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School of Environment, Education and Development

Students on a field trip
BSc Geography and Geology
Benefit from a wide range of optional topics and practical trips on this combined degree.

BSc Geography and Geology

Year of entry: 2018

Course unit details:
Structural Geology

Unit code EART20292
Credit rating 10
Unit level Level 2
Teaching period(s) Semester 2
Offered by School of Earth and Environmental Sciences
Available as a free choice unit? No

Overview

This unit provides a comprehensive introduction to the field of Structural Geology. It builds upon the 1st year unit on Geological Maps (EART10122), and complements material covered within the 2nd year field courses (EART20300). It provides the necessary grounding in all the structural techniques required by those students undertaking the Independent Field Mapping exercise (EART30000) at the end of the 2nd year, while also providing the prerequisites for those planning to pursue further studies in structural processes and geomechanics (engineering geology, petrophysics) within their 3rd year.

The lectures provide an overview of the subject, describing the geometry of geological structures (folds, fractures, and faults/shear zones) and their associated minor structures, together with the key mechanical concepts of stress, strain and microscale rock deformation mechanisms. The last three lectures seek to integrate the preceding eight by describing the interrelationships between these structures in contractional, extensional and strike-slip tectonic settings. Examples are taken from other planetary bodies in addition to Earth. The lectures are densely packed with content so that the overview of the subject is comprehensive – it is intended that the students can use the PowerPoint presentations (with the expanded set of comments/further reading on the notes pane to each slide) as a reference source when dealing with related material in any future course unit that they might do. As such, this is a road map of the subject – different students will focus on different aspects. Assessment, however, focuses on key material (highlighted within each lecture) that any geologist should be familiar with.

The practicals develop a working understanding of structural analysis. There is a particular (but not exclusive) emphasis on techniques that students might use while undertaking their Independent Mapping Exercise. Several practicals focus on the use of stereonets for analysing the geometry of folds and faults and for constructing cross sections on dipping planes to illustrate that geometry. Two practicals are devoted to stress and strain analysis to develop the content of the lectures on those subjects which would otherwise be very abstract. In the last three practicals, an introduction to cross section restoration techniques in contractional and extensional tectonic settings is given, as well as exercises in using minor fractures and fabrics associated with faults/shear zones to establish the kinematics of larger scale faults.

Pre/co-requisites

Unit title Unit code Requirement type Description
British Stratigraphy / Geological Maps EART10122 Pre-Requisite Compulsory

Aims

This course unit aims to provide:

  1. an outline of the key geometric features that are found in deformed rocks
  2. practical training in the analysis of geological structures

 

Syllabus

Week 1:

Lecture: basic geometrical features of folds and their associated minor structures

Practical: the use of the stereonet for analysing the geometry of folds

Week 2:

Lecture: How folds form

Practical: Consolidation session on analysing and illustrating the geometry of folds using the stereonet; folded lineations; introduction to compiling an evidence-based structural history

Week 3:

Lecture: Strain

Practical: Finite strain measurement techniques

Week 4:

Lecture: Shear zones

Practical: Analysing and illustrating the geometry of faults using the stereonet

Week 5:

Lecture: Rock deformation mechanisms (how rocks deform)

Practical: Consolidation session on analysing and illustrating the geometry of faults using the stereonet

Week 6:

Lecture: Stress

Practical: Stress analysis using Mohr’s circle

Week 7:

Lecture: Fracturing and the emplacement of minor intrusions

Practical: Constructing accurate fold profile plane cross sections

Week 8:

Lecture: Faulting

Practical: Refolded folds on maps; revisiting evidence-based structural histories

Week 9:

No class (Easter field courses)

Week 10:

Lecture: Contractional tectonic regimes

Practical: Restoring and balancing cross sections in contractional terrains

Week 11:

Lecture: Extensional tectonic regimes

Practical: Constructing sections across extensional fault terrains

Week 12:

Lecture: Strike-slip tectonic regimes

Practical: Analysing brittle and ductile shear zone fabrics

Teaching and learning methods

The lectures are posted as PowerPoint presentations on Blackboard. These are augmented with substantial extra notes (comments/further reading) in the notes pane to each slide, and also with some supplementary documents. The students are expected to learn the lecture material primarily by reading this material on Blackboard and to view attendance at the lectures themselves as an initial once-through the material that makes the subsequent independent study more efficient. A short document is posted on Blackboard each week highlighting the key intended learning outcomes from that week’s lecture, together with examples of how this might be assessed in the final theory examination. Additional comments are provided within the short formative feedback sessions in the practicals.

The practical material is delivered through a number of carefully selected exercises. Helpful hints on solution strategy or practical demonstrations are given. Staff and postgraduate demonstrators are on hand in the classes to guide students through the exercises as they work on them. It is through these exchanges that most formative feedback is delivered. During the practicals interim solutions are posted on the board in timely fashion. At the end of the class all exercises and solutions are posted on Blackboard. After most classes further practice exercises are included. Solutions to these are demonstrated within a short formative feedback session at the start of the following week’s class, and these are also posted on Blackboard. There is no assessment requirement for students to do these extra practice exercises but they are designed to be very helpful to those students who do.

Information on ‘How to do well in this unit’ is posted on Blackboard and underscored in the classes. This includes reference to strengths and weaknesses in student performance in previous years.

 

Knowledge and understanding

  • have an understanding of the significant geometric features of folds, faults, shear zones, and minor fractures
  • have an appreciation of how these field scale structural elements combine in larger scale contractional, extensional, and strike-slip tectonic settings
  • have an introductory knowledge of stress, strain, and rock deformation processes

Intellectual skills

  • begin to develop an appreciation of the way in which mechanical analysis (stress, strain, rock properties), microscale processes (rock deformation mechanisms), mesoscale structures (geometry of folds and faults), and macroscale features (plate tectonic processes) are aspects that need to be integrated to arrive at a general geodynamical understanding (outcome not explicitly assessed)

Practical skills

  • be able to carry out a comprehensive analysis and description of the geometry of folds
  • be able to carry out a comprehensive analysis and description of the geometry of faults
  • be able to construct accurate and appropriately oriented (i.e., typically fold profile plane or fault plane) cross-sections to illustrate the geometry of structural features

Transferable skills and personal qualities

  • be able to build an evidence-based argument for an interpretation (here a structural analysis), which is explained succinctly, with the logic flow made explicit, and which is illustrated with pertinent diagrams
  • develop an appreciation of the importance of following specific conventions when presenting geometric analyses to other scientists
  • be able to sift through a large body of information to separate parts that are directly relevant (e.g., to the structures in a student’s Independent Mapping field area) from those of marginal relevance, and to target extra reading on the former

Assessment methods

Method Weight
Other 50%
Written exam 50%

(1) Written ‘theory’ examination in May; diagrammatic, plotting, short answer questions primarily on lecture content but incorporating aspects that were developed in the practicals (e.g., stress and strain analysis). 2.5 hours  (50%)

As an end-of-unit examination, no formal feedback will be given. However, students may view their script, together with a very detailed mark breakdown, after the exam period by arrangement

 

(2) Written ‘practical’ examination in May; map-based exercise with accompanying short answer questions focusing on analysis of the geometry of folds and faults.  2.5 hours    (50%)

As an end-of-unit examination, no formal feedback will be given. However, students may view their script, together with a very detailed mark breakdown, after the exam period by arrangement

 

 

Feedback methods

 

 

Recommended reading

Core reading:

  • Fossen H, 2016, Structural Geology (2nd edition). Cambridge University Press
  • Lisle RJ, Leyshon PR, 2004, Stereographic Projection Techniques for Geologists and Civil Engineers (2nd edition). Cambridge University Press

 

Excellent alternative/additional reading:

  • Twiss RJ, Moores EM, 2007, Structural Geology (2nd edition). W.H. Freeman & Co.
  • Price NJ, Cosgrove JW, 1990, Analysis of Geological Structures. Cambridge University Press
  • ·Ragan DM, 2009, Structural Geology: An Introduction to Geometrical Techniques (4th edition). Cambridge University Press

Study hours

Scheduled activity hours
Lectures 11
Practical classes & workshops 33
Independent study hours
Independent study 56

Teaching staff

Staff member Role
Stephen Covey-Crump Unit coordinator

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