Exam 1 Chapters 1-3

Question 1

How do we examine deformation?

Answer 1

Through geometric, kinematic, and dynamic analysis

Question 2

What is geometric analysis?

Answer 2

Examine deformation through shape, orientation, and size

Question 3

What is kinematic deformation?

Answer 3

Examines deformation through the description of motion and displacement

Question 4

What is dynamic analysis?

Answer 4

Examines deformation through the study of forces causing deformation (separates observations from interpretations)

Question 5

What does a tectonic plate consist of

Answer 5

the crust and the upper mantle (lithosphere)

Question 6

Crust thickness

Answer 6

7-70km

Question 7

Mantle thickness

Answer 7

~2900km

Question 8

Core thickness

Answer 8

2900-6370km

Question 9

3 compositonal layers of the earth

Answer 9

crust, mantle, core

Question 10

5 rheological layers of the earth

Answer 10

lithosphere, asthenosphere, lower mantle, outer core, inner core

Question 11

What are transformations?

Answer 11

describe how original locations, orientations, shapes and/or sizes of volumes of rock or material points within volumes of rock become changed

Question 12

what are the four kinds of transformations?

Answer 12

translation, rotation, dilation, and distortion

Question 13

Rotation

Answer 13

a rotation of material points about some common axis

Question 14

translation

Answer 14

all points in a body move the same distance along parallel paths

Question 15

dilation

Answer 15

a change in size without a change in shape

Question 16

distortion

Answer 16

a change in shape of a body of rock

Question 17

rigid body deformation

Answer 17

each point within the body of rock maintains the same location related to the other points
- translation and rotation

Question 18

non-rigid body deformation

Answer 18

the spacing of points within the body of rock change with respect to one another
- dilation and distortion

Question 19

strain

Answer 19

results from non-rigid body deformation through change in size or shape
- results from change in spatial arrangement

Question 20

Primary structures

Answer 20

develop during the formation of a rock body

Question 21

examples of primary structures

Answer 21

cross bedding, ripple marks, graded bedding, ropy texture in basalt

Question 22

secondary structures

Answer 22

develop in rocks after their formation

Question 23

mohorovic discontinuity

Answer 23

the boundary between the earths crust and the mantle

Question 24

angular shear

Answer 24

measure of the change in angles between lines

Question 25

clockwise rotation

Answer 25

negative

Question 26

counterclockwise rotation

Answer 26

positive

Question 27

strain ellipse

Answer 27

distortion acuminated by a geologic body as a result of deformation

Question 28

what are S1 and S3

Answer 28

the principal axes of the finite strain ellipse

Question 29

S1

Answer 29

the long axis of the finite strain ellipse and the direction of maximum finite stretch

Question 30

S3

Answer 30

the short axis of the finite strain ellipse and the direction of minimum finite stretch

Question 31

plane strain

Answer 31

• the strain is two dimensional
• neither stretching or shortening in direction perpendicular to the plane that contains the directions of maximum and minimum finite stretch

Question 32

end case of coaxial deformation

Answer 32

pure shear

Question 33

coaxial deformation

Answer 33

lines that at the very first instant of deformation were aligned parallel to the direction of the long and short axes of strain (s1 and s3) will remain mutually perpendicular and parallel to the the long and short axes of the strain ellipse throughout the deformation

Question 34

pure shear

Answer 34

extension of the material will be balanced by the shortening

Question 35

non coaxial deformation

Answer 35

all particles move parallel to the direction of shearing but the directions of greatest stretch (s1) and least stretch (s3) continuously change, oblique to the direction of shearing

Question 36

what is used to portray how a circle would be affected by very small increments of deformation

Answer 36

instantaneous strain ellipse

Question 37

in coaxial deformation how is (s1.) related to (s1) and (s3.) to (s3)

Answer 37

they are parallel

Question 38

in non coaxial deformation how are (s1.) and (s1) related and (s3.) and (s3)

Answer 38

S1 is successively rotated out of parallelism with (s1.) same with (s3.) and (s3)

Question 39

how does normal stress act on the surface

Answer 39

perpendicular

Question 40

how does shear stress act on the surface

Answer 40

parallel

Question 41

9 stresses

Answer 41

3 are normal

6 are shear