Introduction

Question 1

What is structural geology

Answer 1

-ways in which rocks respond to application of deforming forces

-structures that result from deformation.

Question 2

What is a geological structure and give examples

Answer 2

-a geometrical feature in rock whose
shape, form and distribution can
be described.

-folds, foliations, lineations, faults and joints.

Question 3

What are tectonics and the 3 types

Answer 3

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

plate tectonics
- movement and interaction of lithospheric plates

salt tectonics
-deformation from vertical movement of salt through its overburden

neotectonics
- crustal motions and contemporaneous stress field

Question 4

Do all rocks, irrespective of their different chemical and mineralogical compositions, deform in the same way under the same chemical and physical conditions?

Does the same rock deform in the same way under different chemical and physical conditions (e.g., HPT vs. LPT)?

Answer 4

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)

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

what factors affect deformation

Answer 6

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

the physical and chemical environments in which deformation occurs (high TP vs low TP)

Question 7

main types of structures
(classification scheme based on timing of formation)

Answer 7

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

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

Question 8

types of tectonic structures

Answer 8

brittle -> loss of cohesion

ductile -> no loss of cohesion

Question 9

scale of observations

Answer 9

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 10

methods in structural geology

Answer 10

fieldwork - most essential

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

Question 11

what are the 2 steps of structural analysis

Answer 11

2 distinct steps:

1. study and description of a rock in its present state
   -as free as possible from inference and extrapolation
2. Genetic interpretation of the descriptive data, an attempt to reconstruct evolution of the geologic body in question

Question 12

describe geometric analysis

why is inference often necessary

Answer 12

type of structural analysis:

• characterization of the form, extent, and spacial arrangement of structures in a map area
• determining the chronological sequence in which these structures formed
• observations made on a smaller scale are used to draw inferences about large scale structures

Ideally it is descriptive and free from inference (descriptive analysis). In practice, inference is often necessary because outcrop is rarely continuous.

Question 13

describe kinematic and dynamic analysis

Answer 13

the results from the geometric analysis are used to perform kinematic and dynamic analyses

kinematic analysis:
-determine what movements created the structures from the geometric analysis
-rotation, translation, & strain that took place during the deformation of the rock

dynamic analysis
- determine what kind of forces led to the movement & formation of the structures
- stresses related to movements and the formation of the structures

Question 14

tectonic analysis

Answer 14

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

Question 15

applications of structural geology

Answer 15

1. Geological study
2. Geo-engineering design
3. Mineral deposit study and mineral
   exploration (because deformation can
   modify the geometry and/or control the location of ore bodies)
4. Groundwater and petroleum research (e.g., structures as fluids conduit and trap)