Structures (Structural)

Question 1

Intracrystalline kink structures that resulted from strain through mechanical twinning, or twin gliding.

Answer 1

Deformation Twins

Question 2

Mechanical bending or kinking of the crystal lattice that resulted from stress. Twin Gliding-Involves simple shear along the twin plane once critical stress is reached.

Answer 2

Twinning

Question 3

A form of crystal defect that may either be vacancies, substitution or interstitial impurities within a crystal lattice.

Answer 3

Point Defect

Question 4

A gap or hole between atomic bonds in crystal lattices.

Answer 4

Vacancy

Question 5

Occurs when a different atom or molecule substitutes the original atom or molecule in its location.

Answer 5

Substitution

Question 6

Impurities that are locked within atoms or molecules of a crystal lattice.

Answer 6

Interstitial Impurity

Question 7

A mobile line defect or dislocation that contributes to intracrystalline deformation by slipping.

Answer 7

Line Defects

Question 8

a diffusion of vacancies through crystals that is temperature- and stress-controlled.

Answer 8

Nabarro-Herring Creep or Volume diffusion

Question 9

A mechanism that involves migration of vacancies in crystallographic lattices.

Question 10

diffusion of vacancies along grain boundaries that is temperature- and stress-controlled.

Answer 10

Coble Creep or Grain boundary diffusion

Question 11

a diffusion that is chemically- and stress-controlled and occurs along a thin film of fluid and pore fluid along grain boundaries.

Answer 11

Wet Diffusion

Question 12

A form of dislocation where an extra half-plane is placed between crystal lattices.

Question 13

A form of dislocation where the dislocation line is parallel to the slip direction, and half-plane of the crystal lattices slides across each other.

Answer 13

Screw Dislocation

Question 14

Any planar or subplanar discontinuity that is very narrow in one dimension compared to the other two and forms as a result of either an external or internal stress.

Answer 14

FRACTURE

Question 15

Extensional fractures filled with air or fluid.

Answer 15

Fissure

Question 16

Fractures that are filled with gas, fluids,
magma or minerals.

Answer 16

Extension Fractures

Question 17

anticracks, are fractures with contractional displacements across the fractures that are filled with residue from the rock.

Answer 17

Contractional Fractures

Question 18

A slip surface fracture along which there is a
large offset movement that is parallel to the fracture.

Answer 18

FAULT

Question 19

The relatively high footwall block between faults where the two adjacent faults dip away from one another.

Answer 19

Horst

Question 20

A fault-bounded block that drops down between two adjacent faults dip toward one another.

Answer 20

Graben

Question 20

A depression created as a consequence of the rotation accompanying displacement on a normal fault and the original top surface of the hanging wall block tilts toward the fault.

Answer 20

Half-Graben

Question 21

The bearing of the imaginary line formed by the intersection of the fault plane with a horizontal plane, found with an equal elevation.

Answer 21

Strike

Question 22

the bearing of the imaginary horizontal line perpendicular to the strike; Angle the vertical angle between an inclined plane and the dip direction, perpendicular to the strike.

Answer 22

Dip Direction

Question 23

The slip surface of a fault.

Answer 23

Fault Plane

Question 24

The rock block resting on top of the fault plane.

Answer 24

Hanging Wall

Question 25

The rock block positioned beneath the fault plane.

Answer 25

Foot Wall

Question 26

The horizontal component of the dip separation measured perpendicular to the strike of the fault.

Answer 26

Heave

Question 27

The vertical component in the vertical plane containing the dip.

Answer 27

Throw

Question 28

The combination of the vertical and horizontal component.

Answer 28

Oblique Slip

Question 29

The total amount of displacement measured parallel to the direction of the motion.

Answer 29

Net Slip

Question 30

the angle formed from an inclined plane between a horizontal line and a line in question.

Answer 30

Rake (B) or Pitch

Question 31

The vertical angle between an inclined plane and a horizontal line that is not perpendicular to the strike of the plane.

Answer 31

Apparent dip

Question 32

For any inclined plane (except a vertical one), the true dip is always greater than any apparent dip.

Question 33

An apparent dip may be defined by its _________ or by its _______ within a plane.

Answer 33

trend and plunge ; pitch

Question 34

The orientation in space of a line or plane.

Answer 34

Attitude

Question 35

By convention, the attitude of a plane is expressed as its strike and dip; the attitude of a line is expressed as trend and plunge.

Question 36

Method of expressing the strikes of planes and trends of line based on a 360° clockwise circle. Azimuthal bearing always starts from the due north.

Answer 36

Azimuth method

Question 37

The horizontal angle between a line and a specified coordinate direction, usually true north or south; the compass direction or azimuth.

Answer 37

Bearing

Question 38

The plunge of the true dip.

Answer 38

Delta

Question 39

The vertical angle between a line and the horizontal.

Answer 39

Plunge

Question 40

Method of expressing strikes of planes and trends of lines based on four 90° quadrants.

Answer 40

Quadrant method

Question 41

The direction (trend) of the apparent dip.

Answer 41

Theta

Question 42

The bearing (compass direction) of a line. Non-horizontal lines trend in the down-plunge direction.

Answer 42

Trend

Question 43

An array of faults in a strike-slip fault zone that merges at depth into a near-vertical fault plane, but near the ground surface diverges so as to have shallower dips.

Answer 43

Positive FLOWER STRUCTURE

Question 44

A flower structure where there is a component of normal faulting.

Answer 44

Negative Flower Structure

Question 45

Occurs where two subparallel thrusts of approximately equal displacement are separated by a deformed interval that is thin relative to its total area extent.

Answer 45

DUPLEX

Question 46

develops where thrust sheet has been antiformally folded, causing part of the sheet to have a higher elevation.

Answer 46

FENSTER Or Window

Question 47

Dismemberment of a thrust sheet by erosion.

Answer 47

KLIPPE

Question 48

A rock that is still in its place of origin; the footwall below a detachment.

Answer 48

AUTOCTHON

Question 49

A rock that has moved from its place of origin; the thrust sheet above a detachment.

Answer 49

ALLOCTHON

Question 50

A structural feature that is formed when planar features are bent or curved.

Answer 50

FOLDS

Question 51

PARTS OF FOLDS

Answer 51

Hinge Hinge Zone Hinge Point Limb Amplitude

Question 52

The gradual, or sharp and abrupt, curvature of the fold. Hinge Line - The line of greatest curvature.

Answer 52

Hinge

Question 53

The area where the fold hinges.

Answer 53

Hinge Zone

Question 54

The point of maximum curvature of the folded layer located within the hinge zone.

Answer 54

Hinge Point

Question 55

The less curved portion of a fold.

Answer 55

Limb

Question 56

Half the height of the fold, measured from the crest to trough.

Answer 56

Amplitude

Question 57

The surface containing the hinge lines from consecutive folded surfaces.

Answer 57

Axial Surface

Question 58

The topographically highest point of a fold, which need not coincide with the fold hinge.

Answer 58

Crest

Question 59

High point of the hinge line in a non-cylindrical fold.

Answer 59

Culmination

Question 60

Fold in which a straight hinge line parallels the fold axis; in other words, the folded surface wraps partway around a cylinder.

Answer 60

Cylindrical Fold

Question 61

Low point of the hinge line in a noncylindrical fold.

Answer 61

Depression

Question 62

Fold generator in cylindrical folds.

Answer 62

Fold Axis

Question 63

The position in a limb where the sense of the curvature changes.

Answer 63

Inflection Point

Question 64

Fold with a curved hinge line.

Answer 64

Non-cylindrical Fold

Question 65

The topographically lowest point of a fold, which need not coincide with the fold hinge.

Answer 65

Trough

Question 66

The distance between two hinges of the same orientation.

Answer 66

Wavelength

Question 67

More or less regularly-shaped rectangular fragments formed by stretching of competent layers or foliations.

Answer 67

BOUDINS

Question 68

The process that leads to the formation of boudins from originally continuous layers.

Answer 68

Boudinage

Question 69

Regularly-spaced areas of thinning in many extended competent layers without the separation into isolated fragments or boudins.

Answer 69

PINCH-AND-SWELL STRUCTURES

Question 70

Circular or elliptical structural or topographic highs in which beds dip away to all directions; when eroded, the oldest rocks are exposed at the center.

Answer 70

DOMES

Question 71

Circular or elliptical structural or topographic lows or downwarps in which beds dip towards the center; when eroded, the youngest rocks are exposed at the center.

Answer 71

Basin

Question 72

the presence of layers with different competencies directly affects the strain pattern in the deforming body and there is contrasting behavior between layers.

Answer 72

Flexural folding Or active folding,

Question 73

A dynamic condition in active folding where the applied force is oriented at an oblique angle to the layering.

Answer 73

Bending

Question 74

The most common situation for folding, is a dynamic condition in active folding where the force is oriented parallel to the mechanical anisotropy.

Answer 74

Buckling