Ear212 - 100 Short Questions Part 2 - Sedimentology

Front 1

Cemented beach sands are common in which diagenetic environment?

Back 1

Marine Vadose (Intratidal - Supratidal)

Front 2

Cements in modern beach rocks typically consist of which carbonate mineral?

Back 2

Aragonite

Front 3

The formation of cemented beach sands typically occurs how far below the surface

Back 3

10's of cm

Front 4

Microbial micritisation is common in which diagenetic environment?

Back 4

Marine Phreatic (Shallow Subtidal Marine)

Front 5

Formation of grapestones and aggregates is common in which diagenetic environment?

Back 5

Marine Phreatic (Shallow Subtidal Marine)

Front 6

Carbonate dissolution commonly occurs in which diagenetic environment?

Back 6

Meteroic Vadose

Front 7

What is the defining feature of isopachous cements?

Back 7

It forms an equal rim of cement around a grain

Front 8

As rainwater is undersaturated with respect to CaCO3, this leads to which process?

Back 8

Dissolution

Front 9

As water moves downwards through the meteoric vadose zone via diffuse or conduitflow it become saturated in CaCO3 so that cementation occurs. These cements aretypically what type of carbonate?

Back 9

Low-Mg Calcite

Front 10

Name a carbonate mineral that is highly susceptible to dissolution?

Back 10

Aragonite

Front 11

In arid settings what is the typical rate of alteration?

Back 11

Slow.

Front 12

Ferroan cements contains elevated concentrations of which element?

Back 12

Iron

Front 13

Name an environment in which cementation takes place where CaCO3 enriched watersresult from evaporation?

Back 13

Cave systems.

Desert Wadis.

Front 14

With respect to carbonate diagenesis principle cements types include aragonite; highMgcalcite; low-Mg calcite and dolomite. Name a less common cement type associatedwith carbonate diagenesis?

Back 14

Ankerite.

Siderite.

Quartz.

Front 15

Slow and continuous cementation processes in the meteoric phreatic diageneticenvironment lead to what type of cement morphologies?

Back 15

Large blocky spars

Front 16

Increasing ambient Mg/Ca supply combined with increasing carbonate ion supplytypically leads to which cement morphology?

Back 16

Acicular

Front 17

In which latitudes is seawater supersaturated with respect to CaCO3 today?

Back 17

The Tropical Latitudes (~25o N/S)

Front 18

What is the surname of the geologist who devised the Facies code system for fluvialdeposits?

Back 18

Miall

Front 19

What does a sedimentary facies allow the interpretation of?

Back 19

Sedimentary processes

Front 20

What does a facies association allow the interpretation of?

Back 20

The environment of deposition

Front 21

Name a sedimentary process that is typical of alluvial fan environments?

Back 21

Sheetflood.

Debris flow.

Front 22

In stratigraphy, what is the name of the law that describes the arrangement ofsedimentary facies in space and time?

Back 22

Walther's Law

Front 23

Name an environmental controlling factor that can result in the development of acoarsening or fining upwards facies sequence?

Back 23

Climate

Front 24

An alluvial fan with a low surface slope and a large catchment area will be dominated bywhat kind of sedimentary process?

Back 24

Sheetflood

Front 25

An alluvial fan with a steep surface slope and a small catchment area will be dominatedby what kind of sedimentary process?

Back 25

debris flow

Front 26

Name a facies model for an alluvial fan setting?

Back 26

Miall, 1977.

Scott, 1967.

Front 27

Meandering river channels can often undergo avulsion. Name a cut off process thatresults in avulsion?

Back 27

Neck Cut-off.

Shute cut-off.

Front 28

Palaeosols in floodplain deposits that show grey mottling indicate what kind of climaticsetting?

Back 28

Humid climate

Front 29

What is a lake setting characterised by evaportic sediments called?

Back 29

Playa lake

Front 30

The development of evaporitic minerals on a lake floor will result in the formation ofwhat kind of surface cracks?

Back 30

Desiccation cracks

Front 31

What kind of basin fill geometry is formed within a symmetrical rift basin?

Back 31

Graben

Front 32

What kind of sedimentary environment characterises the footwall setting of a terrestrialrift basin?

Back 32

Alluvial fan

Front 33

The axis of an externally drained rift basin is dominated by what kind of sedimentaryenvironment?

Back 33

Axial drainage channel

Front 34

What is the collective name of the sedimentary facies that develops within theunderfilled stage of foreland basin development?

Back 34

Flysch sediments

Front 35

What is the collective name of the sedimentary facies that develops within the overfilledstage of foreland basin development?

Back 35

Mollasse sediments

Front 36

What are the main deltaic-sub environments?

Back 36

Pro-delta.
Delta front.

Delta Plain.

Front 37

What are the main sub-environments in a delta plain?

Back 37

Distributary channels.

Interdistributary Bays

Front 38

What are names of the two processes which deliver sediment from distributary channelsto inter-distributary areas?

Back 38

Crevassing.

Overbank-flooding.

Front 39

What kind of facies successions typify minor mouth bar progradation?

Back 39

Coarsening up cycles, found in delta plain successions

Front 40

What kind of dense flows deliver coarse sediment to the distal delta front and prodelta?

Back 40

Hyperpycnal

Front 41

Hypopycnal conditions are occur when?

Back 41

Low density flowing water, meets higher density standing water

Front 42

What is the key difference between failure-induced turbidites and hyperpycnalturbidites on delta fronts?

Back 42

Hyperpycnites differ from other turbidites because of their well-developed inversely graded facies andintrasequence erosional contacts - Mulder, et al 2003.

Front 43

Normal regression in deltas generates what kind of facies succession?

Back 43

Coarsening up, shallowing up succession

Front 44

What sedimentary features are typical of delta front successions which are not found inoffshore shelf deposits?

Back 44

Heterolithic clinoforms

Front 45

Which type of sedimentary structure is unique to the offshore transition zone?

Back 45

Hummocky Cross Stratification

Front 46

Palaeocurrent distributions from trough cross bedding deposited in the upper shorefaceare likely to show what kind of distribution?

Back 46

Parallel to the palaeo-shoreline

Front 47

The thicknest successions in nearshore facies are likely to be deposited during what kindof genetic behaviour?

Back 47

Progradation associated with Normal Regression

Front 48

What flow regime does parting lineation develop in?

Back 48

Upper Flow regime

Front 49

What kind of genetic behaviour occurs when sediment supply rate in the nearshore zoneis greater than the rate of relative sea-level rise?

Back 49

Normal regression

Front 50

How can erosion surfaces generated by regression and transgression bedifferentiated in nearshore successions?