Sedimentary Rocks

Question 1

detrital

Answer 1

also known as terrigenous sediments

• detrital rocks are formed by the accumulation and subsequent lithification of mineral and rock particles derived from broken rocks and of skeletal remain of dead organisms
• these rocks are always stratified

Question 2

what type of rocks make up 80-85% of the stratificrafic record

Answer 2

• clastic rocks

Question 3

what type of rocks/sediments make up 10-15% of stratigraphic record

Answer 3

carbonate sediments and rocks

Question 4

common sedimentary rocks

Answer 4

Dentrial/clastic sediments: silicates (Qtz, feldspar, clay minerals)

chemical sediments: carbonates (calcite and dolomite; evapourites: gypsum, halite and sylvite)

Question 5

less common sedimentary rocks

Answer 5

heavy minerals: gold, zircon, garnet

Question 6

What is the concept of maturity (5)

Answer 6

• stability of minerals
• rock fragments
• rounding and angularity
• sorting (same size or different size grain)
• removing of unstable ingredients

Question 7

rounding

Answer 7

implies textural maturity

Question 8

compositional maturity

Answer 8

degree to which sediments lack both feldspar and lithic fragments [mature sands are qtz rich]

Question 9

the mineralogy of sedimentary rocks is dependant upon

Answer 9

mineralogy of source rock

weathering

Question 10

what makes red sandstone red?

Answer 10

fe, Iron

- a thin coating of iron surrounding the qtz grain like the skin on an apple

Question 11

chalk vs limestone

Answer 11

chalk is mainly made up of aragonite and NOT calcite

Question 12

biochemical sediments

Answer 12

composed of fossilized remains of plants or animals.