Midterm Rev

Question 1

List 3 basic types of Sedimentary Rock

Answer 1

Siliciclastic
Biochemical/chemical
carbonaceous

Question 2

What are the 3 main features to look for when identifying a paleosol?

Answer 2

root traces
soil horizons
soil structures

Question 3

List 2 assumptions made when using a Hjulstrom Diagram

Answer 3

Spherical quartz grain
1m depth
(write more here)

Question 4

What are the 4 common dispersive in sediment gravity flows

Answer 4

turbidity
cohesiveness
grain to grain interactions
liquification
(check this answer)

Question 5

what is a cutan

Answer 5

clay skin that surrounds peds within soils

Question 6

does a debris flow generally produce a matrix or clast supported conglomerate

Answer 6

matrix supported conglomerate

Question 7

which form of bedload transport is characterized by the movement of a grain that is in constant contact with the bed (sliding, rolling, etc.)

Answer 7

traction

Question 8

According to the Udden Wentworth scale, what size class would a grain 12 microns diameter belong to

Answer 8

silt

Question 9

how are groove casts created and where do we find them (what part of the bed)

Answer 9

-an object impacts the bed and is dragged along creating a groove, then a cast is made of this
-groove casts are found on the bottom of the bed

Question 10

what is the best method for quantifying grain shape

Answer 10

fourier transform analysis

Question 11

Put the following bedforms in order from lowest to highest energy regime: antidunes, dunes, ripples, and planar bedding

Answer 11

ripples, dunes, planar bedding, antidunes

Question 12

what is flaser bedding

Answer 12

ripple cross laminations are filled with mostly sand and some mud (depositional structure)
-(my answer: more sand than mud; mud ripples preserved in sand)

Question 13

what bedforms produce tabular cross bedding

Answer 13

straight crested dune

Question 14

what is an ichnofacies

Answer 14

assemblage of ichnofossils that tell you about the environment they were formed in

Question 15

what is the difference between a thrombolite and a stromatolite (be specific as to which one has said properties)

Answer 15

-stromatolite: has internal structure and has laminations
-thombolite: has no internal structure and has no laminations

Question 16

what is the most common cement in sandstones

Answer 16

silica

Question 17

what is a styolite (include the rock type they commonly form in)

Answer 17

styolites are a dark colored accumulation as a result of diagenisis in limestone/carbonates
(check this)

Question 18

what is the most common accessory mineral within sandstones?

Answer 18

mica

Question 19

give an example of a common stable heavy mineral in sandstones

Answer 19

rutile, zircon, titanite

Question 20

what is an arkose

Answer 20

arkose = greater than 25% feldspar in a sandstone

Question 21

give the classification of a clastic rock composed of 75% sand sized grains with the framework grains compimised of 65% qtz 12% feldspar and 23% rock fragments

Answer 21

lithic wacke

Question 22

would a quartz arenite with well rounded grains be considered mature or immature

Answer 22

mature

Question 23

what is provenance in relationship to sandstones

Answer 23

source of the grains

Question 24

during diagenesis smectite is often converted to what clay mineral

Answer 24

illite

Question 25

what is the difference between a shale and mudstone

Answer 25

shale is fissle
mudstone is not fissile

Question 26

what are the 3 main components of carbonate rocks (e.g. think of their texture)

Answer 26

-allochems
-microcrystalline calcite
-sparry calcite

Question 27

what are the 4 main minerals comprising carbonate rocks?

Answer 27

-high Mg calcite
-low Mg calcite
-aragonite
-dolomite

Question 28

according to dunham classification, what type of limestone is grain-supported rock, lacking lime mud whose allochems are all less than 2mm in size

Answer 28

grainstone

Question 29

what are the 3 main textures of gypsum

Answer 29

-laminated
-nodular
-massive

Question 30

what would happen to a foraminifera test(shell) that sank below the calcium carbonate compensation depth

Answer 30

it will dissolve