Deck 7: Sedimentary Rocks

Question 1

Which one of the following is not a chemical sedimentary rock or evaporite?

A)shale
B)bedded gypsum
C)oolitic limestone
D)cherty dolostone

Answer 1

A

Question 2

What is the chemical formula for dolomite, the major mineral in dolostones?

A)SiO2
B)CaSO4 · 2H2O
C)CaMg(CO3)2
D)NaCl

Answer 2

C

Question 3

Which of the following sedimentary rocks would you expect to have originally been deposited by fast- moving streams?

A)mudstone
B)greywacke
C)conglomerate
D)oolitic limestone

Answer 3

C

Question 4

, a common mineral found in igneous rocks, is the most abundant mineral in detrital sedimentary rocks.

A)Orthoclase
B)Calcite
C)Quartz
D)Biotite

Question 5

Which characteristic is absolutely necessary for a sedimentary rock to have potential as a possible reservoir rock for oil or gas?

A)high permeability
B)good stratification
C)chemical origin
D)clastic texture

Question 6

Which of the following is not a type of limestone?

A)coquina
B)travertine
C)chalk
D)arkose

Question 7

Which major component of detrital sedimentary rocks only rarely occurs as a primary mineral in igneous rocks?

A)clays
B)quartz
C)carbonates
D)ferromagnesian minerals

Question 8

Nonclastic textures are common in which of the following sedimentary rocks?

A)cherty conglomerates
B)boulder breccias
C)sandstones
D)limestones

Question 9

are further concentrated in a residual brine after NaCl is crystallized.

A)Potassium, magnesium, and bromine
B)Magnesium, calcium, and sulfur
C)Calcium, sulfur, and titanium
D)Iron, sodium, and chlorine

Question 10

A cherty limestone would contain which major constituents?

A)silica, iron oxide
B)clay minerals
C)iron oxide, calcite
D)silica, calcite

Question 11

cement produces bright- red and yellow colors in some sandstone.

A)Clay
B)Iron oxide
C)Calcite
D)Quartz

Question 12

What is probably the single most important, original, depositional feature in sedimentary rocks?

A)sizes of the sand grains
B)bedding or stratification
C)compaction of the mud and clay
D)degree of lithification

Question 13

A graywacke is .

A)a sandstone with the sand grains embedded in a clay- rich matrix
B)a dark, organic- rich, chemical sedimentary rock containing small crystals of halite
C)a dark- gray, calcite- rich mudstone or shale containing pyrite
D)a limestone with abundant, sand- sized, quartz grains

Question 14

Sedimentary rocks account for about what percentage of the Earth's outermost 10 kilometers of rock (first percentage). Also, what percentage of the Earth's continental area is covered by sedimentary rocks (second percentage)?

A)3.5% and 100%
B)85% and 100%
C)65% and 10%
D)5% and 75%

Question 15

is a form of calcium carbonate.

A)Lignite
B)Chert
C)Travertine
D)Gypsum

Question 16

Oolitic limestone is most likely to form in what type of depositional environment?

A)deep, marine waters below most wave action
B)shallow, clear, marine waters with vigorous current activity
C)acidic, organic- rich waters in freshwater swamps and bogs
D)quiet, muddy, lagoons and bays

Question 17

Which of the following sedimentary features would typically be found in shales but not in sandstones?

A)bedding
B)mud cracks
C)cross stratification
D)ripple marks

Question 18

Detrital grains of which mineral(s)are extremely rare in detrital sediments? Why?

A)Feldspars; they occur only in granites.
B)Calcite; it is soft and relatively soluble.
C)Clays; they are rare in soils and regolith.
D)Quartz; it is very hard and insoluble.

Question 19

Which statement concerning sedimentary rocks is NOT true?

A)They may contain fossils that provide clues about ancient life forms.
B)They are composed of particles and constituents derived from weathering and erosion of other rocks.
C)They were originally deposited at depth below the bottom of the sea.
D)They probably show some evidence of stratification.

Question 20

is the most common type of chemical sedimentary rock.

A)Limestone
B)Quartz sandstone
C)Chert
D)Phosphate rock

Question 21

Which is the most common chemical sedimentary rock?

Question 22

Detrital sedimentary rocks are classified (named)based on the .

A)degree of compaction and lithification
B)compositions of soluble minerals
C)colors of the cementing minerals
D)grain sizes of the detrital particles

Question 23

Which of the following best describes bedded gypsum and halite?

A)varieties of coal and peat
B)evaporates
C)detrital sedimentary rocks
D)varieties of dolostone

Question 24

Which type of sediment undergoes the most compaction as it lithifies to sedimentary rocks?

A)marine mud
B)coarse gravel
C)desert dune sand
D)reef limestone

Question 25

Red, brown and yellow sandstones are cemented by oxides of .

Question 26

What is the most characteristic, original, depositional feature preserved in sedimentary rocks?

Question 27

Which of the following applies to the basic constituents of halite, gypsum, and sylvite?

A)transported and deposited as mud- sized particles
B)transported as dissolved ions; deposited by evaporation
C)transported as dissolved ions; deposited as detrital mud
D)transported as detrital mud; deposited by evaporation

Question 28

Which evaporite sedimentary rock, composed of calcium sulfate, is an important component of plasters and wallboard?

Question 29

Which of the following describes the correct order for relative solubility of minerals in sedimentary rocks?

A)Evaporate minerals are more soluble than calcite and quartz.
B)Evaporate minerals are more soluble than quartz and less soluble than calcite.
C)Evaporate minerals, quartz, and calcite all have the same relative solubility.
D)Evaporate minerals are less soluble than quartz and calcite.

Question 30

Coal beds originate in .

A)shallow lakes in a dry, desert region
B)freshwater coastal swamps and bogs
C)channels of fast- moving streams
D)deep, marine basins below wave action

Question 31

sandstone contains abundant feldspar, suggesting that the sand was derived by weathering and erosion of granitic bedrock.

A)Lignitic
B)Quartz- rich
C)Oolitic
D)Arkosic

Question 32

What term describes the complex, original stratification pattern seen in sandstones deposited in ancient sand dunes?

Question 33

Which variety of limestone consists mainly of sand- sized, mostly spherical grains of calcium carbonate precipitated in shallow, marine waters?

Question 34

Which of the following sedimentary features can each be used to determine paleocurrent directions?

A)fossils and mud cracks
B)grain size sorting and ripple marks
C)mud cracks and ripple marks
D)ripple marks and cross stratification

Question 35

Flint, chert, and jasper are microcrystalline forms of _.

A)halite (NaCl)
B)quartz; (SiO2)
C)calcite (CaCO3)
D)hematite (Fe2O3)

Question 36

Sandstones are lithified mainly by cementation. What is the major process involved in the lithification of shales?

Question 37

Which type of limestone consists mainly of tiny, marine fossils composed of calcite?

A)dolostone
B)chalk
C)coquina
D)chert

Question 38

What is the main difference between a conglomerate and a sedimentary breccia?

A)Breccia clasts are the size of baseballs; conglomerate clasts are larger.
B)Breccia has a compacted, clay- rich matrix; conglomerate has no matrix.
C)Breccia clasts are angular; conglomerate clasts are rounded.
D)A breccia is well stratified; a conglomerate is poorly stratified.

Question 39

is not a common cementing agent for sandstones.

A)Quartz
B)Fluorite
C)Calcite
D)Iron oxides

Question 40

Flint and jasper are microcrystalline forms of .

Question 41

What is the general name for microcrystalline quartz in sedimentary rocks?

Question 42

is composed mainly of lithified, organic debris that accumulated in ancient, heavily forested swamps.

Question 43

Which property of sediment describes the range of different grain sizes in a detrital sedimentary rock?

Question 44

The study of depositional environments in sedimentary rocks is critical to understanding Earth's history. What features or characteristics of sedimentary rocks are unique to particular environments? What features are found in a variety of environments and are therefore less definitive for interpreting paleoenvironments?

Question 45

What are the three, most common, cementing agents for sandstones?

Question 46

Considering the factors that influence the formation of sedimentary rocks, how might sedimentary rocks be different on another planet such as Mars or Venus? What about similarities?

Question 47

The sedimentary rocks, salt and gypsum, are deposited by what process?

Question 48

What is the most abundant mineral in detrital sedimentary rocks?

Question 49

Fossils often provide valuable information about climatic conditions of the geologic past. How else might a geologist infer ancient climatic conditions using sedimentary rocks? (Hint: Think in terms of the conditions necessary to form certain rocks and also features/structures found in sedimentary rocks.)