Chapter 6

Question 1

sediment

Answer 1

loose mineral grains such as clasts, shells and shell fragments, plant debris, and or mineral crystals precipitated from bodies of water

Question 2

clasts

Answer 2

fragments or grains produced by weathering of a rock - boulders, pebbles, sand, silt

Question 3

Sedimentary rock

Answer 3

forms at or near the Earth’s surface by the cementation and compaction of accumulated layers of different kinds of sediments

Question 4

Weathering

Answer 4

the chemical and/or physical breakdown of preexisting rock

Question 5

Weathering produces both

Answer 5

clasts and dissolved ions

Question 6

dissolved ions

Answer 6

charged atoms or molecules in a water solution

Question 7

cement

Answer 7

when ions precipitate from ground-water in the spaces between clasts forming cement which holds the clasts together

Question 8

Physical weathering

Answer 8

breaks the rock into fragments but does not change the minerals that make up the rock

Question 9

Chemical weathering

Answer 9

process which rock chemically reacts with air, water, and acidic solutions
involves chemical reactions
Generally reduces the number of minerals in sediments over time

Question 10

chemical reactions

Answer 10

the breaking and forming of chemical bonds

can produce new minerals

Question 11

unstable or nonresistant minreals

Answer 11

minerals that are easily weathered

Question 12

stable or resistant minerals

Answer 12

those that can survive weathering

Question 13

mineralogically immature

Answer 13

sediments that contain minerals which are susceptible to chemical weathering (unstable)

Question 14

mineralogically mature

Answer 14

stable

sediments that contain minerals which are resistant to weathering

Question 15

classes of rocks

Answer 15

clasts
chemical
biochemical
organic

Question 16

Clastic sedimentary rocks

Answer 16

formed from clasts
texture in which discrete grains are held together by a chemical cement or very fined-grained clastic matrix
majority are silicate rocks

Question 17

weathering of clasts

Answer 17

reduces bedrock into a pile of loose (separate mineral) grains or loose clasts also known as detritus

Question 18

Erosion of clasts

Answer 18

water, air, glaciers

Question 19

lithification of clasts

Answer 19

loose sediment into solid rock through compaction and cementation

Question 20

compaction

Answer 20

when weight of an overlaying sediment squeezes out air or water pressing the clasts closer together

Question 21

diagenesis

Answer 21

application of pressure and the circulation of fluids overtime gradually change characteristics of sediments and sedimentary rock

Question 22

Chemical sedimentary rocks

Answer 22

form when water ions become oversaturated and excess ions bond together to form solid mineral grains

Question 23

cryptocrystalline rocks

Answer 23

grains are so small they look like porcelain

Question 24

Evaporites

Answer 24

chemical sedimentary rocks in thick deposits composed of crystals formed when salt water evaporates

Question 25

Travertine

Answer 25

rocks composed of crystalline calcium carbonate formed from groundwater from hot or cold water springs or caves

Question 26

Biochemical sedimentary rocks

Answer 26

consist primarily of the remains of once-living organisms

Question 27

Organic sedimentary rocks

Answer 27

contain significant qualities of of the organic material from the soft, carbon rich parts of those organisms

Question 28

sorting

Answer 28

measure of the uniformity of grain size

Question 29

subrounded

Answer 29

smooth edges and corners

Question 30

sediment maturity

Answer 30

degree to which a sediment has evolved from a crushed-up version of the original rock into a sediment that has lost its easily weathered minerals and become well sorted and rounded

Question 31

beds

Answer 31

layers of sediments

Question 32

graded beds

Answer 32

layers in which the grain size decreases progressively from the bottom to the top

Question 33

asymmetric ripple marks

Answer 33

current that flowed from the gentle side toward the steep side

Question 34

symmetric ripple marks

Answer 34

have steep slopes on both sides from oscillating currents