Sedimentary Rocks

Question 1

Define sediments

Answer 1

Particles of minerals that often settle on the top of mineral beds.

Question 2

Define Siliciclastic sediment

Answer 2

Grains of feldspar and quartz

Or basically minerals that have Si in formula

Question 3

Define lithify

Answer 3

Hardening

Question 4

Define compaction and cementation

Answer 4

Compaction- reduction in volume of sediments resulting from weight of newly deposited sediments above
Cementation- Sediment being “glued” together via mineralization, typically calcite and quartz from groundwater fluid

Question 5

Formation of sedimentary rocks

Answer 5

Formed from sediment, deposited in water or air

Usually settles as layers or bedded

Question 6

Define Carbonate sediments

Answer 6

Grains of calcite and dolomite
Or minerals that have C03 in the formula
Pyroclastic

Question 7

Process of the formation of sedimentary rocks starts from what

Answer 7

Weathering and Erosion

Question 8

Process of formation

Answer 8

Weathering —> transportation—>deposition and lithification *****in a hole or basin (lake or ocean basin

Question 9

Sedimentary rocks constitute

Answer 9

Only 7% of the earths crust by volume however

Covers 75% of the earths surface

Question 10

What are modes of Transportation of loose sediment

Answer 10

Wind, water, glacial ice
Coarsest particles are close to the surface
The greater the distance of transport, the smoother or more rounded grains become

Question 11

What are the three main Types of sedimentary rocks

Answer 11

Clastic sediments
Biochemical (carbonate) sediments
Chemical sediments

Question 12

Clastic sediments

Answer 12

Rocks made up of small fragmented pre-existing rocks. Are then naturally weathered and transported, ends with lithification. Clastic = Detrital

Question 13

Biochemical sediments

Answer 13

Formed from organic processes that involve living organisms producing the sediments. E.g. Limestone & Dolostone

Question 14

Chemical sediments

Answer 14

precipitated directly from water (evaporation)

Question 15

Define lithification

Answer 15

Is the conversion of sediments into rock. The following diagenetic processes may be involved
Compaction
Cementation

Question 16

Define diagenetic

Answer 16

Physical, chemical or biological alteration of sediments into sedimentary rock at relatively low temperatures and pressures

Question 17

Sedimentary rock classification

Answer 17

Generally determined by size of grain and roundness

Location and ecological can also determine types

Question 18

Clastic sedimentary rocks

Answer 18

Classical = detrial

Classified by size or particle

Question 19

What is the Wentworth scale

Answer 19

Grain diameter

Question 20

Angular and rounded sediments rocks

Answer 20

Breccia and conglomerate

Question 21

What rock name is greater than .0625mm

Answer 21

Shale

Question 22

What is the study of the provenance

Answer 22

reconstruct and to interpret the history of sediment from parent rocks at a source area

Question 23

Biochemical sedimentary rocks traits

Answer 23

Primarily found in oceans
Limestone and Dolostone are the main rocks
They are precipitation of dissolved ions

Question 24

Limestone

Answer 24

Composition of Calcium Carbonate

The primary source of calcite is marine organisms shells

Question 25

Most important feature of carbonate rocks

Answer 25

Texture | Is it carbonate mud or carbonate mud with skeletal materials

Question 26

Carbonate reefs

Answer 26

A reef complex on a carbonate shelf or platform, | Important setting of deposition of limestone

Question 27

Define fore reef, test question***

Answer 27

A fore reef is a platform on the edge of a coral reef made up of mostly dead organisms and calcite

Question 28

Where do coral reefs occur

Answer 28

Needs clear, warm, shallow water | Need water temperatures of 30 degrees

Question 29

Atoll formation

Answer 29

1) Underwater volcano pierces ocean surface 2) Coral reef forms around thre volcanic island 3) Fringing reef surround the sinking island 4) Barrier reef protects newly formed lagoon

Question 30

Chemical sedimentary rocks

Answer 30

Chemical sedimentary rock forms when mineral constituents in solution become supersaturated and inorganically precipitate.

Question 31

Biochemical rock | Chert or Flint

Answer 31

Small particles of silica, often from shells of microscopic organisms like radiolarian So chert is not a carbonate but a silica Deep water oozes

Question 32

Organic sedimentary rocks

Answer 32

Think coal. *****

Question 33

Sedimentary structures

Answer 33

Layers = beds/strata

Question 34

Graded bedding

Answer 34

changing (decreasing) energy = Fining up?

Question 35

Formation of cross bedding and ripples ***test question

Answer 35

Asymmetrical ripples form in a unidirectional flow. Symmetrical ripples are the result of an oscillating back-and-forth flow typical of intertidal swash zones.

Question 36

How much of the earths core is made up of sedimentary rocks*****test question

Answer 36

75%

Question 37

What are the three main categories of sedimentary rocks **** test question

Answer 37

Silicilastic, biochemical and chemical