Chapter 7 - Sediments and Sedimentary Rocks

Question 1

Stratification

Answer 1

Arrangement of sediment in distinct layers (layering of rocks) (strata)

Question 2

Bedding

Answer 2

Layered arrangement of strata in a body of sediment or sedimentary rock

Question 3

Bed

Answer 3

individual layer - distinguished by differences in thickness or character

Question 4

Bedding plane

Answer 4

top or bottom surface of a bed

Question 5

Clastic Sediment

Answer 5

loose, fragmental detritus produced by mechanical breakdown of older rocks

Question 6

Clast

Answer 6

an individual particle of clastic sediment

Question 7

Poortly Sorted

Answer 7

Wide particles size range

Question 8

Well Sorted

Answer 8

Narrow size range (same size particles)

Question 9

non-sorted sediment

Answer 9

different sizes arranged chaotically - without obvious order

Question 10

rhythmic layering - Varves

Answer 10

paired lighter (nonorganic) and darker (organic) colored lake sediments

Question 11

cross bedding

Answer 11

beds inclined with respect to thicker stratum in which they occur (created from sand dunes)

Question 12

graded bedding

Answer 12

particles grade upward from coarser to finer (created from streams)

Question 13

Mineral composition

Answer 13

most coarse clastic sediments consist of those mineral grains and rock fragments least susceptible to chemical/physical breakdown (quartz is common)

Question 14

Chemical Sediment

Answer 14

formed by precipitation of minerals from solution in water

Question 15

Biogenic Sediment

Answer 15

composed mainly of fossils (remains of plants and animals)

Question 16

Bioclastic sediment

Answer 16

composed largely of fossil fragments

Question 17

Deep-sea ooze

Answer 17

Accumulation of microscopic marine organisms on sea floor

Question 18

Sedimentary Facies

Answer 18

any sediment that can be distinguished from a contemporary sediment that formed in different depositional environment

Question 19

Facies

Answer 19

The character of a rock expressed by its formation, composition, and fossil content

Question 20

Lithification

Answer 20

process whereby unconsolidated sediment is converted into rock (e.g. sand into sandstone)

Question 21

Diagenesis

Answer 21

all changes that occur after deposition and during and after lithification

Question 22

Compaction

Answer 22

weight of sediment reduces pore spaces and forces out water - fine grain rocks (e.g. mudrocks)

Question 23

Cementation

Answer 23

dissolved substances precipitate from water in pores - course grain rocks (e.g. sand and gravel into stone)

Question 24

Recrystallization

Answer 24

less stable minerals may recrystallize to more stable forms

Question 25

Chemical alteration

Answer 25

if oxygen is present organic remains conveted to CO2 and Water. if oxygen is absent organic matter transforms into mostly carbon (e.g. plants turn into coal)

Question 26

Clastic Sedimentary Rocks

Answer 26

classified on basis of predominant particle size

Question 27

Sole marks

Answer 27

collective term for features preserved on bedding surfaces

Question 28

ripple marks

Answer 28

preserved in sand that was moved by wind, streams, or waves

Question 29

mud cracks

Answer 29

polygonal markings caused by shrinking and cracking of drying mud

Question 30

trace fossils

Answer 30

footprints and trails of animals

Question 31

raindrop impressions

Answer 31

small indents left from raindrops

Question 32

color

Answer 32

may indicate if sediment was deposited in reducing (black) or oxidizing (red) environment