First Meeting PPT Flashcards
the structural attributes of bedding attitude
bed, bedding plane, dip, azimuth, strike, talus
angle of the plane of structure, horizontal; angle of inclination of the feature or structure
dip
has a perpendicular relationship
with the strike and dip
azimuth
direction of the line of the vertical
projection of the feature to the horizontal plane
strike
sediment accumulated to the base
of the slope
talus
what are the difference between azimuthal and strike reading?
azimuthal reading has 360° angular direction; strike reading has angular measurements (quadrants)
attributes of beds on aerial photographs
1) beds appear as linear feature
2) occur in a form of a group of persistent linear ridges
3) follow parallelism
4) abrupt termination is indicative of a fault
in photo-interpretation, beds can be classified through the basis of:
dip amount
beds can be classified into three groups which are:
- Horizontal and dipping beds
- Medium dipping beds
- Steep and vertical dipping beds
in the photographic attributes of horizontal beds, beds are distinguished by:
tonal contrast and different resistance to erosion
in horizontal beds, the bands are parallel to what?
topographic contours
the function of how susceptible rocks will erode
elevation
what is the general drainage pattern in horizontal beds?
dendritic
horizontal beds can be observed unless obliterated by?
talus
T or F: Contour line is the term used in describing beds in aerial photo-interpretation
False. Bedding plane.
in medium-dipping beds, bedding is expressed by bands of differing _________________________ in slope due to the resistance of beds
photographic tone or topographic breaks
what causes the abrupt change is slope angle in medium-dipping beds?
breaks in slope
T or F: Resistant beds are thicker than less-resistant beds.
False. Resistant beds appear thin as compared to less-resistant beds.
why does resistant beds have thinner bands and less
resistant beds having wider bands
due to angle of repose (caused by change in dip angles and differential weathering/erosion)
what does the medium-dipping beds allow to determine?
dip amount, dip direction, and the strike of the beds
an asymmetric ridge
dip-slope or Cuesta
the longer, gentle slope in a cuesta
face slope
the steeper part of a cuesta
steep slope
may be applied to determine the direction of the dip where a
stream valley intersects the trace of a bed
Rule of ‘V’
the ‘V’ in the outcrop pattern will point to the:
direction of the dip
T or F: Less-resistant beds has advanced erosion.
True
the relationship between the size of the outcrop pattern and the dip magnitude
inversely proportional
if the outcrop pattern is small and narrow, what is its corresponding dip angle?
higher dip angle
what do you call the diagnostic landscape of a steeply-dipping bed that has sharp, straight or slightly curved ridges with same high dipping opposing slopes
hogback
steeply-dipping beds are often covered by talus in which side of a hogback ridge?
both sides
T or F: in steeply-dipping beds, the long axis is proportional to the strike of the bedding.
False. the long axis is PARALLEL to the strike of the bedding
T or F: The true thickness of a vertical or nearly vertical bed is difficult to measure in steeply-dipping beds
False. It can be easily measured.
what are the criteria to determine the direction of the dip?
Rule of ‘V’, Drainage characteristics
In the ‘V’ Rule, which part of the V always points to the dip
direction?
the apex of V
The long and narrow V shape shows
less dip amount or gently sloping beds
Short and wide V shape refers to
medium and steep dipping beds
T or F: Dips could be gentle, if the relatively long
tributary systems commonly flow down the
face slopes.
True
what does short tributary streams characterize?
back slopes
high drainage density corresponds to ____________
steep dip
the amount of channels in a given unit area. it is a function of how much time water has to accumulate in a channel.
drainage density
in drainage characteristics, gentler slopes mean
less drainage density
form zig-zag shape or ‘V’ shape pattern on aerial photograph
folds
A plunging anticline forms a V-shaped outcrop pattern with the apex (or nose) pointing to which direction?
direction of the plunge
T or F: Does plunging synclines form a similar pattern?
True. Plunging synclines form a similar pattern.
limbs opening at the direction of the plunge
syncline
roughly circular to elliptical outcrop, where beds dipping away form a central area.
Dome
T or F: Eroded dome is made up of the youngest bed at the center with older rock units located outward.
False. Oldest beds are at the center, while younger rock units are located outward.
Dome forms which drainage pattern?
Radial pattern
If the structure has been dissected by ______________, the V in the outcrop points __________ from the center of a basin.
stream erosion; outward
elliptical or circular outcrop pattern; beds dip toward the central area
basin
T or F: In basin-shaped structures, the youngest strata are located at the center.
True
If the structure has been dissected by _____________, the V in the outcrop points __________ the center of a basin.
stream erosion; toward
appear as lines or zones or displacement that abruptly offset
structures and terminate contracts between formations
fault patterns
generally dip at a low angle and appear as a zig-zag irregular trace
thrust fault
