structural interpretation of aerial photographs

Question 1

6 aspects of bedding attitude

Answer 1

bed, bedding plane, dip, azimuth, strike, talus

Question 2

sedimentary stratum greater than 10mm,

lesser than 10mm?

Answer 2

> 10mm = bed
< 10mm = laminae

Question 3

surface that separates and represents the contact between two beds

Answer 3

bedding plane

Question 4

angle between the horizontal surface and the bed

Answer 4

dip

Question 5

angular distance from the magnetic north

Answer 5

azimuth

Question 6

direction of the line formed by the intersection of a planar structure and the horizontal

Answer 6

strike

Question 7

outward sloping and accumulated heap or mass of rock fragments of any size or shape (usually coarse and angular) derived from and lying at the base of a cliff or very steep, rocky slope, and formed chiefly by gravitational falling, rolling, or sliding

Answer 7

talus

Question 8

important factors to classify a pile of sediments as talus

Answer 8

-usually coarse and angular
-at the base of a cliff or very steep rocky slope
-from gravitational falling, rolling or sliding

Question 9

appear as linear features on aerial photographs

Answer 9

beds

Question 10

how do beds occur as?

Answer 10

a group of persistent linear ridges

Question 11

what orientation do beds follow?

Answer 11

parallelism

Question 12

abrupt termination of beds indicate what

Answer 12

fault

Question 13

3 groups of beds based on degree of dip

Answer 13

1. horizontal and gently dipping beds
2. medium dipping beds
3. steep and vertical dipping beds

Question 14

how are horizontal and gently dipping beds distinguished

Answer 14

by tonal contrast and different resistance to erosion

Question 15

horizontal and gently dipping bed bands are parallel to what

Answer 15

to the topographic contours with loop like shapes

Question 16

drainage pattern of horizontal and gently dipping beds

Answer 16

dendritic

Question 17

can horizontal and gently dipping beds always be observed?

Answer 17

yes until obliterated by talus

Question 18

how are bedding in medium dipping beds expressed?

Answer 18

by bands of differing photographic tone or topographic breaks in slope due to resistance of beds

Question 19

compare how resistant beds and less resistant beds appear

Answer 19

resistant beds are thinner

Question 20

what part of the attitude can you determine using beds

Answer 20

dip angle, direction and strike

Question 21

a ridge with a gently dipping slope and a steeply dipping slope

Answer 21

cuesta

Question 22

aka cuesta

Answer 22

dip-slop

Question 23

an asymmetric ridge

Answer 23

cuesta

Question 24

the longer gentler slope of a cuesta

Answer 24

face slope

Question 25

the steeper slope of a cuesta

Answer 25

steep slope lol

Question 26

what is the use of rule of V's for medium dipping beds

Answer 26

used to determine the direction of dip where a stream valley intersects the trace of a bed. the V points to the dip direction

Question 27

describe the relationship of the magnitude of the dip and the size of the outcrop in plan view

Answer 27

inversely proportional

Question 28

what is the diagnostic landscape for steeply dipping beds

Answer 28

hogback ridges

Question 29

sharp, straight or slightly curved ridges with the same high dipping opposing slopes

Answer 29

hogback

Question 30

describe the presence of talus on hogback riges

Answer 30

it's often covered with talus on both sides

Question 31

describe the long axis in hogback ridges

Answer 31

parallel to the strike of the bedding

Question 32

T or F: the true thickness of vertical or nearly vertical bed cannot be measured

Answer 32

F.

Question 33

how to tell the direction of dip (criteria)

Answer 33

1. V rule 2. Drainage characteristics

Question 34

are the V rule and drainage characteristics applicable to all surfaces

Answer 34

no, only those where the topographic surface coincides with the bedding surfaces

Question 35

explain the rule of V, and how the V's look like in steep vs gentle dips

Answer 35

- the apex of the V points to the dip direction - the V is narrower and longer in gently dipping beds (less dip angle) - the V is wider and shorter for medium and steep dipping beds

Question 36

describe the V when the slope is following the face slope

Answer 36

when the slope is following the face slope, the apex of the V points downstream (and looks thinner)

Question 37

describe the V when the slope is following the steep slope

Answer 37

when the slope is following the steep slope, the apex of the V points upstream (and looks thicker)

Question 38

how do beds cut by streams in plan view look like if the beds are vertical

Answer 38

horizontal

Question 39

what cuesta slopes are shown if the tributary system is relatively long

Answer 39

face slope (gentle)

Question 40

what cuesta slope is shown if tributary systems are short

Answer 40

back slopes (steep slopes)

Question 41

what type of slope characterize high drainage density

Answer 41

steep slopes/dips

Question 42

why is drainage density higher in steeper slopes

Answer 42

because streams are usually parallel and do not combine, compared to gentler slopes that end up joining

Question 43

form zig-zag shape of V shape patterns in aerial photos

Answer 43

folds

Question 44

appears as V shaped outcrop pattern with the apex (or nose) pointing in the direction of plunge

Answer 44

plunging anticline

Question 45

for plunging synclines, what part of the fold points to the direction of plunge

Answer 45

the opening of the limbs

Question 46

in aerial photos how can you tell if the fold is a syncline or anticline

Answer 46

based on the drainage pattern

Question 47

circular/elliptical outcrop with beds dipping away from the central area

Answer 47

dome

Question 48

when a dome is eroded, describe the relative ages of beds you can see from the center outward

Answer 48

oldest at center, progressively younger outward

Question 49

drainage pattern of domes

Answer 49

radial

Question 50

if a dome is dissected by stream erosion describe the orientation of the Vs

Answer 50

outward from center

Question 51

elliptical/circular outcrop pattern with beds dipping toward a central area

Answer 51

basin

Question 52

describe the relative ages of the beds in basins

Answer 52

younger at center

Question 53

if a dome is dissected by stream erosion, where does the V point to

Answer 53

to the center of basin

Question 54

appear as lines or zones of displacement that abruptly offset structures and terminate contacts between formations

Answer 54

fault patterns

Question 55

generally dip at low angle and appear as zigzag irregular trace

Answer 55

thrust faults