Deck 7: Pages of Earths Past: Sedimentary Rocks

Question 1

The removal of detritus from weathered rock at an outcrop is termed ____________.

A)deposition
B)erosion
C)weathering

Answer 1

B

Question 2

Unlike physically precipitated chert,biochemical chert ____________.

A)is bedded (layered)
B)is made up of the skeletons of radiolaria and foraminifera
C)does not occur as small nodules within bodies of limestone
D)All of the above are correct.

Answer 2

D

Question 3

It is unusual for ____________ to carry grains larger than sand.

A)ice
B)water
C)wind

Answer 3

C

Question 4

Chemical weathering takes place most rapidly in environments that are ____________ and ____________.

A)cool;dry
B)cool;wet
C)warm;dry
D)warm;wet

Question 5

Chemical and biochemical rocks are classified primarily on the basis of ____________.

A)grain size
B)degree of sorting
C)angularity
D)mineral composition

Question 6

Biochemical limestones are dominated by carbonate mud and fragments of ____________.

A)siliceous shells of planktonic diatoms and foraminifera
B)calcitic and aragonitic skeletons of marine invertebrates
C)the phosphatic bones of fish
D)the organic breakdown products of wood from trees

Question 7

When limestone becomes chemically altered so that half of the calcium atoms are replaced by magnesium,the resultant rock is termed ____________.

A)agate
B)dolostone
C)jasper
D)travertine

Question 8

Lithified detritus (breakdown products of preexisting rocks)forms which kind of sedimentary rock?

A)biochemical
B)chemical
C)clastic
D)organic

Question 9

A fine-grained clastic rock that splits into thin sheets is ____________.

A)mudstone
B)shale
C)sandstone
D)arkose

Question 10

Cemented shells of marine organisms form which kind of sedimentary rock?

A)biochemical
B)clastic
C)organic

Question 11

Physical precipitation of gypsum due to evaporation of seawater produces which kind of sedimentary rock?

A)biochemical
B)chemical
C)clastic
D)organic

Question 12

Which transport medium carries the largest particles?

A)ice
B)water
C)wind

Question 13

The breakdown of exposed rock into small fragments and dissolved ions is termed ____________.

A)deposition
B)erosion
C)weathering

Question 14

Clastic sedimentary rocks are primarily classified on the basis of ____________.

A)grain size
B)degree of sorting
C)angularity
D)mineral composition

Question 15

Compaction and cementation of grains occurs during ____________.

A)erosion
B)lithification
C)transport
D)weathering

Question 16

Physically precipitated (chemical)limestone that forms in caves is termed ____________.

A)agate
B)dolostone
C)jasper
D)travertine

Question 17

Grains become rounded primarily during ____________.

A)weathering at outcrop
B)erosion
C)transportation
D)deposition

Question 18

The majority of the rocks that occur at the surface of Earth are ____________.

A)intrusive igneous rocks
B)extrusive igneous rocks
C)sedimentary rocks
D)metamorphic rocks

Question 19

Consult the figure below.The difference between breccia and conglomerate is that conglomerate ____________.

A)is finer grained than breccia
B)is coarser grained than breccia
C)possesses more angular grains than breccia
D)possesses more rounded grains than breccia

Question 20

Two major sources of energy,coal and oil shale,are considered ____________ sedimentary rocks.

A)clastic
B)biochemical
C)organic
D)chemical

Question 21

If a geologist found preserved mud cracks,he or she could conclude that the environment in which they formed ____________.

A)was once covered in wet mud
B)was once covered in hexagonal plates with curled-up edges
C)has been covered in sediment
D)All of the above are correct.

Question 22

What type of sediment is found in lake bottoms?

A)gravel
B)sand
C)silt
D)clay

Question 23

If water is the transport mechanism of sediment,the grain size of sedimentary deposits most closely indicates the ____________.

A)geographic extent of the weathering source rock at outcrop
B)average velocity of the water from the time of erosion until deposition
C)velocity of the water at the moment the sediment settled to the bottom

Question 24

Glacial till is composed of ____________ sized particles.

A)clay- to boulder-
B)mostly boulder-
C)mostly clay-
D)mostly sand-

Question 25

Consult the figure below.Breccia and conglomerate most likely formed from deposits in a ______________.

A)dessert
B)lake
C)mountain stream

Question 26

Which environment would most likely produce sedimentary deposits characterized by very well-sorted,very well-rounded grains that are nearly pure quartz?

A)river
B)glacier
C)beach
D)alluvial fan

Question 27

As compared to arkose,quartz sandstone ____________.

A)is more mature
B)does not contain significant amounts of feldspar
C)is likely to be found farther away from weathering granitic source rock
D)All of the above are correct.

Question 28

Topset,foreset,and bottomset beds are indicative of ____________.

A)alluvial fans
B)lake bottoms
C)deltas
D)deep-marine settings

Question 29

Swamps,channels,floodplains,and submarine slopes all play a role in the development of ____________.

A)deltas
B)marine deltas
C)alluvial fans

Question 30

Ripples,dunes,and cross bedding are sedimentary structures that can be used to determine _____________.

A)wind direction
B)current direction
C)past environments
D)All of the above are correct.

Question 31

Consult the figure below.Graded beds tell a geologist that a _____________.

A)turbidity current deposited these beds,depositing finer material first
B)turbidity current deposited these beds,depositing coarser material first
C)slurry deposited these beds with little sorting
D)density current deposited these beds,depositing coarser material first

Question 32

Siltstone or mudstone containing marine fossils likely formed in a ___________ environment.

A)shallow-marine
B)deep-marine
C)marine-delta
D)coastal-beach

Question 33

Consult the figure below.Distinct internal laminations that are inclined at an angle to the boundary of the main sedimentary layer are called ___________.

A)graded beds
B)cross beds
C)horizontal beds

Question 34

A clastic rock comprised of sand-sized grains derived from the physical weathering of granite and containing a sizable proportion of feldspar is termed ____________.

A)metasandstone
B)lithosandstone
C)graywacke
D)arkose

Question 35

Stratification refers to ____________.

A)the development of layering within sedimentary rocks
B)the act of deposition of sediment that will ultimately form sedimentary rock
C)physical and chemical alterations,including compaction and cementation,that occur as sediment is transformed into rock

Question 36

Sedimentary deposition is a continuous process: rivers,lakes,and the ocean deposit sediments nonstop at a fairly constant rate.

Question 37

Geologists call individual layers of sedimentary rocks _____________ ,whereas several of them together are called ____________.

A)beds;strata
B)strata;beds

Question 38

Consult the figure below.Limestone is most likely formed in which of the following environments?

A)shallow-marine clastic
B)shallow-marine carbonate
C)marine delta
D)deep marine

Question 39

Waves cause beach sand to be ____________.

A)well rounded
B)poorly sorted
C)well sorted
D)A and B are both correct.
E) A and C are both correct.

Question 40

Asymmetric ripples are indicative of unidirectional flow,whereas symmetric ripples are indicative of flow in multiple directions.

Question 41

As compared with metamorphism,diagenesis ____________.

A)means exactly the same thing
B)takes place at lower temperatures and pressures
C)takes place at higher temperatures and pressures
D)takes place at greater depths that are well within the mantle

Question 42

Beach sediments would travel ___________ the ocean during a transgression and ___________ the ocean during a regression.

A)toward;away from
B)away from;toward

Question 43

Which environment would most likely produce sedimentary deposits characterized by poorly to moderately sorted,angular to subangular grains that consist of feldspar,quartz,and lithics (rock fragments)?

A)river
B)glacier
C)beach
D)alluvial fan

Question 44

Diagenesis requires ____________.

A)deep burial
B)high temperatures and pressures
C)warm groundwater
D)All of the above are correct.

Question 45

What effect would plants have on a sand dune environment?

A)encourage sand movement
B)deter sand movement
C)Plants have no effect on a sand dune environment.

Question 46

What causes the formation of an alluvial fan?

A)load capacity
B)friction
C)decreased velocity
D)All of the above are correct.

Question 47

Because the velocity of sediment settling (deposition)is positively related to grain size for waterborne sediments,fluvial deposits are more likely than glacial deposits to ____________.

A)be well sorted
B)include coarse grains,such as cobbles
C)include fine grains,such as clay
D)have angular grains

Question 48

Similar sediment and depositional thickness can be found in all sedimentary basins.

Question 49

A well-sorted sandstone with asymmetric ripples was most likely deposited as sand by a ____________.

A)river
B)glacier
C)beach
D)alluvial fan

Question 50

Diagenesis refers to ____________.

A)the development of layering within sedimentary rocks
B)the act of deposition of sediment that will ultimately form sedimentary rock
C)physical and chemical alterations,including compaction and cementation,that occur as sediment is transformed into rock

Question 51

If a geologist were to dig below the current beach and find offshore sediments underlain by beach and swamp deposits then he or she could conclude that ____________ has occurred.

A)transgression
B)regression

Question 52

Pulling a block of clay apart,resulting in the middle portion thinning and sinking,is an adequate analogy for ___________.

A)passive margins and subsidence
B)foreland basins and diagenesis
C)rift basins and subsidence
D)intercontinental basins and diagenesis

Question 53

What is the difference between the formations of chalk versus chert?

A)depositional environment
B)source material
C)A and B are correct.
D)None of the above are correct.

Question 54

In which of the following phenomenon are sediment records NOT preserved?

A)transgression
B)regression

Question 55

Sea level rises locally,and marine sediments are deposited on top of terrestrial sediments during events termed ____________.

A)regressions
B)transgressions
C)divarications

Question 56

Death Valley,part of the Basin and Range Province,has been sinking due to the weight of continuously accumulating sediment shed from the Black and Panamit Mountains that border the valley.What phenomenon is this an example of and what depositional environment is created by the sediment deposition?

A)regression and deltas
B)subsidence and deltas
C)regression and alluvial fans
D)subsidence and alluvial fans