Sedimentary system

Question 1

Why is sedimentology important?

Answer 1

• earth history
• origins of life
• mineral and fuel resources
• Geohazards
• sedimentary processes
• Impacts of climate change

Question 2

What is a rock?

Answer 2

Any mass of mineral matter weather consolidated or not which forms part of the earths crust

Question 3

What is a mineral?

Answer 3

A structurally homogeneous solid of definite chemical composition, formed by the inorganic processes of nature

Question 4

What is a crystal?

Answer 4

A 3D body with symmetrical bounding surfaces, constant angular relationships, arising from the inherit regular atomic structure of the substance.

Question 5

Examples of physical weathering? (4)

Answer 5

• Freeze thaw
• Differential expansion of minerals as they heat in the sun
• action of plant roots and micro-organisms
• Abrasion (wind, wave etc)

Question 6

Examples of natural zones of weakness: (2)

Answer 6

• Jointing

- Bedding planes

Question 7

What controls a rocks resistance to weathering in relation to it’s chemistry? (2)

Answer 7

• atomic structure

- chemical stability

Question 8

What is an ION?

Answer 8

When atoms or molecules gain or loose an electron

Question 9

What is the formula for the ions halite go to when disolved in water?

Answer 9

NaCl= Na+ +Cl-

Question 10

What is an ANION?

Answer 10

Atom/molecule gains an electron and so becomes negatively charged i.e Cl-

Question 11

What is a CATION?

Answer 11

Atom/molecule looses an electron and so becomes positively charged i.e Na+

Question 12

CaCO3+H2O+CO2 ->

Answer 12

Ca2+ +2HCO3-

Question 13

Calcium carbonate +water + Carbon dioxide

Answer 13

Calcium Cation + bicarbonate anion

Question 14

State the order in witch the minerals in granite weather

Answer 14

1) biotite mica
2) Plagioclase f’spa (white)
3) Orthoclase f’spa (pink)
4) Quartz

Question 15

What minerals are present in Arkose?

Answer 15

Othoclase feldspar and Quartz

Question 16

What is there no Plagioclase feldspar in Arkose?

Answer 16

• It reacts with acid in rain water
• some atoms are dissolved and turned to clay
• fine clay particles are washed away large quartz and orthoclase are left behind

Question 17

What is the relationship between the level a climate supports life and chemical weathering?

Answer 17

the more a climate supports live the higher the weathering

Question 18

What climate would you expect a)fast b) slow chemical weathering?

Answer 18

a) warm and humid b) cold and dry

Question 19

what is mass wasting?

Answer 19

Mass wasting is the down slope movement of a mass of sediment and/or rock due mainly to the force of gravity

Question 20

Mass movement of consolidated rock:

Answer 20

• Rock fall
• Rock slide
• Rock avalanche

Question 21

Mass movement of unconsolidated material:

Answer 21

• Creep
• Slump
• Debris slide
• Debris avalanche
• Earthflow
• mudflow
• solifluction
• Debris flow

Question 22

What is a rock slide?

Answer 22

Mass of rock slides down as one unit

Question 23

What is Rock avalanche? Where do these happen?

Answer 23

Rocks flow downhill, Himalayas

Question 24

What is creep?

Answer 24

Slow movement of soil or other debris (1-10mm/year)

-Cause issues interperating dip of rocks

Question 25

What is slump?

Answer 25

Slow slide of unconsolidated material mooving as an unit

Question 26

what is a mudflow?

Answer 26

Mud flows move very fast and contain large amounts of water

Question 27

what is debris flow?

Answer 27

Contain material coarser than sand and move at afew tens of km/hour

Question 28

What makes a slope a) stable b) unsatble?

Answer 28

a) Driving force < /=Resting force | b) driving force > resting force

Question 29

What are the driving forces of a slope?

Answer 29

Shear stress: Steepness of slope, mass of material

Question 30

What are the resisting fores of a slope?

Answer 30

Slope material, water content

Question 31

What 3 factors determine weather a slope will undergo mass movement?

Answer 31

1) slope materials- loose unconsolidated material is more susceptible than solid bedrock 2) water content- a small amount of water can bind sediments together, to much water will allow sediments to flow 3) steepness of slope- 'angle of repose' the maximum angle at which a slope is stable

Question 32

What can trigger mass movements? (4)

Answer 32

1) earthquakes- liquefaction: shaking saturated sediments transforming them into a fluid state 2) heavy rain: saturates slope material 3) Damn construction- saturate slopes 4) Steep road cuttings- cut steeper than angle of repose

Question 33

Vaiont damn reservoir 1) Where was it? 2) When was it built? 3) what indicaters were there before the mass movement? 4) when did the mass movement occur? 5) how many people were killed? 6) what kind of mass movement was it and what did it trigger?

Answer 33

1) Alpine valley italy 2) 1959 3) Cracked and deformed limestone and shale valley walls, aincient slide scar above resevoir, small rockslide in 1960 4) 1963 5) 3,000 6) landslide water spilled over damn (200m wave)

Question 34

describe a laminar flow? | What size particles can it carry?

Answer 34

streemiles do not cross; no mixing between layers, slow flow, high viscosity, thin sheet of fluid. Carrys only clay size particles

Question 35

describe a turbulent flow?

Answer 35

Streams cross with extensive mixing of fluid, fast flow, low viscosity thick body of water. Can carry clay size up to cobble size

Question 36

What are the two ways current flowing over sand and silt can carry water?

Answer 36

in a 'suspended load' or in the 'bed load' sliding and rolling along the bottom