Question 1

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

Accepted Answer

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

Question 2

The thickest sequences of sedimentary rocks are typically found in ____________.

Accepted Answer

A)   the oceans, beside the mid-ocean ridges
B)   the interior of the largest continents
C)   sedimentary basins, broad depressions that catch sediment
D)   mountain belts, broad areas where rock and sediment are uplifted C

Question 3

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

Accepted Answer

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 C

Question 4

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

Accepted Answer

A)   ice
B)   water
C)   wind

Question 5

Of the grains above,which possesses greater sphericity?

Accepted Answer

A)   grain A
B)   grain B
C)   Neither, both grains possess approximately equal sphericity.

Question 6

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

Accepted Answer

A)   in a river bed
B)   by a glacier
C)   on a beach
D)   in an alluvial fan

Question 7

A sandstone with a large proportion of feldspar due to the physical weathering of granite is more precisely termed a(n)____________.

Accepted Answer

A)   arkose
B)   breccia
C)   greywacke
D)   wacke

Question 8

The difference between breccia and conglomerate is that conglomerate ___________.

Accepted Answer

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 9

Unlike physically precipitated chert,biochemical chert ____________.

Accepted Answer

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

Question 10

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

Accepted Answer

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 11

The smallest detrital grains are ____________.

Accepted Answer

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

Question 12

As compared with metamorphism,diagenesis ____________.

Accepted Answer

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 13

Geologically,medium-sized sediment refers to ____________.

Accepted Answer

A)   cobbles
B)   pebbles
C)   sand
D)   silt

Question 14

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

Accepted Answer

A)   deposition
B)   erosion
C)   weathering

Question 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

Which type of sediment settles at greater fluid velocities than sand?

Accepted Answer

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

Question 18

Grains become rounded primarily during ____________.

Accepted Answer

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

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

A)   regressions
B)   transgressions
C)   divarications

Exam 6: Pages of Earths Past: Sedimentary Rocks