Deck 6: Sedimentation: Rocks Formed by Surface Processes

Question 1

Abrasion of sediment particles results in which of the following?

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

Answer 1

B

Question 2

In what type of rocks are you most likely to find oil, natural gas, and coal?

A) igneous
B) metamorphic
C) sedimentary

Answer 2

C

Question 3

The pressure on sediment that is buried to a depth of 4 km is approximately ___ times atmospheric pressure.

A) 10
B) 100
C) 1000

Answer 3

C

Question 4

Most shells of marine organisms are composed of

A) calcium carbonate.
B) calcium phosphate.
C) silica.

Question 5

Which of the following is a common product of the weathering of silicate rocks?

A) feldspar
B) pyroxene
C) clay minerals
D) amphibole

Question 6

Which kind(s) of sediment accumulate(s) where transport currents are strong?

A) gravel
B) mud
C) both gravel and mud

Question 7

Clastic sediments are much more abundant in Earth's crust than are chemical and biological sediments.

Question 8

In a desert environment, the primary transport agent is/are

A) lake currents
B) river currents
C) wind

Question 9

Which of the following geologic processes causes the subsidence observed in newly forming rift valleys?

A) thermal subsidence
B) compressive flexure
C) crustal thickening
D) lithosphere thinning

Question 10

The thick accumulations of sediment on the North American Atlantic margin are the result of which geologic process?

A) thermal subsidence
B) rift-basin formation
C) convergent boundary tectonic flexure
D) convergent boundary volcanism

Question 11

Assuming the sand dune was deposited by wind currents, which way was the wind blowing?

A)

B)

C)

D) Cannot determine from the information given.

Question 12

The diagonal layers are called ________.

A) cross-beds
B) graded beds
C) point bars
D) ripples

Question 13

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

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

Question 14

-In which of the following sedimentary environments would you be most likely to find symmetrical ripples?

A) alluvial
B) beach
C) desert

Question 15

Bioturbation structures in sedimentary rock are evidence of

A) burrowing marine organisms.
B) back and forth movement of water waves.
C) sediment deposited by wind.

Question 16

Graded bedding is a common sedimentary structure in which environment?

A) lakes
B) continental slopes
C) deserts

Question 17

Which of the following sedimentary environments is not characteristically a siliciclastic sedimentary environment?

A) A glacial environment
B) A desert environment
C) A coral reef environment
D) A beach environment

Question 18

Chemical sedimentary environments are found only in marine settings.

Question 19

During diagenesis the sediments may undergo ___ changes.

A) physical
B) chemical
C) both physical and chemical

Question 20

Compaction reduces both the volume and porosity of buried sediments, whereas cementation reduces the porosity of sediments and leaves the volume unchanged.

Question 21

Which of the following rocks is composed of calcium carbonate?

A) chert
B) dolostone
C) limestone

Question 22

Coal is best classified as a(n) ___ sedimentary rock.

A) chemical
B) clastic
C) organic

Question 23

Which of the following substances is made up of silica?

A) chert
B) dolostone
C) phosphorite

Question 24

Which of the following evaporite minerals forms first in a marine evaporite environment?

A) gypsum
B) potassium chlorite
C) halite

Question 25

Which of the following is considered a carbonate mineral?

A) gypsum
B) opal
C) chalcedony
D) aragonite

Question 26

Which of the minerals listed is characteristic of phosphorites?

A) hematite
B) dolomite
C) calcite
D) apatite

Question 27

Which kind of rock listed below forms from a siliceous sediment?

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

Question 28

Which kind of rock forms almost entirely from the diagenesis of swamp vegetation?

A) chert
B) gypsum
C) coal
D) all of these

Question 29

Chemical sediments are more abundant than biological sediments.

Question 30

Studies of marine evaporate deposits indicate that the chemistry of ocean water has changed greatly over the past 1.8 billion years.