Lecture 2 weathering

Question 1

Processes of Sedimentary rock cycle

Answer 1

1. Transportation
2. Depostion: when energy becomes insufficent to move sertain paricals
3. Lithification: –> three steps together are termed Diagenessis
   a) Compaction
   b) Cementation: chemical cement from trapped water and circulating water
   c) Recrystallization: groth of grains in responce to new equilibrium condictions

Question 2

Mud Rock

Answer 2

Combo of silt and caly

shale is platty / fissile mud rock

Question 3

Weathering

Answer 3

Physical or chemical break down of rocks

Question 4

erosion

Answer 4

The movment of weathered material

Question 5

Mechanical Weathering

Answer 5

First joints form in rocks or eath surface and then they are widdened by secondary processes like freez thaw action

Question 6

what does stress release lead to (when a rock gets un barried)

Answer 6

Stress relieas leads to exfoliation

Question 7

Insolation

Answer 7

Result of differential thermal expantion and contraction

Question 8

Secondary processes

Answer 8

occures after jointing: freez thaw cycles and salt wedging in arid climets
organismal activity

Question 9

secondary process: organismal activity

Answer 9

Burrowing, roots

Chliona Chips, lucked out when sponges boar into rocks (the chips/ bits of sand have conquoidal fractures)

Question 10

Talus

Answer 10

Product of mechanical weathering and it piles up, usually into cones of talus

Question 11

Simple solution

Answer 11

Chemical Weathering: Contact between soluble minerals and water
EX:Salt solution , Alberta in Divonian, reafs were formed and evaporites formed called the Prairy Evaporites. From devonian on it was chemically aulted by ground water. During lower cretaceous the McMurry formation was deposited. The Prariy evaporites were disolved and the McMarry foration foled over and traped oil.

Rollover anti cline
caused oil sands
could not have happianed with out prariy evaporites

Question 12

Hydration

Answer 12

Loss or gain of water that effects the mechanical properties and the volume of a mineral
CaSO4.H2O –> CaSO4 + H20

Question 13

Hydrolysis

what cases Karst caves

Answer 13

Free H+ that racts with the rock in solution to produce an acid or very soluble products

Cat ion substitution of hydrogen ions in solution in acid water (rain water or ground water)
Most rain water is acidic when the water reacts with carbon dioxide

CO2 + H20 –> H+ + HCO3

with that free hydogen ion it can react with CaCO3 to make very soluble products

H+ ions can also alteration into a diffrent solid with different mechanical properties
EX: Orthoclase weathers to Kaolinite

Question 14

Oxidation

Answer 14

When an atom or ion losses electrons

On eaths surface its mostly carried out by O2 dissolved in water

Question 15

What are the controls of chemical weathering

Answer 15

1. Temp
2. Moisture–> most chemical wethering processes require water
3. pH –> Hydrolysis needs H+ ions
4. Redox potential eH –> describes liklihood of the gain or loss of electrons

Question 16

Rhizolith

Answer 16

root systems that have been encased in mineral matter

Question 17

Physical weathering peramaters

Answer 17

1. cold climent
2. Drainage –> well draind areas experians more wheathering b/c products need to be removed so equalibriam is not reached
3. Relief
4. Composition, grain size
   finer grained rocks weather faster b/c of higher surface area

Goldich’s mineral stability series is just the opposit of Bowen’s reaction series (Old People Are Borring) olivin piroxen amphibole bioit,