SEDIMENTARY PETROLOGY

Question 1

Physical destruction of the original rock

Answer 1

Mechanical Weathering

Question 2

Loose deposits are converted into rocks by the processes of __________ and __________, which include compaction and cementation of the loose materials

Answer 2

diagenesis and lithification

Question 3

Solid fragments and mineral particles from mechanical weathering

Answer 3

Detritus or clastic material

Question 4

Sediments with clastic textures

Answer 4

Terrigenous sediments

Question 5

Decomposes minerals in the rocks

Answer 5

Chemical Weathering

Question 6

Truly chemical sediments which are products of chemical decomposition

Answer 6

Orthochemical sediments

Question 7

Organisms have caused the precipitation of the major sedimentary mineral components, or the precipitated minerals have undergone substantial movement (and redeposition) after their crystallization

Answer 7

Allochemical sediments

Question 8

Example of terrigenous sedimentary rocks?

Answer 8

conglomerates, breccias, sandstone

Question 9

Examples of allochemical sedimentary rocks?

Answer 9

Limestone, dolostone, phosphorites, chert and coal

Question 10

Examples of orthochemical sedimentary rocks

Answer 10

evaporites, chert, travertine and iron formations

Question 11

Consist of detrital grains, which form the framework of the rock, and which are joined together by cement. Variable amounts of matrix, which consists of fragmental material substantially smaller than the mean size of the framework grains, may also be present

Answer 11

Terrigenous sedimentary rocks

Question 12

What is the conversion from mm to phi scale?

Answer 12

= -log2(d)

Question 13

Consists of large clasts (boulders, cobbles, pebbles, and granules) with or without a sandy matrix.

Answer 13

Conglomerates and breccias

Question 14

Show pronounced rounding of the clasts

Answer 14

conglomerates

Question 15

Contain more angular clasts.

Answer 15

breccias

Question 16

Coarse-grained pyroclastics (volcanic debris) with a grain size over 32 mm

Answer 16

Agglomerates or volcanic breccia

Question 17

Finer-grained (grain size between 2 and 0.062 mm) and most easily classified by determining the amounts of clastic (framework) grains composed of quartz (and chert), feldspar, and lithic fragments

Answer 17

Sandstone

Question 18

When the sandstone matrix constitutes more than 10 volume percent of the rock

Answer 18

wacke

Question 19

Mostly dark gray sandstones with abundant matrix

Answer 19

Greywacke

Question 20

Sandstones made up of chiefly volcanic fragments, volcanic glass, and crystals. Tend to be green because of chlorite.

Answer 20

Volcaniclastics

Question 21

General term for sediments composed mainly of silt-sized, (0.062 to 0.004 mm) and clay-sized (<0.004 mm) particles

Answer 21

mudstone

Question 22

Silt particle size

Answer 22

Siltstones

Question 23

Clay particle size; nonfissile, commonly with a massive or blocky texture

Answer 23

claystone

Question 24

Characterized by its fissility (ability to split into thin sheets), generally parallel to bedding

Answer 24

Shale

Question 25

With a well-developed cleavage, which may or may not be parallel to the bedding, and is commonly the result of metamorphism

Answer 25

Slate

Question 26

Type allochemical carbonate rocks?

Answer 26

Dolomitization

Question 27

Calcite recrystallizes easily, and secondary dolomite, replaces the original calcium carbonate; often destroys the texture of the original carbonate

Answer 27

Dolomitization

Question 28

What are the orthochemical components?

Answer 28

Microcrystalline ooze and Sparry calcite cement

Question 29

A very fine-grained carbonate precipitate that has settled to the bottom of the basin

Answer 29

Microcrystalline ooze

Question 30

Coarser in grain size than the ooze and tends to be clear or translucent; a pore-filling cement that was precipitated in place

Answer 30

Sparry calcite cement

Question 31

What are allochem components?

Answer 31

Intraclasts, Oolites, Fossils, and Pellets

Question 32

fragments of weakly consolidated carbonate sediment that have been torn up, transported, and redeposited by currents within the basin of deposition

Answer 32

Intraclasts

Question 33

in a size range of 0.1 to 1.0 mm in diameter, are spherical, show radial and concentric structures, and resemble fish roe. They are commonly formed by chemical accretion around nuclei such as shell fragments, pellets, or quartz sand grains

Answer 33

Oolites

Question 34

remains of organisms

Answer 34

Fossils

Question 35

well-rounded, homogeneous aggregates of microcrystalline calcite in a size range of 0.03 to 0.2 mm in diameter; feces of mollusks, worms, and crustaceans

Answer 35

Pellets

Question 36

consist of a matrix of allochemical constituents and sparry calcite cement

Answer 36

Type 1 of folks classification

Question 37

variable percentage of allochemical grains in a microcrystalline matrix

Answer 37

Type 2 of folks classification

Question 38

microcrystalline calcite matrix only (micrite)

Answer 38

Type 3 of folks classification

Question 39

emphasizes the depositional texture; “Were the framework grains (Folk’s allochems) in close contact with each other, that is, were they well packed when they were deposited?”

Answer 39

Dunham’s Classification of Limestones

Question 40

consists of more than 10% grains in a microcrystalline ooze (micrite)

Answer 40

Wackestone

Question 41

grain-supported limestone with micrite matrix and sparry calcite cement

Answer 41

packstone

Question 42

grain-supported limestone with very little micrite.

Answer 42

Grainstone

Question 43

equivalent to biolithite, a limestone made up of organic structures that grew in situ (in place), forming a coherent rock mass during growth

Answer 43

boundstone

Question 44

formed by direct precipitation

Answer 44

Orthochemical sedimentary rocks

Question 45

Examples of orthochemical sedimentary rocks

Answer 45

evaporites, banded iron formations, travertine