Introduction

Question 1

Tectonics

Answer 1

structure and tectonics interact, cant draw a line between them

tectonics are external processes that cause a characteristic set of structures in an area

plate tectonics

salt tectonics

neotectonics
- crustal motions and contemporaneous stress field

Question 2

plate tectonics

Answer 2

• movement and interaction of lithospheric plates
  there are major and smaller plates
  plate boundaries join to form a network
  example of subduction ->indian plate started to collide with Asia about 15 million years ago

Question 3

salt tectonics

Answer 3

salt is a rock
- deformation from vertical movement of salt through its overburden
-layers of salt cut through the sedimentary layers above them
-salt is not permeable

Question 4

deformation

Answer 4

conglomerate (large clasts, matrix supported) -> clasts can get flattened or stretched

different rocks behave differently under the same conditions
->not all rocks deform in the same way under the same chemical an physical conditions

the same rock will behave differently depending on the chemical and physical conditions (HPT vs LPT)

usually high pressure and high temperature go together ->not always

Question 5

stress

Answer 5

stress on a plane is the force per unit area of the plane

stress = force/area

the same force applied on a smaller area will cause more damage

Question 6

deformation and strain

Answer 6

any change in shape/distortion (strain), position (translation), or orientation (rotation) of a body under stress
3 components: rotation, translation, and strain

as long as a rock has one of three components, you can say it is deformed

Question 7

homogeneous vs inhomogeneous (heterogeneous)

Answer 7

homogeneous -> everything has moved/been changed in the same way

Question 8

factors that affect deformation

Answer 8

different rock types (chemical/mineralogical composition)
->have different chemical properties

physical and chemical environments

Question 9

main types of structures

Answer 9

Non-tectonic (primary)
->not due to deforming forces
->formed during the formation of the rock

Tectonic (secondary)
1. Brittle structures
2. Ductile structures

Question 10

types of tectonic structures

Answer 10

brittle -> loss of cohesion

ductile -> no loss of cohesion

Question 11

scale of observations

Answer 11

microscopic
-> only visible under thin section

mesoscopic
-> can be observed directly
-> from hand samples to large, continuous outcrop

macroscopic
-> several outcrops to whole mountain ranges
-> cant be observed directly, need interpretation

Question 12

methods in structural geology

Answer 12

fieldwork - most essential

other techniques - data and modelling, measuring crystallographic orientation of constituent crystals, look at structural details within individual crystals

Question 13

structural analysis

Answer 13

2 distinct steps:

1. study and description of a rock in its present state

2.

Question 14

geometric analysis

Answer 14

geometrical features are studied
infer what the geometry is, descriptive, free from reference

characterization of the form, extent, and arrangement of structures in a map area

Question 15

kinematic analysis

Answer 15

from the results of the geometrical analysis
-> attempt to reconstruct movements that took place during the deformation of the rock
-> rotation, translation, strain

how the geometric formed

Question 16

dynamic analysis

Answer 16

what kind of forces led to the movement & formation of the structures

Question 17

tectonic analysis

Answer 17

Uses data (structural, stratigraphic, etc.) to analyze the tectonic processes that were involved in the geological evolution of an area

ie. how did tectonic processes contribute to the current geology of an area