Sedimentary 1

Question 1

Grain Sizes

Answer 1

Coarse- >2mm
Medium- 0.06-2mm
Fine- <0.06mm

Question 2

Weathering

Answer 2

Chemical- hydrolysis, carbonation, oxidation, solution
Physical- insolation, frost

Question 3

Erosion

Answer 3

abrasion, attrition

Question 4

Minerals

Answer 4

quartz+muscovite- inactive
clay- koalinite, chlorite, illite
soluble salts- K+, Na+, Ca2+, Mg2+
Iron oxides- ferric hydroxide, ferrous oxide

Question 5

Heavy Minerals

Answer 5

gold, diamond, platinum, heamatite, rutile, corundum, zircon, garnet, magnetite

Question 6

Transportation

Answer 6

suspension, saltation, traction

Question 7

High Energy Environments

Answer 7

energetic waters, river floods, alluvial fan, shingle beach

Question 8

Low Energy Environments

Answer 8

slow movement, lakes, deltas at high tide, deep sea >20m

Question 9

Grain shape

Answer 9

short transportation
very angular
angular
sub angular
sub rounded
rounded
well rounded
long transportation

Question 10

Grain Sorting

Answer 10

well sorted- <10x
moderately- <100x
poorly sorted- <1000x

Question 11

Sedimentary Rocks

Answer 11

Breccia- alluvial fan, coarse/medium, v. angular- sub angular, poorly
Conglomerate- shingle beach, coarse/medium, rounded- w. rounded, poorly
Arkose- braided river, medium, sub angular-sub rounded, moderately
Orthoquartzite- desert sand, medium/coarse, w. rounded, moderately
Greywake- turbidity current, fine/medium, v. angular, sub angular, poorly

Question 12

Limestone Rocks

Answer 12

Oolitic- tropical beach, medium, well rounded, poorly
Chalk- deep temperate sea, fine, well sorted
Bioclastic- shallow tropical sea, coarse/fine, fossils, micrite, angular fragments, poorly

Question 13

Sedimentary Structures

Answer 13

bedding, beds, lamination, ripples<10cm, dunes>10cm(desert >5m, river 0.2-0.5m, beach ripples 0.1-0.2m, shallow marine 0.5-5m), cross bedding, graded bedding, desiccation cracks

Question 14

Mature Rocks

Answer 14

stable minerals, generally sorted, mainly rounded/sub rounded
e.g. orthoquartzite, siltstones, some conglomerates

Question 15

Immature Rocks

Answer 15

range of mineral compositions, lithic fragments, poorly sorted, angular
e.g. breccia, arkose, greywake, some conglomerates

Question 16

Turbidity Structures

Answer 16

flute casts- bulbous mark
groove marks- linear ridge with tool at the end
tool marks- impact scars
load casts- sediment above penetrates underlying less dense area, makes flame structures

Question 17

Diagenesis

Answer 17

cementation- chemical compounds precipitate in pore space from groundwater and bonds grains together
recrystallisation- turns into crystal form from heat and pressure
pressure solution- applied force at contact points allows grains to fuse together