soil profile

Tynde lag af calcretes kan grundvand løbe gennem

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19
Q

Hvilke fysiske ting kontrollerer en flod

A

Principal physical controls on river type:
- Sediment load
- Slope
- Seasonality of runoff
- Baseline

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20
Q

Hvad er en point bar og hvordan dannes den

A

Den inderste del af en sving i en meandering flod

Sedimenter aflejres i svinget

Modsat i svinget ligger et cutoff

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21
Q

Hvad er foreshore

A

Strand

Her ses sand
Mellem mean high water og mean low water

Alle sedimenter vil blive reworked af bølger

Sand her vil blive aflejret som wave ripple, cross-lamination og horizontal stratification

Mudder vil ligge i flaser beds aflejret i perioder med mindre bølge energi
- de bliver mere almindelige i lidt dybere vand

Wave ripples vil blive mindre almindelige jo tættere man kommer på fair weather wave base

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22
Q

Hvad er shore fase

A

Mellem mean low water og fair weather base

Her ses sand

Alle sedimenter vil blive reworked af bølger

Sand her vil blive aflejret som wave ripple, cross-lamination og horizontal stratification

Mudder vil ligge i flaser beds aflejret i perioder med mindre bølge energi
- de bliver mere almindelige i lidt dybere vand

Wave ripples vil blive mindre almindelige jo tættere man kommer på fair weather wave base

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23
Q

Hvad er offshore-transition

A

Mellem fair weather base og storm wave base

Her ses mudder og tynde lag af sand sten med HCS

Sand aflejres og reworks af storm

Proximal tempestites have erosive bases and are composed of coarse detritus,
whereas the distal parts of the bed are finer-grained laminated sands: hummocky and swaley cross-stratification occurs in the sandy parts of tempestites.

Mellem storme aflejres mudder.
Disse fine korn kommer fra floder og ender hele vejen nede i offshore-stransition

Storm deposits er derfor adskilt af mudderlag. Medmindre mudderet eroderes væk

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24
Q

Hvad er offshore

A

Under storm wave base

Her aflejres primært mudder. Ikke engang storme påvirker dette område - ekseptionelle storme kan måske aflejret noget sand her

Grå sedimenter - intet oxygen

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25
Q

Hvad ses ofte i carbonate shallow miljøer

A

Tropiske steder - varmt - henrys lov

Tropisk koral rev

Ooids

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26
Q

Hvad er Symbiotic photozoan organisms

A

Koraller lever i symbiose med photozoan- beskyttelse for ekstra energi/O

Shallow water tropical corals (and some
other organisms) live in symbiosis with
zooxanthellae, which are single-celled
protozoans (dinoflagellates)

Kold vandkoraller lever ikke i symbiose med zooxanthella.

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27
Q

Hvilke faktorer kontrollerer miljøet i lavvands carbonate

A

Lys
Hvilke organismer der producerer sedimanter alt efter dybde

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28
Q

Hvad ses ofte i mudder dominerede siciliclastisk hav

A

Bioturmation

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29
Q

Hvilke photozoan findes der

A

Grønne alger - Calcareous green algae

Røde alger - Calcareous red algae = Rhodolith

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30
Q

HvilkeSymbiotic photozoan organisms findes der

A

Orbitolina
Nummulitetter
Rudister

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31
Q

Hvad er Heterozoan organisms

A

Ingen symbiose
Kold vandskoraller
Bryozoans
Echinoderms
Brachiopods

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32
Q

Hvilke organismer producerer sediment, når der er lys

A

Koraller
Grønne alger

Rudister
Stromatoporider

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33
Q

Hvilke organismer producerer sediment, når der er lidt lys

A

Større foraminiferer
Røde alger

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34
Q

Hvilke organismer producerer sediment, når der ikke er lys

A

Bryozoer
Mollusker
Chrinoids
Sponges

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35
Q

Hvad kaldes de forskellige lyszoner

A

Høj til lav
Eutrophic
Mesotrophic
Oligotrophic

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36
Q

Hvad danner carbon i koldt vand

A

Heterotrophic

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37
Q

Hvad danner carbon i varmt vand

A

autotrophic

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38
Q

Hvad er de to ekstremer for carbonate platforms

A

Homoclinal - lige rampe

Rimmed shelf - rampe med en klump på

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39
Q

What are the 6 parameters required to fully
characterize the Seawater carbonate system?

A

Nutrience, Salinity, Temperature, Depth, Type of organisms, Sunlight

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40
Q

Hvilke slags deltaer findes der

A

Tide dominated - Tidal power
River dominated - mellem tide og river
Wave dominated - River power

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41
Q

Hvilke slags estuary findes der

A

Tide dominated - Tidal power
Wave dominated - Mellem tide og river
Lagoon - River power

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42
Q

Hvilke controls er der på deltaer

A

Climate

Tektonics

Eustatic sea level

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43
Q

Delta deposition - river dominated

A

Delta Top
- channel og overbank
- her kan være meget vegetation
- sediment aflejringer ligner fluvial

channel udmunder i bird’s foot
i bays her er fine sedimenter

Delta Front

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44
Q

Hvad karakteriserer river dominated delta

A

Der er noget der stopper bølgerne fra når kystlinjen

Low-energy, interdistributary bays are a characteristic of river-dominated deltas.

Interdistributary = omsluttet af en bay - en lille lomme

Bird’s foot pattern

Der er en lobe i bunden af floden - disse bliver ikke reworked af bølger
Denne flod kan skifte position når floden ændrer kanal

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45
Q

Hvad karakteriserer wave dominated delta

A

A wave-dominated delta formed where wave activity reworks the sediment brought
to the delta front to form coastal sand bars and extensive mouth-bar deposits

Der sker ikke meget prodegation fordi bølgerne hurtigt piller ved sedimenter i udmundingen
prodagation sker fordi bølgerne ikke kan flytte sedimenterne væk

Sedimenter kan migrere lateralt pga vind

Der dannes sandbunker, der er parallele med kysten

Bølger er gode til at sortere grans

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46
Q

Hvilken forskel ses mellem wave og river dominated deltaes

A

River = mindre kontinuerlig mouth bars, mere channel og overbank.
Delta lobes

Deposits mellem de to ligner hinanden

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47
Q

Hvad karakteriserer tidal dominated delta

A

Der dannes aflange aflejringer væk fra kysten. Tidal sand bars

Intertidal zone

Tidevandsaflejringer
Perioder udenbevægelse - mudder

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48
Q

Hvordan kender man forskel på tidal dominated delta og estuary

A

Delta har karakteristisk “coarsening-up”
- Sedimenterne bliver grovere længere væk fra havet

The main
distinguishing feature is that a delta is always a
progradational feature, whereas an estuary commonly
forms as part of a retrogradational, or transgressive,
succession

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49
Q

Hvad er en esturary

A

Del af havet der modtager sedimenter fra både floder og hav
Bliver påvirket af flod, tidevand og bølger

Transgressive

Er tredelt

Hav del - sedimenter går ind ad - bølger
Mellem del - ikke meget energi - tidevand
Flod del - sedimenter går mod hav

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50
Q

Hvad er en lagune

A

shallow body of water partly or completely
separated from a larger body of water by a barrier, which can be a bioconstructed reef, a clastic beach barrier or hard rocks ridge.

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51
Q

Hvilke to slags siliciclastiske strande (littoral) findes der

A

Dissipative
. bred surf zone
- typisk sand

Refrective
- stejl
- lille surfzone
- sand og grus

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52
Q

What is a beach berm?

A

Berm er et stykke af stranden der adskiller foreshore fra backshore

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53
Q

What characterizes lagoonal facies?

A

A lagoonal succession is typically
mudstone, often organic-rich, with thin,
wave-rippled sand beds

Ligner en sø
- marine forssiler kan fortælle der er en lagune

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54
Q

Hvilke slags sedimentære processer sker på det dybe hav

A

Mass-flow processes.

debris flows, density
flows and turbidity
currents

Bouma sequence

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55
Q

Hvordan starter massflow processes

A

Trigger - jordskælv, seismisk aktivitet

For meget sediment samlet på shelfen

Store strom bølger

Meget sediment fra floder

A fall in sea level exposes shelf
sediments to erosion, more storm effects
and sediment instability that result in
increased frequency of turbidity currents.

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56
Q

Hvad er et hyperpycnal flow

A

Turbidity flow der fortsætter - sker pga forhøjet sedimenter fra flod

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57
Q

Hvad er contourites

A

Sediment aflejringer på bunden af havet
Dannes af vanden der strømmer på bunden
Parallele med konturer på havbunden

Kontinuerlige i stedet for single event som tubidite

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58
Q

Hvad er pelagic sediment

A

pelagite

Fine sedimenter der samles på bunden fra det åbne hav

Der er tre typer siliceous oozes, calcareous oozes, and red clays.

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59
Q

Hvad er ooze

A

pelagic sediment

> 30% mikrospiske carbon er si rig planktoniske organismer

Resten er ler

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60
Q

Hvilke fire faktorer kontrolerrer pelagic sedimenters komposition

A
  • Distance from major landmasses (affects dilution from terrigenous and other land-derived sediments)
  • Water depth (affects preservation of both siliceous- and calcareous biogenic particles that settle to the ocean bottom)
  • Oceanic fertility (controls the amount of biogenic particles produced in surface waters)
  • Bottom currents (affects preservation of pelagic sediments due to erosion, reworking and re-deposition)
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61
Q

Hvad er CCD

A

Carbonate compensation debth

Grænsen hvor carbonater opløses

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62
Q

Hyper concentrated flow

A

Density flow

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63
Q

turbidity flow

A

Creates bouma sequence. The most common clastic deposit

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64
Q

Why are bouma sequences rarely complete?

A

Because of nonuniform grain size distribution and flow transformations

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65
Q

Hvad er forskellen mellem et tubidity flow og en bourma sequence

A

Bourma er kun en retning

Turbidite er interference

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66
Q

Deep clastic sea lithologies

A

Mud, sand and gravel

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67
Q

Deep clastic sea mineralogy

A

Arenites - may be lithic or arkosic (feldspar rich)

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68
Q

Deep clastic sea texture

A

Variable. Some turbidites. Poorly sorted.

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69
Q

Deep clastic sea Bed geometry

A

Mainly thin sheet beds

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70
Q

Deep clastic sea sedimentary structures

A

Graded turbidite beds with some horizontal and ripple lamination

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71
Q

Deep clastic sea paleocurrents

A

Bottom structures and ripple lamination in turbidites show flow direction.
Deep clastic sea paleocurrents

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72
Q

Examples of pelagic life

A

Diatom, radiolaria, forarminifera

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73
Q

“layer cake” stratigraphy

A

What important stratigraphy feature from the pelagic open ocean is this?

Horizontal layeringer with a small tilt

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74
Q

Hvad er CCD

A

carbonate compensation depth (CCD)

the ocean depth below which the seawater is sufficiently undersaturated with calcium carbonate that calcium carbonate shells and skeletons dissolve

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75
Q

What chemical compound in the ocean reachts with CaCO3 and dissolves the shells?

A

CO2

76
Q

How can calcite be deposited, when there is a CCD?

A

The topography of the ocean bottom may result in calcite being deposited, as some areas lie above the CCD

77
Q

What does the depth of the CCD tell us about the ocean?

A

How acidic it is. The closer the CCD is to the ocean water surface, the more acidic is the water. Likewise is the CO2 concentration also important.

78
Q

What can still be found below CCD?

A

silliceous ooze and clay

79
Q

What are the main depositioal environments?

A

Continental, transitional, marine, volcanic, lacustrine, river.

80
Q

Amphidromic point

A

A point which the tidal wave rotates around. At this point, there is no change in water level during the tidal cycle, and there are no tides.

81
Q

Density flow

A

Mixtures of detritus and fluid that move under gravity, are known as density flows / currents (debris flow).

82
Q

Turbidity currents

A

gravity-driven turbid mixtures of sediment suspended in water. They are less dense mixtures than debris flows and has a high Reynolds number. Often turbulent flow. The name comes from being mixtures of opaque mixtures of sediment and water (turbid), and not from turbulent flow.

83
Q

Why are pelagic sediments so boring?

A

The pelagic sediments depend on nutrients of the water, and the deposits reflect topography. For instance: Radiolarian ooze is primarily found at the equator and the west coast of continents, because the water is rich in nutrients.
This means, that types of pelagic sediments are quite uniform, but the type of sediment depend on the environment.
They are also boring because they are made of only CaCO3

84
Q

How are carbonate ramps divided?

A

Offshore, deep subtidal and shallow subtidal

85
Q

Depositional environment of offshore and deep subtidal

A

Thin packstone storm beds in lime mudstone. May be graded or contain HCS and sole marks.

86
Q

Depositional environment of Shallow subtidal (above FWWB)

A

Large sandbars. Large subaqueous dune. Cross bedding made of ooids and skeletal fragtments. May also have wave ripples and parallel beach laminations

87
Q

Teepee structures

A

Dessiccation (= drying out) cracks are formed by wetting, drying and thermal contraction during a tidal cycle. VERY COMMON for peritidal deposition - often seen as polygonal desiccation cracks (like mud cracks). · Continued wetting and drying of cessiccation cracks can deform the lamination upwards, which creates the teepee structure.

88
Q

Carbonate platform

A

Low gradient to flat, shallow, broad top with very steep slope. May have platform-edge barrier (reef or shoals)

89
Q

(un)Rimmed platform

A

When there is a barrier present = rimmed

Platforms without a barrier = unrimmed

90
Q

Energy distribution on a rimmed platform

A

we find the energy maximum at the reef boundary (the platform edge). The interior has low energy.

91
Q

Energy distribution on an unrimmed platform

A

have an energy maximum at the margins (platform edge) because of the wave focusing as the water abruptly shallows at the edge of the platform. As the water slows across the platform (frictional energy loss), will it lose energy from friction.

92
Q

Berm formation

A

Dissipative coast and reflective coast

93
Q

Coastal plain

A

Land area that lies adjacent to the max tide level

94
Q

strand plain

A

Sandy coastline where an extensive area of beach deposits lies directly adjacent to the coastal plain.

95
Q

Lagoonal succesion

A

Typically, mudstone, often organic rich, with wave-rippled sand beds. The fossil assemblage may indicate a marine influence. A restricted fauna may provide evidence of brackish or hypersaline water.

96
Q

Littoral Clastic coast bed geometry

A

Elongate lenses

97
Q

Littoral Clastic coast Sedimentary structures

A

Low angle stratification and wave reworking

98
Q

Littoral Clastic coast Paleocurrents

A

Mainly wave formed structures

99
Q

Shoreface stratigraphy

A

Wave ripple, low angle ripples, bioturbation, wave ripple cross lamination and horizontal stratification. Flaser beds.

100
Q

Sedimentary structures of the offshore transition zone

A

Tempestites, finer-grained laminated sands, HCS, SCS. Alternation layers of sand and mud.

101
Q

Characteristics of tide-dominated successions

A

Large sand ridges with moderately well sorted, medium grained sand. Deposits may include clay laminae deposited during slack phases. Likely cross bedded and cross laminated sandstone.

102
Q

Characteristics of tide-dominated successions

A

Large sand ridges with moderately well sorted, medium grained sand. Deposits may include clay laminae deposited during slack phases. Likely cross bedded and cross laminated sandstone.

103
Q

Why are reefs located the way they are?

A

Warm water contains less CO2, which means it contains more carbonate iron.

104
Q

euphotic zone

A

Upper layer of a body of water through which sunlight can penetrate and support photosynthesis. Supports life of corals, green algae and rudists

105
Q

oligophotic zone

A

15 - 100 m water depth. A medium amount of sunlight penetrates, which supports the life of red algae and larger forarminifera.

106
Q

aphotic zone

A

The deeper layer of ocean water that lacks sufficient sunlight for photosynthesis. Only supports life for heterozoan organisms. Bryozoans, mollusks, spongies.

107
Q

What other than sunlight controls the life forms in the ocean?

A

Salinity and nutrience level

108
Q

Hypertrophic

A

A lot of nutrience

109
Q

Levels of nutrience

A

Oligitrophic, Mesotrophic, Eutrophic, Hypertrophic.

110
Q

M factor

A

Mud-mound + Micrite: Microbes and mud

111
Q

C factor

A

Cool-water + controlled precipitates: Heterozoans

112
Q

T factor

A

Tropical + Topmost water: Mostly photozoan (autotrophic + Needs life (they need food)

113
Q

Micritization

A

Endolithic (live inside the rock) microbes (algae, fungi, bacteria) bore into allochems and their tubes are later filled by micrite.

114
Q

Micrite formation

A

Partly form by inorganic precipitation in the surface ocean (whitings)

115
Q

Movement of temperate glaciers

A

Basal sliding and plastic deformation

116
Q

Movement of cold glaciers

A

Plastic deformation

117
Q

lateral moraine

A

A ridge of till along the sides of a valley glacier composed primarily of debris that fell to the glacier from the valley walls.

118
Q

medial moraine

A

deposit of sediment formed when the lateral moraines of two glaciers meet

119
Q

recessional moraine

A

Marks the pauses in the retreat of a glacier

120
Q

terminal moraine (end moraine)

A

a type of moraine that forms at the snout (edge) of a glacier, marking its maximum advance

121
Q

Creation of snowball earth

A

CO2 and water combines and weathers silicate rocks. Less CO2 in the atmosphere makes it colder. Ice is spreading. Large albedo effect. The earth freezes. Volcanoes erupts and emits CO2, which builds up. Ice melts, because of the greenhouse effect from CO2.

122
Q

Loess

A

Aflejringer fra gletsjere

A wind-formed deposit made of fine particles of clay and silt

123
Q

Windkanter

A

Dannes af aeolian - vind sliber kanter

124
Q

Where is the maximum erosional potential? - Aeolian

A

About 1 meter above ground (max wind speed + max amount grains).

125
Q

What happens during a storm in aeolian environments?

A

Large amounts of dust is blown away. Can be blown from Sahara to Bahamas for instance –> The reason for clay minerals. Also provides nutrience. Dust can be carried with the wind

126
Q

What is desert varnish?

A

A dark, rusty-brown coating of iron oxide and magnesium oxide that accumulates on the surface of the rock, as very fine sand and particles are moved by the wind.

127
Q

Define Star Dunes

A

Isolated hills of sand that exhibit a complex form, as wind has blown from all directions

128
Q

Why are most dunes asymmetrical

A

Because they follow the prevailling winds, making the stoss side gentle in slope, and the lee side more steep (avalanching).

129
Q

What is seen in aeolian dunes, but NEVER in marine?

A

Avalancing on the lee side of dunes

130
Q

Define Barchan Dunes

A

Dunes shaped like crescents with the tips pointing downwind from where there is little sand and a flat surface. The crescent forms when the wind is stable and fixed.

131
Q

Define Linear dunes

A

have their crests parallel to the wind direction. These
dunes frequently have a slipface on each side and are probably formed from winds that come from two close directions, say south and southwest. The dunes are aligned between the two directions. Because of the two wind directions, they often have two slipfaces. These dunes are frequently found in groups of parallel dunes, which can extend for hundreds of kilometers.

132
Q

What is NOT found in aeolian environments?

A

Fossils

133
Q

What is characteristic about about aeolian dunes?

A

The grainflow tongues out at the bottom of the dune, which subaqueous bedforms doesn’t.
You will also often find wind ripples orientated perpendicular to dune cross lamina.

134
Q

What does lacustrine and ocean environments have in common?

A

Bedform (except tides)

135
Q

Where do deltas form?

A

as a stream enters an ocean

136
Q

How do seas and lakes differ?

A

Fauna and flora. Water chemistry. Certain physical processes of temperature and density stratification.

137
Q

What controls the water level in a lake? And the water chemistry!

A

The balance between inflow, outflow, and evaporation.

138
Q

Lake water stratification

A

Contrast in temperature, density and chemistry in the upper and lower part of the water body

139
Q

Thermal stratification of (fresh) lakes

A

Oxic upper layer, and a colder, anoxic lower layer.

140
Q

Hypolimnion

A

deeper water; cold, dense; low dissolved oxygen in a lake

141
Q

Epilimnion

A

An upper layer of warm water with high levels of dissolved oxygen in a lake

142
Q

Controls for sedimentation in a lake

A

Density stratification above and below the thermocline

143
Q

Saline lakes cause

A

Salt lake; commonly caused by interior stream drainage in an arid environment

144
Q

What does it mean, that a river always try to reach a equilibrium?

A

A river will mostly erode the same during its run. On slopes will the erosion be controlled by the energy of the slope, and on flat ground is it the energy from the amount of water in the river.

145
Q

What happens to the equilibrium, when you remove sediment from a river?

A

the energy of the river will be larger, and it will start to erode more, and thereby reach a new equllibrium.

146
Q

Anabranching channel

A

multiple large channels are present across a vast floodplain

147
Q

Braided river

A

Form when many small river channels interconnect between areas of abundant sediment deposition. Common where glaciers flow into valleys and release meltwater and abundant sediment.

148
Q

Levees

A

Barriers composed of river sediments made on either side of a river due to flooding.

149
Q

How does the water flow in a meandering river?

A

When water is flowing alongside a curve (and the Coriolis force deflect the water molecules), the water on the outer bend of the water, will flow faster than the inner bend of the curve.

150
Q

Crevasse splays

A

are created when the levee is breached. –> Erosion makes a “hole” which makes a lot of sand flow out

151
Q

River bars

A

An elevated region of sediment that has been deposited by the flow. Complex features, composed of stacked bedforms. The dimension of the bars is related to the channel width.

152
Q

Amalgamated

A

Connected bodies of sand makes large reservoirs, but water may escape. There is also higher risk of pollution of the water

153
Q

Non-amalgamated

A

May be good reservoirs, as sand-bodies are not connected. Sealing rock may be present.

154
Q

Concretion

A

Hard, rounded mass that develops when a considerable amount of cementing material precipitates locally in a rock, often around an organic nucleus.
Often CaCO3

155
Q

Concretion

A

Hard, rounded mass that develops when a considerable amount of cementing material precipitates locally in a rock, often around an organic nucleus.
Often CaCO3

156
Q

The Neritic zone

A

In which deposits are waves and tides a great identification of a marine environment

From the coast and down to a depth of 200 meter (shallow water)

157
Q

The Bathyal zone

A

The Bathyal zone

158
Q

The Abyssal zone

A

What zone lies between 4000 m and 5000 meter water depth?

159
Q

Mention the different “faces” of a marine environment

A

Offshore, Offshore-transition, shoreface, foreshore

160
Q

Where lies storm wave base?

A

Between offshore and offshore-transition

161
Q

Where lies fair weather wave base

A

Between offshore-transition zone and shoreface.

162
Q

Where do we find mean high water and mean low water

A

Beyond and before the foreshore

163
Q

Which parameters are used for describing transitional environments?

A

1) Transgression / regression
2) Is there a river nearby?
3) Main transport agent

164
Q

Transitional environemnt without a river?

A

Tidal flat, strandplan, lagoon

165
Q

Transitional environment with a river

A

Delta or Estuary

166
Q

Delta formation

A

Deltas are formed when rivers propagate to the sea and deliver sediments.

167
Q

What does a delta integrate?

A

Sea leve change, mountain building, waves, tides and climate.

168
Q

What does the climate control in deltas?

A

Discharge

169
Q

What do tectonics control in deltas?

A

Relief, slope and subsidence

170
Q

What do eustatic sea level changes control in deltas?

A

Accommodation, waves and tides

171
Q

What do discharge, relief and slope control in deltas?

A

Grain size

172
Q

What do subsidence and accomodation control in deltas?

A

Depth

173
Q

What do waves and tides control in deltas

A

Reworking of sediments

174
Q

What mouth bar does fine-grained deltas have?

A

Small mouth bar

175
Q

What mouth bar does Coarse-grained deltas have?

A

Larger mouth bars

176
Q

Delta deposits that will move with time.

A

Lobes

When a delta channel avulses (adskilles), will the deposits (lobes) build out the new location of the delta mouth.

177
Q

Sedimentary structures of tide deltas

A

River progrates into the ocean.
Herringbone cross stratification
Mud drapes
Neb-spring cycles
Flaser, wavy and lenticular lamination.
Interferece and ladder ripples.

177
Q

Sedimentary structures of tide deltas

A

River progrates into the ocean.
Herringbone cross stratification
Mud drapes
Neb-spring cycles
Flaser, wavy and lenticular lamination.
Interferece and ladder ripples.

178
Q

Sedimentary structures of wave deltas

A

Symmetrical ripple marks and HCS

179
Q

Progradation

A

Seaward extension of the shoreline through deposition of sediment

180
Q

Regression

A

Seaward extension of the shoreline through lowering of sealevel

181
Q

auses for regression / progradation

A

Entering glacial period (less sea water), tectonic activity uplifts land, high sedimentation rate

182
Q

transgression

A

Higher sea level (Shoreline moves landward)

183
Q

Retrogradation

A

Subsidence of land (Shoreline moves landward)

184
Q

Causes for transgression / retrogradation

A

Leaving glacial period (More sea water), tectonic activity lowers the land (from weight on top), low sedimentation rate, river that delivers sediments has been cut off (for example a meandering river)

SoS (6 decks)

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