8 - Fabrics

Question 1

is the geometric arrangement of component features in the rock.

Answer 1

Fabrics

Question 2

formed during the genesis of the rock.

Answer 2

Primary fabrics

Question 3

Products of ductile deformation and are systemically associated with tectonic stress

Answer 3

Secondary Fabrics

Question 4

Secondary fabrics are commonly observed in?

Answer 4

Tectonites

Question 5

Dominantly a foliation; rock may tend to split into sheets parallel to the foliation.

Answer 5

S-tectonites

Question 6

Alignment of linear fabric elements creates the dominant fabric, so the rock may split into rod-like shapes.

Answer 6

L-tectonites

Question 7

A strong foliation and a strong lineation

Answer 7

L/S-tectonites

Question 8

fabric elements have no preffered orientation

Answer 8

Random

Question 9

fabric elements are aligned in some manner and/or repeated an approx. regular spacing

Answer 9

Preferred

Question 10

fabric elements are planar or tabular features and parallel to one another.

Answer 10

Planar (or foliation)

Question 11

fabric element is a linear feature.

Answer 11

Linear (or lineation)

Question 12

has spaced visible between the fabric elements.

Answer 12

Spaced Fabric

Question 13

continues to be visible no matter how small your field of view.

Answer 13

Continuous fabric

Question 14

Describes the arrangement of any kind of sub-parallel, closely spaced and low cohesion surfaces.

Answer 14

Foliation

Question 15

Development of foliation depends on? (3)

Answer 15

Composition
Temperature
Depth of burial

Question 16

Involved in the development of diverse foliations (3)

Answer 16

Mechanical rotation
Solution/precipitation
Crystallization and recrystallization

Question 17

All of these mechanisms tend to produce a preferred dimensional orientation of non equant grains and/or aggregates of grains that define?

Answer 17

Planar structure

Question 18

A secondary fabric element, formed under low-T conditions, that imparts on the rock a tendency to split along planes.

Answer 18

Cleavage

Question 19

Forms mostly in sedimentary rocks that have been subjected to a tectonic differential stress that leads to progressive horizontal shortening of sedimentary beds.

Answer 19

Disjunctive cleavage

Question 20

Are heterogeneously distributed lamellae where the fabric and mineralogy of the host rock have been altered so that minerals show a preferred shape and/or crystallographic orientation.

Answer 20

Cleavage domains

Question 21

Because pressure solution is always
involved in the formation of a
disjunctive cleavage, what kind of cleavage can also form?

Answer 21

Stylolitic cleavage

Question 22

is a low-temperature tectonic fabric formed due to shortening of clay-rich sediments like mudstones.

Answer 22

Pencil cleavage

Question 23

have a strong dimensionally preferred orientation of phyllosilicates in a very clay-rich rock. Tends to be smooth and planar.

Answer 23

Slaty cleavage

Question 24

Created when an earlier foliation is folded (crenulated) on a meso- to micro-scale and will be overprinted by a new foliation, with a new orientation, that refolds the previous structure.

Answer 24

Crenulation cleavage

Question 25

Type of cleavage when metamorphic conditions reach the lower greenschist facies, the clay and illite in a pelitic rock react to form white mica and chlorite. These phyllosilicates grow with a strong preferred orientation.

Answer 25

Phyllitic cleavage

Question 26

When metamorphic conditions reach upper greenschist facies to lower amphibolite facies, the mica grains grow larger and become easily discerned with a naked eye. The foliation is no longer a cleavage.

Answer 26

Schistosity

Question 27

Type of foliation at even higher grades, metamorphic rocks may develop compositional layering because different minerals recrystallize and form new ones in bands that are parallel to the direction of stress.

Answer 27

Gneissic foliation

Question 28

Sedimentary protolith

Answer 28

paragneiss

Question 29

Igneous protolith

Answer 29

orthogneiss

Question 30

A special type of gneiss that contains relatively large feldspar clasts floating in a finer-grained matrix.

Answer 30

Augen gneiss

Question 31

is formed by the accumulation of large shear strain, in ductile fault zones. High strains flatten objects and thin layers.

Answer 31

Mylonitic foliation

Question 32

Foliation in folded rocks is subparallel (ideally, parallel) to the axial plane in the fold hinges produced by the same deformation event.

Answer 32

Axial plane foliation

Question 33

This change of angular relationship between foliation and bedding across lithological boundaries is termed?

Answer 33

Cleavage refraction

Question 34

Axial plane foliations typically display a radiating pattern within the fold.

Answer 34

Foliation fan

Question 35

Any fabric element that can be represented by a line, meaning that one of its dimensions is much longer than the other two.

Answer 35

Lineations

Question 36

is the fabric element parallel to the tightly spaced hinges.

Answer 36

Crenulation lineation

Question 37

Cylindrical structures developed at the interface between rocks of different competence shortened along the layering.

Answer 37

Mullions

Question 38

Elongate, cylindrical and monomineralic bodies of segregated mineral (quartz, calcite, pyrite, etc.) in metamorphic rocks of all grades.

Answer 38

Rods

Question 39

The parallel alignment of individual grains, aggregates or fragments of any size that have been elongated and/or rotated during deformation is an important type of lineation.

Answer 39

Stretching lineations

Question 40

Metamorphic minerals often grow with a preferred crystallographic and dimensional orientation within a foliation plane delineated as?

Answer 40

mineral lineations