Structural Exam 2 But Better

Question 1

Hinterland

Answer 1

The direction towards the more deformed

Question 2

Foreland

Answer 2

Direction towards the undeformed

Question 3

Allochthonous

Answer 3

The part that is moving

Question 4

Autochthonous

Answer 4

The part that isn’t moving

Question 5

Decollement

Answer 5

The stationary, more competent layer under the surface that contributes to the thin-skinned deformation

Question 6

What is Critical Taper theory

Answer 6

Deformation in the hinterland builds to the critial taper, once reached the thrust sheet moves.

Question 7

What ways is the critical angle restored?

Answer 7

By forming a thrust fault, eroding the hinterland, and normal faulting caused by gravity

Question 8

Duplex

Answer 8

Thrust sheet that has a floor thrust and a roof thrust

Question 9

Free folds

Answer 9

based entirely on physical mechanical properties

Question 10

forced folds

Answer 10

requires bending and stretching

Question 11

Fault-bend-fold

Answer 11

The start of a duplex

Question 12

Forced-propagation-fold

Answer 12

The start of an imbricate fold

Question 13

Releasing bends

Answer 13

curve in the fold that causes a gap

Question 14

Restraining bends

Answer 14

curve in the fold that causes bunches

Question 15

What is the result of releasing bends

Answer 15

extension
normal faults
Grabens/basins

Question 16

What is the result of Restraining bends

Answer 16

Compression
Reverse faults
uplift/mountains

Question 17

In a left lateral slip, which direction is the Riedel shear pointed?

Answer 17

Right (opposite)

Question 18

In a left lateral slip, which direction is the en echelon array pointed?

Answer 18

left

Question 19

Stratography is known

Answer 19

____cline

Question 20

Stratography is unknown

Answer 20

____form

Question 21

Stratography is normal

Answer 21

Young over old

Question 22

Stratgraphy is not normal and peaks upward

Answer 22

antiformal syncline

Question 23

Stratography is not normal and peaks downward

Answer 23

synformal anticline

Question 24

in sequence thrusting

Answer 24

a thrust sequence that has formed progressively and in order in one direction

Question 25

step over to the left

Answer 25

compression

Question 26

step over to the right

Answer 26

extension

Question 27

Transpression

Answer 27

Transform body with compression

Question 28

Transtension

Answer 28

Transform body with extension

Question 29

Overturned

Answer 29

At least 1 limb is rotated beyond vertical

Question 30

Hinge line

Answer 30

line of max curvature on a folded surface

Question 31

Limb

Answer 31

side of the arch before the crest

Question 32

axial surface/plane

Answer 32

surface that contains hinge lines from consecutive folded surface

Question 33

fold axis

Answer 33

in cylindircal fold, it is the part that resembles a fold around a tube. Also known as straight line hinge

Question 34

Kink fold

Answer 34

Lightning bolt emoji

Question 35

Chevron fold

Answer 35

sharp angles, cartoon shark teeth

Question 36

Box fold

Answer 36

boxy or omega shaped

Question 37

Ptygmatic folds

Answer 37

no consistancy, wiggly worms

Question 38

Where and why do foreland basins form?

Answer 38

Form at the base of mountains and are result of immense mass on top, resulting in bending to compensate

Question 39

A flat ramp flat fault formed in a fold and thrust sheet promotes development in which type of fold

Answer 39

fault bend fold

Question 40

Buckling

Answer 40

Force from either side causing it to eventually buckle/bend

Question 41

Passive folding

Answer 41

layering with no mechanical significance formed by differential slip/flow along closely spaces planes fake folding

Question 42

Bending

Answer 42

rock is stretched, causing forces from above and below to concave the middle

Question 43

Boudins

Answer 43

Rock anal beads

Question 44

Laccoliths

Answer 44

Volcano that never breached the surface, depositing igneous rock below the surface causing a bulge above.

Question 45

Class 1 A folds

Answer 45

Thicker limb, thinner hinge

Question 46

Class 1B folds

Answer 46

limb = hinge thickness

Question 47

Class 1C folds

Answer 47

Thinner limbs, thicker hinge

Question 48

Class 2 fold

Answer 48

curvature of outer arc is same as inner arc

Question 49

Class 3 folds

Answer 49

curvature of outer arc is tighter than inner

Question 50

When viewing the cross section of a folding sequence of rocks, an imaginary line that connects the hinges of the fold from each layer defines the:

Answer 50

Axial trace

Question 51

Folds that have stretched outer arcs and compressed inner arcs are called

Answer 51

neutral surface folds

Question 52

What causes neutral surface folds

Answer 52

orthogonal flexure

Question 53

T of F: Another term for buckling is active folding

Answer 53

False, bending

Question 54

Fold vergance

Answer 54

axial trace is rotated Instead of arcs, its white caps

Question 55

What factors effect wavelength

Answer 55

thickness strength strength of surrounding rock

Question 56

The symbol for anticline

Answer 56

Horizontal line with arrows pointed away north and south of it

Question 57

Symbol for syncline

Answer 57

Horizontal line with arrows pointed in north and south of it

Question 58

Overturned symbol

Answer 58

Arrows on a curve pointing towards hinge line

Question 59

Recumbant fold

Answer 59

Fold that is on is side

Question 60

Two strong buckled sandstone layers produce class 1B folds. A weak shale layer in between the two layers is likely to produce what class of fold?

Answer 60

Class 3 fold

Question 61

When looking at an image where a quartz vein goes from straight in section a to wiggly in section B, what differences can be said about the surrounding rocks?

Answer 61

A is more resistant aka less viscous

Question 62

T or F, a non-cylindrical fold does not have a fold axis

Answer 62

True

Question 63

T or F, a viscosity difference is needed for buckling to occur

Answer 63

True

Question 64

What does it mean that parasitic folds show vergence?

Answer 64

They are asymmetrical

Question 65

In a flexural slip/flexural flow, which part will have the most strain?

Answer 65

The limbs

Question 66

In orthogonal flexure, where is the most strain?

Answer 66

The hinge