Lab 3: Sedimentary Rocks

Question 1

Breccia

Answer 1

framework clasts are angular

gravel or larger angular clasts surrounded by sand/mud particles

poorly sorted

Question 2

Chert

Answer 2

you can not see the individual grains at all - appears very smooth
cryptocrystalline quartz

conchoidal fracture
hardness = 7

Question 3

Conglomerate

Answer 3

framework clasts are rounded

gravel or larger rounded clasts surrounded by sand/mud particles

poorly sorted

Question 4

Dolostone

Answer 4

look for more beat up railway ballast rock (people wrecking it to make powder)
will weakly react with acid

calcite

Question 5

Fossiliferous Limestone

Answer 5

look for visible fossils
will react with acid

calcite

Question 6

Limestone

Answer 6

look for railway ballast rock
will react with acid
calcite

Question 7

Mudstone

Answer 7

grains are too small to be seen with a hand lens
massive or blocky in nature
feels smooth

mud sized grains

micas and clays

Question 8

Potash

Answer 8

look for mostly pink crystal texture
sylvite and halite

crystalline texture

Question 9

Rock Salt

Answer 9

halite - literally just halite
white crystal texture

crystalline texture

Question 10

Sandstone

Answer 10

speckled salt and pepper-like appearance

mixture of quartz and feldspar with lithics

sand-sized grains
moderately to well sorted
rounded

Question 11

Shale

Answer 11

grains are too small to be seen with a hand lens
breaks into sheets or thin layers
(Fissile, cleavage is wrong)
feels smooth

micas and clays

mud-sized grains

Question 12

biochemical sedimentary rocks

Answer 12

dolostone, limestone, fossiliferous limestone, chert

Question 13

chemical sedimentary rocks

Answer 13

rock salt, potash

Question 14

clastic sedimentary rocks

Answer 14

conglomerate, breccia, sandstone, mudstone, shale

Question 15

controls on soil formation

Answer 15

parent material
time
climate**
plants/animals
topography

Question 16

parent material

Answer 16

the type of material that soil grows on top of, which determines the rate of weathering and the soil fertility

Question 17

time

Answer 17

the longer the soil has been forming the thicker it becomes and less it resembles the parent material

Question 18

climate

Answer 18

most important**
temperature and precipitation are considered among the most influential factors in determine the rate and depth of weathering, particularly at larger scales where climatic differences are more pronounced

Question 19

plants/animals

Answer 19

the physical/chemical properties of soil depend upon the type and abundance of plants and animals which interact with the soil in a variety of complex ways

Question 20

topography

Answer 20

steep slopes impede soil formation due to a decrease in water retention and increase in erosion, thus soils grow much more readily on flat ground

Question 21

o horizon

Answer 21

plant litter, and partly decomposed organic matter

Question 22

a horizon

Answer 22

mainly mineral matter with some decomposed organics

Question 23

topsoil

Answer 23

horizon O and A; they are unsuitable for the construction of infracture

Question 24

E horizon

Answer 24

lEEching horizon. light coloured layer that water percolates through, moving dissolved components and finer particles to lower depths

Question 25

B horizon

Answer 25

material removed from the E horizon through leeching

Question 26

C horizon

Answer 26

partially altered parent material

Question 27

order of the soil layers, top to botto

Answer 27

OAEBC

Question 28

Chernozemic

Answer 28

grassland soil

Question 29

Luvisolic

Answer 29

boreal forest soil

Question 30

crysolic

Answer 30

permafrost instead of soil

Question 31

main minerals found in sedimentary rocks

Answer 31

calcite, dolomite, sylvite, halite, quartz, feldspars, micas, clays