IV. Question (75-100) Flashcards
_______ makes plates move from spreading centers.
a) Slab pull
b) The asthenosphere
c) Ridge push
d) The lithosphere
e) nota
c) Ridge push
Ridge push is a tectonic force that drives plates away from mid-ocean ridges where new crust is formed. The elevated position of the ridge causes gravity to push the newly formed lithosphere away from the ridge axis, contributing to plate movement.
Slab pull primarily moves plates at subduction zones.
The asthenosphere is a ductile layer, but it doesn’t actively push plates.
The lithosphere itself is the rigid outer layer of the Earth.
Therefore, the correct answer is Ridge push.
Stress has ____ point components.
a) 6
b) 9
c) 3
d) 12
e) nota
b) 9
Based on the given log A, what type of fault likely caused the stratigraphy:
a. Sinistral fault
b. Dextral fault
c. Thrust fault
d. Normal fault
e. None of the above
c. Thrust fault
_______is responsible for the stratigraphy depicted in Log B
a. Sinistral fault
b. Dextral fault
c. Thrust fault
d. Normal fault
e. None of the above
c. Thrust fault
Faults are fractures with discernable amounts of _
a. flak b. emplacement c. displacement d. disgrace e. derailment
c) displacement
Boudinage structures form by _____.
a. extension b. compression c. both a & b d. neither a nor b e. nota
a) extension
In a normal fault, the _____ is down thrown.
a. foot wall b. hanging wall c. block d. fault e. nota
b) hanging wall
Explanation:
In a normal fault, the hanging wall moves downward relative to the foot wall due to extensional forces, creating a sense of separation or stretching of the crust.
The layer where magma originates is
a. crust
b. mantle
c. inner core
d. outer core
b) mantle
In simple shear, parallel lines _______ after deformation:
a. become perpendicular b. remain parallel c. are unchanged d. become unparallel e. nota
b) remain parallel
Explanation:
In simple shear, parallel lines remain parallel after deformation, although they may change orientation and length. The deformation typically involves a change in shape without a change in volume, resulting in shear strain while maintaining the parallelism of lines.
The heave is a measured on a ______ plane.
a. vertical b. horizontal c. straight d. diagonal e. nota
b) horizontal
Explanation:
Heave is the horizontal displacement component of a fault, measured perpendicular to the fault plane. It represents the amount of lateral movement between two points across the fault.
The formula for quadratic elongation λ is:
λ = 1/cos²φ
The hanging wall in a thrust fault is ______
a. hanging b. downthrown c. loose d. upthrown e. nota
d. upthrown
Unloading Joints are ___to sigma 2.
a. perpendicular b. parallel c. diagonal d. oblique e. nota
b) parallel
The formula of elongation ε is _____.
a. ε = (1/cos φ) - 1
b. 1/(cos φ - 1)
c. 1/cos φ + 1
d. 1/cos φ
e. nota
a. ε = (1/cos φ) - 1
What kind of fold is depicted in the following figure on the right?
a. True Anticline
b. True Syncline
c. Antiformal Syncline
d. Synformal Anticline
d. Synformal Anticline
“-cline” depends on the relative ages of the layers.
“–form” depends on the appearance
The formula for shear strain εᵪᵧ is _____.
a. cos φ
b. sin φ
c. cotan φ
d. a/b
e. b/a
c. cotan φ
Match the items:
- Evaporite
- Coral
- Breccia
- Peat
- Shale
- Turbidite
- Oolites
- Sand
- Gravel
- Pelagic sediment
a) Grain size is 1/16-2 mm
b) Angular clasts in finer-grained matrix
c) Particle size is >2 mm
d) They form in abyssal fans
e) Caviar-sized and shaped particles
f) Organic sediment consisting of skeletal CaCO₃
g) Deep-sea sediments without terrigenous material
h) Fine-grained sedimentary rock exhibiting fissility
i) Deposited by drying up of the river or lake bed
j) Brown, lightweight unconsolidated deposit of plant material in wet bogs
Evaporite
What is evaporite?
Evaporite is deposited by drying up of the river or lake bed. (i)
Coral
What is coral?
Coral is an organic sediment consisting of skeletal CaCO₃. (f)
Breccia
What is breccia?
Breccia consists of angular clasts in a finer-grained matrix. (b)
Peat
What is peat?
Peat is a brown, lightweight unconsolidated deposit of plant material in wet bogs. (j)
Shale
What is shale?
Shale is a fine-grained sedimentary rock exhibiting fissility. (h)
Turbidite
What is turbidite?
Turbidite forms in abyssal fans. (d)
Oolites
What are oolites?
Oolites are caviar-sized and shaped particles. (e)
Sand
What is sand?
Sand has a grain size of 1/16-2 mm. (a)
Gravel
What is gravel?
Gravel has a particle size of >2 mm. (c)
Pelagic sediment
What is pelagic sediment?
Pelagic sediment is deep-sea sediment without terrigenous material. (g)
The inflection point is where the change in _____ of a fold is observed.
a. length b. thickness c. shape d. curvature e. aota
d. curvature
From which hemisphere did India come? .
a. East b. West c. South d. North e. nota
c. South
Assign the beach ball symbols above to their proper representative geologic features.
a. 1: Normal Fault, 2: Oblique-slip Fault, 3: Reverse Fault, 4: Reverse Fault, 5: Strike-slip Fault
b. 1: Reverse Fault, 2: Reverse Fault, 3: Oblique-slip Fault, 4: Normal Fault, 5: Strike-slip Fault
c. 1: Reverse Fault, 2: Oblique-slip Fault, 3: Oblique-slip Fault, 4: Normal Fault, 5: Strike-slip Fault
d. 1: Strike-slip fault, 2: Oblique-slip Fault, 3: Oblique-slip Fault, 4: Strike Fault, 5: Dip-slip Fault
e. 1: Normal Fault, 2: Normal Fault, 3: Oblique-slip Fault, 4: Reverse Fault, 5: Strike-slip Fault
b. 1: Reverse Fault, 2: Reverse Fault, 3: Oblique-slip Fault, 4: Normal Fault, 5: Strike-slip Fault
Imagine that the material moves from white regions to shaded regions (white to shaded logic method).
Referring to your answer in (1), specifically to your beach ball/s corresponding to strike-slip fault, what kind of strike-slip faults are they? Identify the fault strikes as well.
a. Dextral only (either NE-SW or NW-SE)
b. Sinistral only (either NE-SW or NW-SE)
c. Either dextral or sinistral (dextral: NW-SE; sinistral: NE-SW)
d. Either dextral or sinistral (dextral: NE-SW; sinistral: NW-SE)
e. Both the natures of strike-slip faults and their corresponding strikes are unidentifiable.
c. Either dextral or sinistral (dextral: NW-SE; sinistral: NE-SW)
Use the white to shaded logic method. Check that indeed, there are two possible strike-slip configurations for figure 5. White region 1 (on the N) may go to shaded region 1 (on W) or on shaded region 2 (E). If white region 1 -> shaded region 1, so the other side should follow: white region 2 -> shaded region 2. This forms a strike slip fault whose orientation is NE-SW. If we follow the other thinking: white region 1 -> shaded region 2 and white region 2 -> shaded region 1, there is a visualized strike – slip whose strike is now NW – SE. The strike is reflected by either NE-SW and NW-SE lines.
Which of the figure numbers reflect a possible presence of thrust fault?
a. 1
b. 2
c. 3
d. 4
e. 5
b. 2
On figure 2: check the curves that separate the white and the shaded region. The less steeper curve (nearer to the plane of paper) corresponds to a lower dip of fault while the steeper curve (near the vertical) corresponds to a higher dip of fault. So the area could have a high or a low dip (thrust fault). Figure 1 does have two curves that are steep, so we do not expect a thrust fault here.
The __ axis bisects shear joints
a. σ₁
b. σ₂
c. σ₃
d. σ₁ and σ₂
e. nota
b. σ₂
The crust can be 0 km in thickness.
a. False b. Can’t say 0. True d. nota
a. False
