Deck 5: Sedimentation: Rocks Formed by Surface Processes

Question 1

What is the term for the process by which organisms burrow through muds and disrupt the sedimentary bedding?

A)biochemical precipitation
B)cementation
C)bioturbation
D)cross-bedding

Answer 1

C

Question 2

In which of the following environments are siliceous sediments deposited?

A)deep-sea
B)reef
C)evaporite
D)swamp

Answer 2

A

Question 3

What is the porosity of newly deposited mud?

A)less than 5%
B)between 5% and 20%
C)between 20% and 50%
D)greater than 50%

Answer 3

D

Question 4

The salinity of the ocean

A)increases by approximately 1% each year.
B)remains approximately constant.
C)decreases by approximately 1% each year.
D)fluctuates by up to 10% depending on the annual rainfall.

Question 5

What type of sediments are accumulations of solid fragments produced by weathering?

A)biochemical sediments
B)clastic sediments
C)chemical sediments
D)all of the above

Question 6

Which of the following processes occurs during lithification?

A)recrystallization of unstable minerals
B)compaction
C)cementation
D)All of these may occur during lithification.

Question 7

How fast are moderate-strength river currents that carry and deposit sand?

A)2 to 5 cm/s
B)5 to 20 cm/s
C)20 to 50 cm/s
D)50 to 200 cm/s

Question 8

Which of the following environments is an example of a shoreline environment?

A)alluvial
B)continental shelf
C)delta
D)organic reef

Question 9

Which of the following sets of processes is written in order of increasing temperature?

A)sedimentation,metamorphism,diagenesis
B)diagenesis,sedimentation,metamorphism
C)sedimentation,diagenesis,metamorphism
D)metamorphism,diagenesis,sedimentation

Question 10

Which of the following terms describes the alteration of sediments to sedimentary rocks after deposition?

A)diagenesis
B)crystallization
C)precipitation
D)metamorphism

Question 11

What is the approximate temperature of sediment that is buried to a depth of 4 km?

A)0°C
B)120°C
C)200°C
D)250°C

Question 12

In what type of environment did the ripples depicted below most likely form?

A)beach (waves)
B)alluvial (stream)
C)desert (wind)
D)delta (river plus tides)

Question 13

Which of the following statements about transportation of sediment is false?

A)Smaller particles settle faster than larger particles.
B)As a current slows,the largest particles start to settle.
C)Faster currents carry larger particles than slower currents.
D)Rivers and ocean currents move much more material than do air currents.

Question 14

Burial of sediments results in

A)decreasing pressure and decreasing temperature.
B)decreasing pressure and increasing temperature.
C)increasing pressure and decreasing temperature.
D)increasing pressure and increasing temperature.

Question 15

The tendency for variations in current velocity to segregate sediments on the basis of particle size is called

A)compaction.
B)lithification.
C)metamorphism.
D)sorting.

Question 16

In which of the following environments would gravel least likely be deposited?

A)alluvial
B)beach
C)deep-sea
D)glacial

Question 17

Which of the following minerals would be most concentrated at a site containing heavily weathered sediments?

A)amphibole
B)feldspar
C)mica
D)quartz

Question 18

In which of the following sedimentary environments would gravel most likely be deposited?

A)alluvial
B)continental shelf
C)deep-sea
D)deltaic

Question 19

Which of the following is not a sedimentary structure?

A)bioturbation
B)cross-bedding
C)vesicles
D)ripples

Question 20

Which of the following sedimentary environments is dominated by river currents and waves?

A)alluvial
B)deep-sea
C)deltaic
D)desert

Question 21

Which of the following lists is written in order of decreasing particle size?

A)conglomerate,sandstone,siltstone
B)sandstone,siltstone,conglomerate
C)sandstone,conglomerate,siltstone
D)siltstone,sandstone,conglomerate

Question 22

Which of the following minerals does not precipitate directly from seawater?

A)calcite
B)dolomite
C)gypsum
D)halite

Question 23

The most abundant chemical/biochemical sedimentary rocks are

A)carbonates.
B)cherts.
C)sandstones.
D)shales.

Question 24

Which of the following minerals is least likely to occur in a marine evaporite environment?

A)borates
B)gypsum
C)halite
D)quartz

Question 25

A clastic sedimentary rock composed of medium-grained (1-mm diameter)particles is called a

A)conglomerate.
B)sandstone.
C)shale.
D)siltstone.

Question 26

Most of the carbonate sediments of the ocean are derived from

A)coral.
B)crustaceans.
C)fish.
D)foraminifera.

Question 27

Where do atolls form?

A)on beaches along active continental margins
B)on subsiding volcanic islands
C)on tidal flats in humid environments
D)on wave-dominated deltas

Question 28

In which of the following sedimentary rocks would it be easiest to determine the type of rocks from which the sediment was derived?

A)conglomerates
B)sandstones
C)shales
D)siltstones

Question 29

The Bahamas are an example of a(n)

A)alluvial environment.
B)carbonate platform.
C)deltaic deposit.
D)rift valley.

Question 30

Which of the following is an example of a clastic sedimentary rock?

A)chert
B)dolostone
C)evaporite
D)shale

Question 31

What is the most abundant nonclastic sediment?

A)carbonate
B)chert
C)coal
D)halite

Question 32

Which of the following is deposited only by nonbiological,chemical precipitation?

A)chert
B)coal
C)halite
D)limestone

Question 33

Which of the following rocks is composed of clay-sized clastic sediment?

A)conglomerate
B)dolostone
C)sandstone
D)shale

Question 34

Which of the following statements is true?

A)Cementation and compaction both decrease porosity.
B)Cementation increases porosity,whereas compaction decreases porosity.
C)Cementation decreases porosity,whereas compaction increases porosity.
D)Cementation and compaction both increase porosity.

Question 35

Which of the following types of sandstones is most likely to form by the rapid mechanical weathering of a granite?

A)arkose
B)graywacke
C)quartz arenite
D)shale

Question 36

Which of the following fine-grained sedimentary rocks is clastic and displays blocky fracture and little or no bedding?

A)chert
B)coal
C)mudstone
D)shale

Question 37

The conversion of limestone to dolostone involves the replacement of calcium ions with

A)carbonate ions.
B)magnesium ions.
C)silica ions.
D)sodium ions.

Question 38

What type of sandstone contains abundant rock fragments?

A)arkose
B)graywacke
C)lithic sandstone
D)quartz arenite

Question 39

Which of the following kinds of sandstone is the most poorly sorted?

A)arkose
B)greywacke
C)lithic sandstone
D)quartz arenite

Question 40

Which of the following sedimentary rock groups are most abundant?

A)cherts and evaporites
B)sandstones and conglomerates
C)limestones and dolostones
D)siltstones,mudstones,and shales

Question 41

Physical weathering involves the breakdown of rocks at the Earth's surface through

A)chemical reactions.
B)diagenesis.
C)erosion.
D)mechanical processes.

Question 42

Oil and gas are found mainly in

A)chert and gypsum.
B)quartzite and dolomite.
C)mudstone and siltstone.
D)sandstone and limestone.

Question 43

Which of the following types of sedimentary basins is most likely to develop where two plates pull apart?

A)flexural basins
B)rift basins
C)thermal sag basins
D)All of the above are equally likely to develop.

Question 44

The type of weathering whereby rocks may be dissolved is called

A)chemical weathering.
B)mechanical weathering.
C)physical weathering.
D)diagenetic weathering.

Question 45

The three main types of sediment are

A)siliciclastic,biological,chemical.
B)bioclastic,chemical,granitic.
C)clastic,fossiliferous,bioclastic.
D)siliciclastic,erosional,ionic.

Question 46

A clastic sedimentary rock contains pieces of coarse-grained quartz.What rock is most likely in the source?

A)rhyolite
B)andesite
C)granite
D)gabbro

Question 47

A clastic sedimentary rock contains pieces of olivine.What rock is most likely in the source?

A)granite
B)rhyolite
C)andesite
D)basalt

Question 48

Two common types of cements in sedimentary rocks are

A)calcium and chert.
B)quartz and chert.
C)quartz and silica.
D)calcite and quartz.

Question 49

Which of the following minerals precipitates directly from water in evaporite deposits?

A)dolomite
B)feldspar
C)gypsum
D)quartz

Question 50

The type of sedimentary basin that forms as a result of one tectonic plate overriding another,causing the plate to bend downward,is called a

A)thermal subsidence basin.
B)tectonic basin.
C)rift basin.
D)flexural basin.

Question 51

Sedimentary processes take place

A)within Earth's interior.
B)within Earth's atmosphere.
C)at or near Earth's surface.
D)within Earth's interior or atmosphere,or near Earth's surface.

Question 52

Coral reefs are generally limited to waters approximately ________ deep or less.

A)5 m
B)20 m
C)100 m
D)20 km

Question 53

At what temperature does organic matter begin to convert to oil and gas?

A)90°C
B)50°C
C)190°C
D)150°C

Question 54

Which of the following processes is not an important cause of subsidence during the development of a sedimentary basin?

A)cooling and contraction of the crust
B)erosion of sediments
C)deposition of sediments
D)tectonic downfaulting

Question 55

Which of the following sedimentary rocks is composed of biochemically precipitated silica?

A)chert
B)evaporite
C)limestone
D)quartz arenite

Question 56

If coins represent sediment grains,then which of the following collections of coins would be best sorted?

A)5 pennies and 5 quarters
B)5 pennies,5 dimes,and 5 quarters
C)8 pennies and 2 quarters
D)10 pennies

Question 57

The study of sedimentary rocks helps geoscientists determine

A)ancient ocean environments.
B)former plate tectonic events.
C)history of climate change.D)ancient ocean environments,former plate tectonic events,and history of climate change.

Question 58

A sediment composed of roughly equal amounts of quartz and feldspar grains is transported over a long distance.What will the sediment end up looking like?

A)well-sorted and rounded grains consisting of mostly of feldspar
B)well-sorted and rounded grains consisting mostly of quartz
C)well-sorted and rounded grains consisting entirely of felspar
D)well-sorted and rounded grains consisting entirely of quartz

Question 59

Sedimentary basins are formed by a process called

A)diagenesis.
B)subduction.
C)subsidence.
D)lithification.

Question 60

Coal is produced from the diagenesis of

A)foraminifera.
B)swamp vegetation.
C)dinosaur bones.
D)algae.

Question 61

Turbidites are sedimentary deposits that are characterized by

A)ripple marks.
B)cross-bedding.
C)graded bedding.
D)poor sorting.

Question 62

Which of the following sedimentary rocks' formation does not involve a primary sediment?

A)mudstone
B)conglomerate
C)dolostone
D)sandstone

Question 63

Sedimentary particles that are abraded will become

A)smaller and more angular.
B)smaller and more rounded.
C)larger and heavier.
D)larger and more angular.

Question 64

If a sediment started out with equal proportion of quartz and feldspar,then which of the following sediment compositions will have been transported the furthest?

A)quartz/feldspar = 1
B)quartz/feldspar = 1/2
C)quartz/feldspar = 2/1
D)quartz/feldspar = 3/1

Question 65

Which sedimentary rock is makes up flint?

A)sandstone
B)limestone
C)gypsum
D)chert

Question 66

The major environments for sedimentary deposition are often grouped into

A)land and sea.
B)terrestrial and marine.
C)continental,shoreline,and marine.
D)continental,transitional,and marine.

Question 67

Which of the following sedimentary structures suggests the presence of a back-and-forth current?

A)asymmetric ripple marks
B)cross-bedding
C)graded bedding
D)symmetric ripple marks

Question 68

A sedimentary environment contains sand,mud,and gravel and shows little biological activity.Which of the following environments fits this description best?

A)desert
B)glacial
C)lake
D)continental slope

Question 69

As seawater evaporates the following sequence of minerals/compounds forms (in the order of first to last):

A)halite,gypsum,carbonates,Mg- and K-chlorides.
B)gypsum,carbonates,halite,Mg- and K-chlorides.
C)Mg- and K-chlorides,halite,gypsum,carbonates.
D)carbonates,gypsum,halite,Mg- and K-chlorides.

Question 70

Which of the following sedimentary rocks would be classified as biochemical?

A)shale
B)siltstone
C)sandstone
D)coal

Question 71

Today reefs constructed mostly by corals.Which organisms made reefs before corals?

A)forams
B)rudists
C)oysters
D)armoured fish

Question 72

Which of the following is not a clastic sedimentary environment?

A)alluvial
B)beach
C)delta
D)evaporate

Question 73

Research suggests that bulk seawater chemistry has not changed much over the last 1.8 billion years.This observation is supported by the study of what kind of sedimentary rock?

A)sandstone
B)limestone
C)chert
D)evaporites

Question 74

Research on marine evaporates indicates that bulk seawater chemistry has not changed much over approximately the last _______ years?

A)2 million
B)100,000
C)2 billion
D)4)6 billion

Question 75

What sort of sedimentary environments are floodplains?

A)desert
B)glacial
C)lake
D)alluvial

Question 76

Which of the following sediment sequences shows increasing grain size (left to right)?

A)sand,silt,clay
B)silt,sand,mud
C)mud,sand,pebble
D)gravel,sand,silt