Brainscape's Knowledge GenomeTM

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


See full index

Geology > Sedimentary Rocks and Processes (A2) > Flashcards

Sedimentary Rocks and Processes (A2) Flashcards

1
Q

Define Weathering

A

The in situ breakdown or decomposition of rocks and minerals through chemical, biological and physical processes

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

Define Erosion

A

The weathering down of rocks by the mechanical action of transported debris

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

What are two types of physical weathering?

A

Freeze-thaw, Insolation

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

What are five types of chemical weathering?

A

Carbonation, Oxidation, Hydration, Hydrolysis, Solution

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

What is a type of biological weathering?

A

Root growth

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

Define Arenite

A

A sandstone with less than 15% matric

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

Define Wacke

A

A sandstone with between 15 and 75% matrix

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

Define Lithic Fragment

A

A rock fragment

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

Define Facies

A

An area with a distinctive sediment type

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

What are the four facies in a desert environment?

A

Scree, Alluvial fan, Aeolian sandstone, Playa lake

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

Define Mesa

A

A portion of a plateau separated from the main plateau

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

Define Butte

A

An isolated tower, remnant of a plateau

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

Define Wadi

A

Dry riverbed eroded by flash flooding

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

Define Sabkha

A

Evaporate deposits left behind after floodwater in coastal areas/lagoons is evaporated

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

What is the trend in grain size in an alluvial fan?

A

Courser closer to the source and finer further away

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

What are two factors controlling grain size in an alluvial fan?

A

The amount of water and The velocity of the water

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

What is the mode of transportation of the grains in an alluvial fan?

A

Carried as a bed load in water

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

What is the reason for deposition of the grains in an alluvial fan?

A

Grains are deposited when the water loses velocity

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

What is the mode of transportation of the grains in sand dunes?

A

Wind

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

What is a sedimentary feature commonly found in sand dunes?

A

Large scale cross bedding

21
Q

What is the texture of the grains in a sand dune?

A

Sand sized particles, Well rounded, Well sorted

22
Q

What is a playa lake?

A

Site of a former or occasional lake

23
Q

What are the four main deposits found in a playa lake?

A

Calcite, Gypsum, Halite, Magnesium

24
Q

What is the reason for the order of the deposits of a playa lake?

A

Differing evaporation rates of the deposits mean some come out of solution before others e.g. Magnesium is most soluble so is deposited last

25
Q

How are ripples formed?

A

High velocity water picks up sand grains on the stoss side of the ripple and a drop in velocity on the lee side causes the grain to be deposited

26
Q

What are two fossils found in a fluvial environment?

A

Roots from plants will be preserved on the flood plain, Fish in rivers

27
Q

What are three bedforms in a fluvial environment?

A

Floodplain, Point bar, Channel

28
Q

Define Delta

A

Formed when a current of water carries sediment into deeper, relatively still water, causing sediment to be deposited

29
Q

What are five features of a delta top?

A

Channels, Point bar sands, Levees, Distributaries, Fan shaped lobes

30
Q

Define Flocculation

A

Saltwater is an ionic solution which causes clumping and cohesion of clay particles, increasing size and mass allowing it to settle

31
Q

What is Walther’s Law?

A

Facies that occur next to each other are recorded vertically in sequence

32
Q

Define Prograding Delta

A

Building out into the sea because sediment brought in is greater than subsidence on the delta

33
Q

What is recorded in the deposits in a prograding delta?

A

Marine transgression

34
Q

Define Retrograding Delta

A

Reducing in size because sediment brought in is less than subsidence on the delta

35
Q

What is recorded in the deposits in a retrograding delta?

A

Marine Transgression

36
Q

Define Isostatic

A

Local change in sea level related to the loading of the lithosphere by sediment deposited on the delta

37
Q

Define Eustatic

A

Global changes in sea level linked to periods of glacial/interglacial as well as an increase in mid-ocean ridge activity

38
Q

Define Turbidite

A

A deposit from the turbidity current

39
Q

Define Turbidity Current

A

An underwater avalanche

40
Q

Define Bouma Sequence

A

Idealised sequence of one turbidity event

41
Q

What are two reasons a bouma sequence might be incomplete?

A

Distance from source, Top layers could be eroded

42
Q

What are five conditions required for limestone formation?

A

Marine water, Shallow water depth, Warm water temperature, Clear water, Well oxygenated and nutrient rich

43
Q

Define Fringing Reef

A

Formed around the edge of a small landmass/volcanic island, attached to the land

44
Q

Define Barrier Reef

A

Reef grows at the same rate as the sea levels rise

45
Q

Define Atoll

A

Eventually, the island is covered by water, creating an atoll and lagoon

46
Q

Where does chalk form?

A

In shallow water in the photic zone

47
Q

What are the three steps in chalk formation?

A

(1) Coccolithophore dies (2) Coccolithophore falls apart, taking a long time to settle to the ocean floor (3) Form usually on continental shelf due to Carbonate Compensation Depth (CCD)

48
Q

Define Carbonate Compensation Depth (CCD)

A

The depth of water carbonate shells will dissolve back into the water

49
Q

What are the two stages of diagenesis?

A

Compaction and cementation

Geology (16 decks)

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