Sedimentary Rocks Chapter 7

Front 1

How does the volume of sedimentary rocks in earth's crust compare to the volume of igneous and metamorphic rocks?

Back 1

Most of the earth consists of igneous and metamorphic rocks they make up 90 to 95% of the outer crust. However about 75% of the land area are covered by sedimentary rocks. Meaning sedimentary rock are only on the surface

Front 2

List two ways in which sedimentary rocks are important

Back 2

They contain fossils, and Sedimentary rocks are also the primary reservoir of groundwater

Front 3

mass wasting

Back 3

Solid particles move downslope by gravity often affected by water

Front 4

changes that take place after sediments are deposited during and after lithification

Back 4

Diagenesis

Front 5

Rocks that form from the accumulation of materials that originate and are transported as solid particles from weathering

Back 5

detrital sedimentary rocks

Front 6

Chemical sedimentary rocks

Back 6

rocks that form by precipitation of minerals from water by either organic or inorganic means

Front 7

when dissolved materials come out of water. For example: Take a glass of water and pour some salt (halite) into it. The salt will dissolve into the water.

Back 7

Precipitation

Front 8

Organic sedimentary rocks

Back 8

form from the accumulation and lithification of organic debris, such as leaves, roots, and other plant or animal material.

OR

Sedimentary rock composed of organic carbon from the remains of plants that died and accumulated on the floor of a swamp. Coal is the primary example.

Front 9

List three basic sedimentary rock categories

Back 9

Organic, detrital, and chemical sedimentary rocks

Front 10

What minerals are most abundant in detrital sedimentary rocks

Back 10

Clay minerals (feldspar) and quartz

Front 11

detritus

Back 11

Loose particles or grains formed by the disintegration of rocks

Front 12

What is the primary basis for distinguishing detrital rocks

Back 12

particle size

Front 13

The formation of sedimentary rock requires

Back 13

weathering and erosion of pre-existing rocks

Front 14

sedimentary rock composed of solid masses of intergrown crystals

Back 14

rock salt

Front 15

You find a sedimentary rock that has all its flat particles aligned in parallel. From this you can infer that _____

Back 15

The particles have been compacted

Front 16

flat particles are aligned parallel in a sedimentary rock are

Back 16

compacted

Front 17

compaction

Back 17

A type of lithification in which the weight of an overlaying material compresses more deeply buried sediment

Front 18

cementation

Back 18

A type of lithification. As percolating water coats the water with mineral matter, and gradually cements the particles together

Front 19

Name the 2 types of lithification

Back 19

compaction and cementation

Front 20

A fine grained sedimentary rock consisting of silt and clay size particles

Back 20

Shale

Front 21

Name the 5 types of detrital rocks

Back 21

conglomerate, breccia, sandstone, shale, mudstone, and siltstone

Front 22

As silt and clay accumulate they tend to form thin layer called what

Back 22

laminae

Front 23

Fissility

Back 23

capable of being split or divided; cleavable (often refers to shale)

Front 24

mudstone

Back 24

a dark sedimentary rock formed from consolidated mud and lacking the laminations of shale.

Front 25

siltstone

Back 25

fine-grained sedimentary rock consisting of consolidated silt

Front 26

the most common sedimentary rock

Back 26

shale

Front 27

Sandstone

Back 27

Sedimentary rock in which sand size grains predominate (after shale sandstone is the most abundant sedimentary rock)

Front 28

Sorting

Back 28

Refers to the degree of similarity in particle size in a sedimentary rock

Front 29

Sedimentary rocks that exhibit the intergrowth of crystal masses are generally formed from the products of ___

Back 29

chemical weathering (Chemical weathering produces extremely small particles that can later precipitate to produce intergrown crystal masses.)

Front 30

If all the particles in a detrital sedimentary rock are nearly the same size, it is _______

Back 30

very well sorted

Front 31

A smooth grain shaped like a cigar is __________ and shows _________

Back 31

well-rounded; low sphericity

Front 32

Wind-blown sand deposits would most likely be __________ and __________.

Back 32

very well-sorted; well-rounded

Front 33

what correlate to transport distance

Back 33

grain size and rounding

Front 34

A conglomerate is poorly sorted with well-rounded grains. This rock was likely formed in what depositional environment

Back 34

mountain stream

Front 35

What is the most abundant chemical sedimentary rock in Earth’s crust?

Back 35

limestone

Front 36

Working in the field, you find a rock that contains rounded fragments that are greater than 2 mm in diameter. What would you call this rock

Back 36

conglomerate

Front 37

The geologic laboratory where you work received a sample for analysis that is composed of calcite that includes many microscopic fossils of marine organisms and reacts with acid. What name would identify this rock?

Back 37

chalk (Chalk is a biochemical sedimentary rock composed of calcite and contains many microscopic fossils of marine organisms.)

Front 38

Name the progression of coal types with increased heat and pressure from burial

Back 38

peat, lignite, bituminous, anthracite

Front 39

Abundant plant material accumulating in a swampy environment with __________ is required for peat to form.

Back 39

low oxygen levels

Front 40

What coal is soft, black in color, and produces soot upon handling

Back 40

bituminous

Front 41

How is anthracite produced from bituminous coal

Back 41

metamorphism

Front 42

In the United States, the most common type of coal is __________ and the largest producing state is __________.

Back 42

sub-bituminous; Wyoming

Front 43

The common sediment name for particles bigger than 2mm are called

Back 43

gravel

Front 44

conglomerate

Back 44

a coarse-grained sedimentary rock composed of rounded fragments (> 2 mm) within a matrix of finer grained material.

Front 45

breccia

Back 45

rock consisting of angular fragments cemented together

Front 46

arkose

Back 46

Sandstone containing 25% or more feldspar

Front 47

name the 3 types of sandstone

Back 47

Arkose, quartz sandstone, and graywacke

Front 48

graywacke

Back 48

sandstone containing both quartz and feldspar and is dark colored (abundant rock fragments)

Front 49

Turbidity currents

Back 49

an underwater current flowing swiftly downslope owing to the weight of sediment it carries.

Front 50

biochemical sedimentary rocks

Back 50

consist of fragments of particles produced by precipitation from once living organisms. Most of these rocks are limestones and cherts

Front 51

coquina

Back 51

a cooars rock composed of poorly cemented shells and ssh fragments

Front 52

chalk

Back 52

a soft porous rock made up almost entirely of the hard parts of microscopic marine organisms

Front 53

travertine

Back 53

a type of inorganic limestone commonly seen in caves

Front 54

oolitic limestone

Back 54

a rock composed of small spherical grains (ooids)

Front 55

Ooids

Back 55

are small (2 mm in diameter), spheroidal, "coated" (layered) sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals.

Front 56

Dolostone

Back 56

Closely related to limestone, a rock composed of the calcium-magnesium carbonate mineral dolomite (doesn't react to acid [easy way to tell apart from limestone])

Front 57

Chert

Back 57

a hard, dark, very well compacted rock composed of silica and quartz with an fine-grained texture. It occurs in nodules or bedded cherts

Front 58

Name the 4 different varietys of chert

Back 58

Petrified wood, Flint, Jasper, and Agate

Front 59

Evaporites

Back 59

A sedimentary rock formed of material deposited from solution by evaporation of the water

Front 60

name two examples of evaporites

Back 60

halite and gypsum

Front 61

salt flats

Back 61

A white crust on the ground that is produced when water evaporates and leaves behind its dissolved materials.

Front 62

how do evaporites form

Back 62

from crystals that precipitate during evaporation of water (water with dissolved material in it), such as in a drying lake bed.

Front 63

Define Coal

Back 63

fossilized organic plant matter (organic)

Front 64

PEAT

Back 64

Partially altered plant material

Front 65

lignite

Back 65

soft brown coal

Front 66

bituminous

Back 66

soft black coal

Front 67

Anthracite

Back 67

Hard black coal or metamorphism of bituminous coal

Front 68

How does PEAT form

Back 68

The partial decomposition of plant remains in a an oxygen poor swamp

Front 69

Clastic texture

Back 69

A sedimentary rock texture consisting of broken fragments of preexisting rock.

Front 70

compaction

Back 70

A type of lithification in which the weight of overlying material compresses more deeply buried sediment. It is most important in the fine-grained sedimentary rocks such as shale.

Front 71

Environment of deposition

Back 71

A geographic setting where sediment accumulates. Each site is characterized by a particular combination of geologic processes and environmental conditions.

Front 72

mud crack

Back 72

A feature in some sedimentary rocks that forms when wet mud dries out, shrinks, and cracks.

Front 73

Fissility

Back 73

The property of splitting easily into thin layers along closely spaced, parallel surfaces, such as bedding planes in shale.

Front 74

graded beds

Back 74

A sedimentary layer that most characterizes rapid deposition from water containing sediment of varying sizes. Also the layer gradually changes from coarse to fine within the one layer

Front 75

nonclastic rocks

Back 75

A term for the texture of sedimentary rocks in which the minerals form a pattern of interlocking crystals.

Front 76

Bedding Plane

Back 76

A nearly flat surface that separates two beds of sedimentary rock. Each bedding plane marks the end of one deposit and the beginning of another having different characteristics.

Front 77

Facies

Back 77

A portion (layer) of a rock unit that possesses a distinctive set of characteristics that distinguishes it from other parts of the same unit.

Front 78

Ripple marks

Back 78

Small waves of sand that develop on the surface of a sediment layer by the action of moving water or air.

Front 79

cross-bedding

Back 79

A structure in which relatively thin layers are inclined at an angle to the main bedding. Cross-bedding is formed by currents of wind or water.

Front 80

talus slope

Back 80

a debris pile up on the base of a mountain

Front 81

Limestones originated as what

Back 81

coral reefs

Front 82

evaporite rock rich in halite

Back 82

Rock salt

Front 83

another name for strata is

Back 83

beds

Front 84

What property of detrital sedimentary rocks can be indicative of the energy of sediment transport

Back 84

grain size (Grain size in a detrital sedimentary rock typically indicates the amount of energy associated with the transport of the sediment. High-energy transport can move much larger grains than low-energy transport.)

Front 85

For a detrital sedimentary rock that contains mudcracks, you could be confident that the environment in which it formed was _____

Back 85

alternately wet and dry

Front 86

In your field area you find a quartz sandstone unit with cross-bedding in it that is on the order of 2 m high. In what environment would you deduce this rock formed?

Back 86

sand dunes (Quartz sandstone with 2-meter-scale cross-bedding would be typical of sand dunes)

Front 87

In another field area you find a detrital sedimentary rock that contains particles larger than 264 mm that are rounded and surrounded by finer-grained particles. In what environment might you think these sediments were deposited

Back 87

glacial moraine

Front 88

List 3 common cements

Back 88

Calcite, silica, and iron oxide

Front 89

What is the primary basis for distinguishing different chemical sedimentary rocks?

Back 89

the mineral composition

Front 90

What is the primary basis for distinguishing different detrital sedimentary rocks?

Back 90

Particle size

Front 91

All detrital rocks have what kind of texture

Back 91

clastic texture

Front 92

alluvial fan

Back 92

a fan-shaped mass of alluvium deposited as the flow of a river decreases in velocity.

Front 93

eolian

Back 93

The work of wind and its resulting deposits (named after the greek god of wind)

Front 94

playa lakes

Back 94

a lake in an arid or semiarid region that evaporates during the drier months to leave a playa

Front 95

tidal flats

Back 95

coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries.

Front 96

deltas

Back 96

An accumulation of sediment formed where a stream enters a lake or an ocean.

Front 97

spit

Back 97

An elongate ridge of sand that projects from the land into the mouth of an adjacent bay.

Front 98

barrier island

Back 98

A low, elongate ridge of sand that parallels the coast.

Front 99

What are the three broad categories of sedimentary environments

Back 99

Marine, Transitional, and Continental environments

Front 100

What consists of transitional sedimentary environments

Back 100

beaches, tidal flats, spits, bars, barrier islands, lagoons, and deltas

Front 101

What consists of continental sedimentary environments

Back 101

Streams, floodplains, alluvial fan, eolian, dunes, playa lakes

Front 102

What consists of Marine sedimentary environments

Back 102

They are divided at depth

Deep marine: all the floors of the deep ocean and sediment that deposits at the floor

Shallow Marine: Coral reefs and Skeletal debris of carbonate secreting organisms

Front 103

bedding planes

Back 103

relatively flat surfaces along which rocks tend to separate or break (often separating the strata)

Front 104

What can create bedding planes

Back 104

changes in the grain size or the composition of the sediment being deposited can create bedding planes

Front 105

What is the single most characteristic feature of sedimentary rocks

Back 105

Layers called strata or beds

Front 106

Formed when they were exposed to alternating wet and dry environments

Back 106

Mud cracks

Front 107

Describe how chemical weathering and the formation of biochemical sediment remove carbon from the atmosphere and store it in the geosphere

Back 107

Atmospheric carbon combines with water to form a weak acid—carbonic acid—that falls to the surface in rain. The acid dissolves rocks—a process called chemical weathering—and releases calcium, magnesium, potassium, sodium ions. Then gets buried in the geosphere

Front 108

Provide 3 examples by which carbon moves from the geosphere to the atmosphere

Back 108

Volcanic activity, burning and decay of biomass, and burning of fossil fuels

Front 109

list the correct sequence in the formation of a sedimentary rock?

Back 109

Weathering, erosion, deposition, lithification

Front 110

The term __________ is a collective term for all of the chemical, physical, and biological changes that take place after sediments are deposited, and during and after lithification.

Back 110

diagenesis

Front 111

What are the chief constituents in most detrital sedimentary rocks?

Back 111

Quartz and clay minerals

Front 112

what is the particle size for a Boulder

Back 112

Particle size > 256 mm

Front 113

what is the particle size for Cobble

Back 113

64–256 mm particle size range

Front 114

what is the particle size for Gravel

Back 114

Common name for sediments with particle size > 2 mm

Front 115

what is the particle size for Sand

Back 115

1/16 to 2 mm particle size range

Front 116

what is the particle size for Silt

Back 116

1/256 to 1/16 particle size range

Front 117

what is the particle size for Clay

Back 117

Particle size < 1/256 mm

Front 118

Coquina and chalk

Back 118

Biochemical limestone in which shell fragments are poorly cemented together

Front 119

Coral reef

Back 119

Formed by relatively simple invertebrate animals that secrete a calcareous skeleton and grow together

Front 120

Travertine

Back 120

Formed when groundwater droplets become exposed to the air in a cavern causing calcium carbonate concentrations to the point of precipitation

Front 121

Inorganic

Back 121

Formed when chemical changes or high water temperatures increase calcium carbonate concentrations to the point of precipitation

Front 122

Oolitic

Back 122

Composed of small spherical grains–commonly small shell fragments–coated with precipitated calcium carbonate

Front 123

Turbidity currents are generally associated with what sedimentary feature?

Back 123

Graded beds

Front 124

When a body of seawater evaporates, minerals precipitate in a certain order. What determines this order?

Back 124

Mineral solubility—less soluble minerals precipitate first; more soluble minerals precipitate later.

Front 125

Coal that has the lowest volatile content and highest percentage of fixed carbon is called _________

Back 125

Anthracite

Front 126

A diagenetic change that involves the crystallization of minerals among individual sediment grains is called _______

Back 126

cementation

Front 127

_________ is an important diagenetic process in fine-grained sediments that results in the reduction of pore space and the expulsion of water.

Back 127

Compaction

Front 128

_______ is the term that describes deposits that result from the work of wind.

Back 128

Eolian

Front 129

Compaction and cementation are examples of this process.

Back 129

lithification

Front 130

The most common minerals in detrital sedimentary rocks are __________.

Back 130

clay and quartz

Front 131

What accumulation of sediment would most likely exhibit good cross-bedding?

Back 131

windblown sand (sand dune)

Front 132

What sedimentary rock consists of materials that originated and were transported as solid particles? (sandstone or travertine limestone)

Back 132

sandstone