Sedimentary Rocks

Question 0

Chemical

Answer 0

-made from precipitates such as CaCo3 and SiO2

Question 1

Clastic

Answer 1

• made of sediments

- sediment size, shape, and sorting

Question 2

Organic

Answer 2

-made from remains of living organisms

Question 3

Weathering

Answer 3

• Physical: breaks rocks apart
• Chemical: dissolves less stable minerals
• breaking down existing rocks to sediments

Question 4

Erosion

Answer 4

• transportation by water, wind, ice, gravity (below)

- rivers - river load - suspended load, dissolved load, bed load

Question 5

Deposition

Answer 5

• settling of sediments into layers, typically in large body of water
• rates based on sediment size, shape, density

Question 6

Compaction

Answer 6

-flattening of layers due to pressure from layers or sediments above

Question 7

Cementation

Answer 7

• the “gluing together” of sediments using CaCO3 (calcite) or SiO2 (qtz) as they precipitate and become solid from water

Question 8

Stratification

Answer 8

• layers, bed, strata, unit

- stratigraphic columns

Question 9

Crossbedding

Answer 9

• made from wind or water
• layers cross
• sediments are being deposited by fluids (air, wind, water).

Question 10

Ripple marks

Answer 10

• made from the current of running streams/rivers

- show direction of current in river

Question 11

Mud cracks

Answer 11

• water dries up and shrinks sediment layer (contraction)
• arid environment- evaporated water
• form in dry places

Question 12

Fossils

Answer 12

remains of ancient life

Question 13

What is a sedimentary rock?

Answer 13

• formed on surface of earth

- rocks & pieces of once living materials that are cemented together

Question 14

sedimentary rocks are formed from…

Answer 14

• pre-existing rocks
• organisms
• sediments [eg. sand, pebbles, boulders, shells, living material (organic)]

Question 15

Bioclastic

Answer 15

• from living things
• bio: life
  clastic: pieces

Question 16

Size of rocks

Answer 16

• boulder
• cobble
• pebble
• ——— (all larger than sand)
• sand–>sandstone
• silt–>siltstone
• clay–>shale

Question 17

Conglomerate

Answer 17

rounded pebbles that are transported by moving water

Question 18

Breccia

Answer 18

• broken
• angular clasts
• fall down mountain
• not well sorted

Question 19

Poorly sorted

Answer 19

-sediments are different shapes and sizes

Question 20

Well sorted

Answer 20

-sediments are same shape and size

Question 21

Sandstone

Answer 21

• pore space between grains - porus
• permeable - water can pass through
• quartz
• cement:
  
  • silica
  • calcite
  • iron oxide
• feldspar - weathers quickly, sand deposited close to original source

Question 22

Graywacke

Answer 22

-underwater avalanches - turbidity currents

Question 23

Silt and clay

Answer 23

• wet: mud –> mudstone

- pressure from above compresses clay, sheets line up

Question 24

Formation

Answer 24

group of strata

Question 25

Suspended Load

Answer 25

-silt, clay, fine sand

Question 26

Bed Load

Answer 26

-gravel, sand

Question 27

Dissolved Load

Answer 27

-SiO2 + CaCO3

Question 28

Hoodoos

Answer 28

-rock "statues" carved by wind or water

Question 29

U-shaped valleys

Answer 29

carved by glaciers

Question 30

Erratics

Answer 30

boulders chaotically placed by the retreat of a melting glacier