Brainscape's Knowledge GenomeTM

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


See full index

GLGY Sed Strat > Carbonate Sediments and Carbonate Rocks > Flashcards

Carbonate Sediments and Carbonate Rocks Flashcards

1
Q

Difference between Siliciclastic and Terrigenous

A
  • Siliciclastic is dominated by silicic fragments
  • Terrigenous is made up of detrital material eroded under non-marine conditions from pre-existing rocks terranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Intraclast

vs

Lithoclast

A
  • Intraclast - intrabasinal origin
  • Lithoclast - Extrabasinal origin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Spar vs Micrite

A
  • Spar - can be calcite or aragonite. Coarser then micrite > 4 micrometers carbonate cement. Origing 1) preciptiation out of water as cemet. 2) recrystallization of micrite or othe carbonate grain
  • Micrite- Cryptocrystalline carbonate mud. Origin is polygenic <4micrometers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Allochems

A

Broken off parts of organisms. the most commun source of carbonate clasts in the marine environment is biological. Many marine invertebrates and certain very commun algae produce precipitated carbonate structures (shells, plates,etc..). Upon death of the organism, these grains (or Allochems) become part of the fabric of the carbonate rocks.

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

Orthochem

A

The term used in the Folk classification to describe the micrite matrix and sparry calcite (sparite) cement in limestones.

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

Allochem Wiki def.

A

Allochem is a term introduced by Folk[1] to describe the recognisable ‘grains’ in carbonate rocks. Any fragment from around ½mm upwards in size may be considered an allochem. Examples would include ooids, peloids, oncolites,pellets, fossil or pre-existing carbonate fragments.

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

How ooids are formed?

A

Ooids form in areas where marine currents (for exemple, tidal currents) keep grains in motion.

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

Hermatypic

A

Hermatypic corals are those corals in the order Scleractinia which build reefs by depositing hard calcareous material for their skeletons, forming the stony framework of the reef.

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

what type of relationship hermatypic corals have with yellow-brown algae?

A

Algae provide nutrition (O2, glucose, amino acids)

Corals provide living space and easte nutrients (which used by algae) CO2, NO-3, NH+4 …

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

What is the major importance of corals in the ecosystem?

A
  • It creates new environments, so sedimentary structures are going to be different as well.
  • It changes the destribution of light and energy of the environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which organisms play a important role on the biomineralization of calcium carbonate?

A

Foraminifera, Bryozons, Molluscs, Echinoderms, Corals, pteropods, coccolitophores

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

which 2 organisms are the most important on the biomineralization of calcium carbonate?

A

Foraminifera and Coccolithopores

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

Carbonates belong to a group of rocks formed by……… and/or………….reactions

A

…..precipitation….biochemical…

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

Carbonates belong to a group of rocks formed by precipitation. Which other rocks are also included in the cabonates group?

A
  • Evaporite (salt, gypsum, etc..)
  • Chert (ilica) which also precipitates
  • Carbonaceous rocks (coal)
  • Others (phosphorites, iron-rich rocks)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What controls the inorganic preciptation of calcite in water?

A

cpH controls calcite precipitation via the amount of CO2 disolved in water.

DEGASSING (Release of CO2)

  • Increase in temperature (high temperature)
  • Decrease in pressure (think of a coke open)
  • Agitation

Note: you want shallow, warm and agitated (waves) environment.

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

What type of environmet facilitates precipitation of Calcite?

A

A shallow, warm and agitated (waves) environment.

Coastal marine

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

The chance of calcite being just CaCO3 is very ………..

They can also be made with ………….. and……………

A

Low

Mg and Fe

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

……………is very important when talking about carbonates.

A

Biology

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

Calcite vs Aragonite structure

A

Calcite is rhomboheadral

Aragonite is orthorhombic

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

In termes of crystal structure and chemical composition, aragonite is a …………………… of calcite.

A

Polymorphic

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

what happens with calcite in an acidic environment?

A

It dissolves

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

Name it:

1- CaCO3

2- FeCO3

3- MgCO3

4- CaMg(CO3)2

A

1- calcite / aragonite

2-siderite

3-magnesite

4- dolomite

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

How can you minimize the presence of carbonic acid in a aqueous environment?

A

Degassing:

  • Increase temperature
  • Decrease pressure
  • Agitation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

……………….reactions are responsable for the majorite of carbonate precipitation in an equaeous environment

A

BIOGENIC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The majority of carbonates precipitation is ……………..

A

Biogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Organic carbonate deposition is dictated by whatever makes the…………. of those carbonate secreating organisms to ……………

A

Biology/ succeed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What kind/s of biogenic processes are responsable for most carbonates precipitation?

A
  • Direct precipitation
  • Removal of CO2 linked to photosynthesis
  • Bacterially mediated

Bacterially mediated (biologically induced/controlled and linked to physiological processes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The distribution of carbonate-secreating algae is governed by……(6- T,S,L.a,C.s,Sub,F.a)….

A
  • Temperature
  • salinity
  • light availability (depth)
  • Current strength
  • Substrate
  • Food availability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Carbonate precipitation: The key controls are factors that limit/enhance the distribution/growth of particular organisms.The controls are:

A
  • Temperature
  • Salinity
  • Light availability (depth)
  • Current strength
  • Substrate
  • Food availability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the major controls on calcite precipitation?

A
  • Inorganic reaction
  • Biogenic
  • Hermatypic corals(reef building)
  • Water depth (CCD)
  • Evolution and distribution of organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is our current mode of carbonate sedimentation in the oceans?

A

Arogonitic + High-Mg calcite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Hard CaCO3 skeletons are secreted by……………………corals, which live in ……………….. with yellow -brown …………

A

Hermatypic/ symbiosis/ algae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How the symbiotic relationship of corals and yellow-brown algae works?

A

The algae provides nutition and the corals provide living space and waste nutients (which are used by algae)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

The algae provides ………….. and the corals provide……………. and ………………….. (which are used by algae)

A

nutition/ living space/waste nutients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what are the major two impacts corals have in the environment?

A

They change/alter the distribution of light and energy in the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Corals create new…………………,so we can expect ………………..to be also different.

A

environments/ sedimentary structures or deposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

CCD

A

Calcite compensation depth (CCD) is the depth in the oceans below which the rate of supply of calcite (calcium carbonate) lags behind the rate of solvation, such that no calcite is preserved.

or Calcite dissolves at much higher rates than it can precipitates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

CCD: Dissolution of……………….(first) then ……………. increases with ………………….and ……………….

A

Aragonite/Calcite

Depth/temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Below CCD ,……………….starts dissolving, but not…………………

A

Carbonates/ silicates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

below CCD you can find …………….rich sediments.

A

Silica

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

During green house Earth, the CCD will be ………………..then todays compasation depth (4kms) . During icehouse Earth, the CCD will be ………….then today depth. If we freeze Earth, then the CCD will be…………… than todays depth.

A

Lower (increase temp - increase pH)/ Same (we are living in a icehouse earth)/ higher (Decrease temp is related to lower pH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

The greater the depth, the more. concentration of…………, the more………… acid, the lower the………………

A

CO2/ Carbonic acid/ pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Can you find calcareous organisms in the bottom of the ocean (greatre than 4kms)?

A

No, this is below the carbonate compensation zone. the calcite available would dissolve leaving just Silicious ooze (forms chert).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is responsable for the great majority of silicious ooze in the bootom of the oceans (abyssal or greater than 4km)?

A

Wind-blown dust. (remember the sahara blowing silicious particle in the oceans)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

……………ooze forms carbonate mudstone and ……………….ooze forms chert.

A

Calcareous/ siliceous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Coral reefs have ………structures.

A

3D

47
Q

What are the consequences of coral reefs to the newly modifyed environment which they have created?

A
  • Incease in temperature of protected waters
  • Decrease in energy (buffle currents)
  • increase in salinity (depending on water cycle in protected lagoons)
  • Increase in nutrients
  • Increase in biomass
48
Q

What type of oceans/seas do we form during the cenozoic period?

A

(present) Aragonitic seas

49
Q

Global variations in ree-building/sediment-producing organisms during the phanerozoic is partly a functions of the composition of the sea water, resulting in………seas, typified …………., and ………..sea typified by………………

these variations depend on …………….ratio

A

calcitic/calcite

aragonitic/aragonite

Mg/Ca

50
Q

Aragonite is ……………….stable than calcite and at temperature of around 380 and 470C, ……………….will turn into………….

A

Less/ aragonite/calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380–470 °C,[5] and vaterite is even less stable.

51
Q

Wit increase in……………available in oceans, calcite will shift to…………….

A

Mg/ aragonite

52
Q

During diagenisis, ……………….will shift to ……………..

A

aragonite/ calcite

53
Q

What happens in the water-ocean composition/ Mg/Ca ratio during green house earth?

A

levels of Mg decrease due to incorporation of Mg into the crust due to volcanism.

54
Q

What happens in the water-ocean composition/ Mg/Ca ratio during icehouse earth?

A

With decrease volcanic activity, Mg level rise in oceans due to weathering.

55
Q

Aragonite is more stable than calcite in the presence of?

A

Magnesium

56
Q

with the increase of …………….in the system, calcite shifts to aragonite

A

Magnesium

57
Q

what happens to Magnesium during rapid sea-floor spreading?

A

Mg2+ in water, replaces Ca2+ in basalts to form Mg-rich clays, which in turn, decreases Mg/Ca ratio in oceans

58
Q

During intense volcanic activity, oceans waters cicles through the crust (hight temperature basalt-seawater rxn) involve large-scale removal of……………..content in the oceans allowing…………..seas to exist. When sea-floor preading slows down, increase in Mg content due to………………..

A

Mg/ Calcitic/ weathering

59
Q

During greeanhouse climates, formation of LMC is favared over…………….

A

aragonite

60
Q

During greenhouse climates, formation of ……….. is favared over aragonite and reverse is true for icehouse climates.

A

LMC (low-Mg Calcite)

61
Q

During icehouse climates, formation of aragonite + HMC is favared over…………

A

LMC

62
Q

Calcitic seas were coincident with times of rapid …………………………….

A

sea-floor spreading

63
Q

In general, precipitation of aragonite in preference to calcite is favored by ………… Mg/Ca ratio because of the inhibiting effect of Mg on calcite precipitation

A

High

64
Q

Carbonate distribution is largelly controlled by:

  • Cl…..
  • Tec…
  • Oce…
A

Climate

Tectonics

Oceongraphy (Controls the overall chemistry in the ocean)

65
Q

Climate, Tectonics and Oceongraphy determine?

T/ S/ N/ T / S and T currents/ W…….activity

A

Temperature

Salinity

Nutitients distribution

Turbidity

Storm and tidal current intensity

Wave activity

66
Q

What environment favors the highest rates of organic produtivity?

A

Shallow, warm and tropical climates (around 30 degrees from the equator)

67
Q

What is an exanple of reforming corals?

A

Mostly light- dependent Hermatypic corals and calcareous geen algae.

68
Q

Mostly light-dependent ……………….corals and calcareous…………..algae.

Whw\ere temperature drops below 15C to 0C, carbonate producers tend to be …………………. (e.g., ………….foraminifera, calcareous red algae, bryozoa)

A

Hermatypic/ green

Light-independent / Bentic

69
Q

Vast majority of carbonates are formed in ………………….waters

A

warm.

it doen’t mean they don’t form in cold waters

70
Q

Where is life most abundant, at what zone?

A

Photic Zone!

71
Q

At what depth (m), carbonate prdutivity (carbonate factory) is at maximum?

A

10-20 meters is the light saturation zone. below that, until ~ 100-200m is the base of photic zone

72
Q

what are the 3 main components of carbonate sediments and limestones?

A

Grains, matrix and cement.

73
Q

Give an example of skeletal grains

A

carbonate-producing animals, plants and bacteria

74
Q

Give an example of non-skeletal grain

A

Peloids, coated grains, lithoclasts

75
Q

Variours forms of………………….is precipitaded during diagenesis, from very early to deep burial to exposure (eo-, meso-, and telogenesis)

A

Cement

76
Q

Calcite cement likes to form around………….

A

calcite but it also forms around any grain. different than silica.

77
Q

Diffrence between Brachiopos and bivalves?

!!!

A

In Bachiopods, each of the two valves displays bilateral symmetry and Bivalves have two symetrical valves.

78
Q

Gastropods are very commun in……………marine environments. is mm-to-cm-sized coiled shapes, mostly b………

A

Shallow/ Benthic

79
Q

Cephalopods: Chambered shells (e.g. Nautiloids, ammonides). Ammonides are considerate great ……………….

A

Index fossils

80
Q

Converging evolution

A

2 different organisms evolved very differently by solving the same problem

81
Q

3 types of molluscs

A

Bivalves: present in most aquatic environments (relatively simple, smoth shells)

Gastropods: very commun in shallow marine environments (mm- to cm-sized coiled shapes, mostly benthic)

Cephalopods: Chambered shells (e.g. Nautiloids, ammonites [great index fossil])

82
Q

Brachiopods: mostly benthic, means……………, shallow marine.

more decorated shells than molluscs

Composed of multiple layers of LMC (early forms are phosphatic)

A

Lives in the ocean floor

83
Q

Foraminifera: small (tens of microns to cm-scale), single-cell…………….or…………..organisms.

Shell composed of HMC or LMC.

Very diagnostic! Good…………and …….indicators.

A

Benthic or planktonic.

pH and salinity

84
Q

Echinoderms:

Includes …………. (sea urchins) and …………(sea lilies) with skeletons composed or microporous plates and discs of LMC crystals.

They are very diagnostic and good biomarkers

A

echinoids/ crinoids

85
Q

Corals: main components of modern reefs together w/ ……………….

Modern forms are aragonite but calcite in the past.

Why is it aragonite nowadays?

A

Calcareous algae

High concentrations o aragonite + High-Mg calcite in the oceans.

86
Q

Stromatoporoids: extinct, primarily calcitic (?)

Important…………………. of the past

Mounded, laminated and dentritic (branch-like) forms

They have porous where they used to live

Very diagnostic!

A

Reef-.builder

because they are extinct, they may have formed as aragonite but since aragonite shifts to calcite it becames a gray area.

87
Q

Diffence between Stromatoporoids and Stromatolites

!!!!

A

Stromatoporoids were animals and Stromatollites are bacteria.

88
Q

Bryozoa: (Not corals or sponges) Fan shaped, dendritic and encrusting colonies of ………………animals. They live in structures for…………and…………..

mm to 1/2 meter in size

composed of aragonite or LMC

Well-adapted to deep, ……………..(20-30 degrees from the equator), marine setting.

A

Calcareous/ shelter and protection

Temperate

89
Q

……………….are very good in mixing (CO2 and temperature) what is going on in the atmosphere and the ocean.

The temperature of the surfice get transfered to the water, which changes its energy. Takes a lot longer for this to effect deep waters.

A

Ocean currents

90
Q

Algae : (NOT an animal, NOT a plant)

Highly varied group of………………….capable of secreating…………..or……… around (even”within”) their body.

Marine, brackish and freshwater groups.

Calcified stems and branches of…………………., encrusting and delicately branching red……….are both BENTHIC.

Bits and pieces when compacted in the sediment record

Green and red algae are the same.

A

photosynthesizers/ calcite or aragonite

green algae/ algae

91
Q

Define Index fossils

!!!

A

Widely distributes

Narrow range in time

regarded as characteristic of a given geological formation

92
Q

Not all algae are calcareoues.

true/false

A

true

93
Q

Is sea-weed a plant?

A

No

94
Q

Algae: Coccolithophores- yellow-green algae.

Presently widespread (white cliffs of dover), marine…………composed of very small crystals (0.25-1 um) forming disk shaped coccoliths (2-20 um) which assemble into coccospheres (10-100 um).

Principal constituint of …………….

They are great ………..fossils

!!!

A

plankton

Chalk

Index

95
Q

Cyanobacterial structures and Grains

Stromatolites: are…………….and photosyntetic!!!

Filamentous, sticky, slimy surfaces of bacteria.

trap and stabilize fine-grained carbonate sediment, forming………………………

Grow into sheet-like, columnar and domal-structures

They live in very…………..waters and <than></than>

<p>They form O2 as a waste product of photosyntesis.</p>

</than>

A

Bacterial (bacterial “slime”)

Microbial mats!!!!

Saline/ photic zone

(“they used to dominate the planet”)

96
Q

Stramatolites Grow into sheet-like, columnar and domal-structures

As they died, due to sedimentation on top of them, they grow…………………….with sediment.

They live in very…………..environments, warm and…………………….waters <than></than>

<p>They form O2 as a waste product of photosyntesis.</p>

</than>

A

Interlayed

Saline/ shallow/ Photic (light saturation zone)

97
Q

STROMATOLITES:

They form connected fillaments. They are one of the……………..forms of life in the planet. One billion years before life appearded!

Responsable for life on the planet. Due to photosyntesis, they go rid of O2 as a waste produt.

A

Oldest

98
Q

Cyanobacterial structures and grains:

ONCOIS:

……………………….structures

Form irregular, ~concentric layerss around a nucleus to form mm-to-cm-scale grains (around 1 1/2 cm across)

A

Bacterially-mediated

99
Q

Non-skeletal grains:

ooids:

Spherical/ovoid carbonate grains composed of a nucleous surrounded by concentric, smooth layers of even thickness (type of coated grain)

Form in………./………..waters.

A

Saline/hypersaline

100
Q

What are the requirements to form ooids?

What environment can you expect to find them?

A
  • Bottom agitation (at least periodically) - gently agitated
  • Shallow waters
  • water supersaturated with respect to calcite or aragonite (implies warm temperatures (gets rid of CO2-increase pH)!!!)
  • Limited amount of grain degradation (gently agitated).

Tidal flat.

101
Q

Ooids are formed in very specific waters.

What evironment and conditions at which they are formed?

A

TIDAL FLAT

very shallow

warm

High pH

gently agitated - regurlaly (oscillating currents)

102
Q

Carbonates like……………….waters?

A

Alkaline

103
Q

We can facilitate formation of ooids by minimizing…………………and…………..pH of the water.

A

Carbonic acid/ increasing

104
Q

Non-skeletal grains: peloids (pellets of some sort)

Relativelly small (<200um), poligenetic grains composed of micro-or……………-crystaline carbonate.

May orginate as:

………..pallets. Desintegration of ………………algae

micritized grains via biochemical……………(acid environment) and bacterial growth. Reworking of lithic clasts of…………………

A

crypto

fecal

calcareous

dissolution

carbonate mud

105
Q

Non-skeletal grains: peloids (pellets of some sort)

What is polygenic grains?

A

Formed in a varied of different ways.

106
Q

Non-skeletal grains: peloids (pellets of some sort)

What is the main difference between peloids ad ooids?

A

Peloids have no internal structure and ooids have structured concentric layers

107
Q

what is micitazation?

It forms………………

A

Is the break down of carbonaceous clasts through Chemical , Physical and biological processes.

Carbonaceous mud.

108
Q

During micritization, grains are …………………away and boken down into…………………..

Grains loose their ………………..structure

A

dissolved/ micrite

internal

109
Q

Non-skeletal grains: Lithoclasts

Intraclas: lithified/ partialy lithified carbonate fragment eroded from a nearby aproximately conteporaneoussediment.

Extraclast: fragment of carbonate/ non-carbonate rock derived from erosion of a unit located outside the depositional basin in which it is found. They are considerate………………..

Carbonates don’t usually travel……………

They weather very ease.

A

very rare

too far

110
Q

Micrite:………………….calcite

Formed as:

Lithified, mechanically deposited lime mud, or fine grained calcite crystals and particles formed in-place.

………………….,<=4 um, forming lime mud, lime ooze (very tiny in low energy environments), lime mudstone…

A

Microcrystalline

Cryptocristalline = microcrystalline

111
Q

Micrite: microcrystalline calcite

Modes of formation:

Inorganic physico-chemical precipitation (rare?)

Precipitation linked to ……….or ………life processes (biological)

Disentregation of calcareous fossils and fine erosional debris from lithified…………………

A

algal or microbial

carbonates

112
Q

Micite:

Two major sources are…………..and…………….

A

Biological and Physical

113
Q

Oncoids: Layered structures formed by………………………..growth.

Clacium carbonate structures are deposite by encrusting …………………..

Oncolides: Composed of oncoids. They are good indicators of ……………………waters in ……………………zone, but also known in fresh water environments. They rarelly exceed 10 cm in diameter.

A

Cyanobacterial

Microbes (microbial micrite!!)

Warm waters

GLGY Sed Strat (4 decks)

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