Brainscape's Knowledge GenomeTM

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


See full index

CIVIL 220 > Introduction to Sedimentary Rocks > Flashcards

Introduction to Sedimentary Rocks Flashcards

1
Q

Sediment

A

material weathered from pre-existing rocks

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

Sedimentary rocks

A

rocks made up of sediments

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

Important factors characterising depositional environments

A
  • type of transporting agent
  • type and composition of sediment
  • flow characteristics of transporting agent
  • site of deposition
  • types and abundance of organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lithification definition .

A

Process of converting sediment to sedimentary rock

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

Lithification process

A

1) Deposition forms unconsolidated pile of sediment - lots of pore space
2) As pile grows thicker weight compacts lower layers - reduces pore space
3) Grains become cemented by:
- remobilisation of some minerals through pressure solution
- water moving through pores precipitating minerals
- commonly quartz or calcite
- also iron oxides, clay minerals

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

What are the five principal groupings of sedimentary rocks

A

1) Clastic
2) Biogenic/bioclastic
3) Organic
4) Chemical
5) Volcaniclastic

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

Clastic rocks

A
  • made of clasts; detrital origin
  • clasts are pieces of mineral or pre existing rock formed from weathering
  • e.g. sandstone, siltstone. breccia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Biogenic/bioclastic rocks

A
  • made of particles originally produced by living organism
  • generally broken or complete shell material
  • e.g. limestone, chalk, chert
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Organic rocks

A
  • made of compressed and heated plant material

- e.g. peat, coal

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

Chemical rocks

A
  • made from precipitated dissolved particles, Ca, SiO2, FeO etc.
  • e.g. evaporite, ironstone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Volcaniclastic rocks

A
  • as for clastic but significant proportion of clasts are of volcanic origin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is clast size determined

A

Energy of transporting medium determines clast size i.e. the closer to source the more coarse

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

Relationship between clast shape and transport distance and energy of depositional environment

A

Roundness of clast increases with transport distance and energy of depositional environment

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

Examples of clastic sedimentary rocks - Conglomerate

A
  • contains large rounded clasts

- space between clasts contains much smaller grains and/or cement

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

Examples of clastic sedimentary rocks - Breccia

A
  • contains large, angular clasts

- space between clasts contains much smaller grains and/or cement

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

Examples of clastic sedimentary rocks - Sandstone

A
  • sand-sized clasts

- can see clasts with naked eye

17
Q

Examples of clastic sedimentary rocks - Siltstone

A
  • silt sized clasts

- cannot see clasts with naked eye

18
Q

Examples of clastic sedimentary rocks - Claystone

A
  • clay-sized clasts

- cannot see clasts with naked eye

19
Q

Examples of clastic sedimentary rocks - Mudstone/shale

A
  • mix of silt to clay-sized clasts
  • cannot see clasts with naked eye
  • mudstone breaks into blocks
  • shales split easily along parallel planes
20
Q

Examples of biogenic sedimentary rocks - limestone

A
  • composed primarily of calcium carbonate
  • can form from the accumulation of shell material
  • can look crystalline
21
Q

Examples of biogenic sedimentary rocks - chalk

A
  • very fine-grained limestone

- formed from calcium carbonate skeletal remains of marine plankton

22
Q

Examples of biogenic sedimentary rocks - coal

A
  • forms from plant debris
  • accumulates in swampy environments
  • burial drives off volatiles, compacts
  • higher grade means fewer volatiles
23
Q

Examples of biogenic chemical rocks - Evaporites

A
  • form from the evaporation of mineral rich water

- form in very arid climates

24
Q

How and why does bedding occur

A
  • formed during lithification process
  • defined by changes in grain size, composition or colour
  • upper and lower surfaces of a bed are known as bedding planes
  • represent change in environment of deposition
  • can be variable thickness

CIVIL 220 (9 decks)

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