GEOL20210 Field Geology and Mapwork

Academic Year 2023/2024

Geological information in the field and on maps underpins the discovery and management of Earth’s resources, such as groundwater, geothermal energy and energy critical minerals. It is also fundamental to geohazard analysis and geotechnical engineering. This module will introduce you to: (1) the 3D principles and construction of geological maps; (2) the collection of primary geological data from rock outcrops in the field; and (3) the interpretation of geological data in space and time. Teaching comprises a set of practical classes and a six-day field course in the West of Ireland.

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Curricular information is subject to change

Learning Outcomes:

Upon completion of this module you should be able to:
(1) Read and interpret geological maps - and in particular deduce the 3D geometry of rock units and other geological features;
(2) Practice the rudiments of geological mapping, rock description and field data collection;
(3) Identify a range of common minerals, fossils and rocks in hand specimen and in the field, and be able to interpret their geological significance;
(4) Explain how sedimentary environments, igneous activity and metamorphic events can be reconstructed from map and field evidence;
(5) Record structural data (such as dip, strike, plunge and plunge direction) for various geological structures in the field using a compass-clinometer;
(6) Decipher an area’s geological history from a geological map, with particular emphasis on establishing the relative timing of different events.

Indicative Module Content:

Field Class (6 days)

1 West of Ireland
Dr E. P. Holohan & Dr. K. English – 11th-16th March
A six-day residential field course to examine evidence for the geological evolution of the West of Ireland, from ocean closure and mountain building about 470 Million years ago to the last Ice Age about 11,000 years ago. Also includes small-group training exercises on geological field description, measurement and mapping.


Practical Classes (3 hours)

1 Outcrop patterns on geological maps and their relationship to topography.
Dr E. P. Holohan – 15:00-18:00, Thursday 26th January
• Topographic contours and profiles. Stratigraphic columns. Structural contours. How topography affects geological map patterns. Complete Maps 1 & 4 in class. Complete Map 5 as homework to practice.
• Can you highlight to an engineering firm where a planned tunnel may need extra reinforcement?

2 Unconformities on geological maps
Dr E. P. Holohan - 15:00-18:00, Thursday 2nd February
• Main types of unconformity between rock sequences. Complete Map 10 in class. Complete Map 9 to practice your learning as homework.
• Can you tell an exploration company where to look for Zn/Pb deposits for green energy storage?

3 Folded rocks and related map patterns
Dr E. P. Holohan - 15:00-18:00, Thursday 9th February
• Folding of rocks and related terminology. Complete Map 12 & 16 in class.
• Can you advise a driller of where to locate copper ore deposits for green energy transmission?

4 NO CLASS (Science Day, Thursday 16th February)

5 Faults on geological maps and cross-sections
Dr E. P. Holohan - 15:00-18:00, Thursday 23rd February
• Normal, reverse and strike-slip faults on geological maps. Complete Map 17 in class and Map 22 as homework.
• Can you inform a Milk Processing Plant where to drill for an on-site groundwater supply?

6 Fold plunge and foliations
Dr E. P. Holohan - 15:00-18:00, Thursday 2nd March
• Plunging folds and related patterns in structural contours and unit outcrop. Relationship between folded bedding and foliation (cleavage). Complete Maps 24 and 40.

7 Preparation for the West of Ireland Field Trip
Dr P. J. Orr - 15:00-18:00, Thursday 9th March
• Overview of the upcoming field trip to the West of Ireland, including: (i) a summary of the regional geological and tectonic evolution, (ii) an introduction to use of field equipment such as the compass clinometer, (iii) guidance on keeping a good field notebook and (iv) a field safety briefing.

RESIDENTIAL FIELD CLASS (Mid-term Break - 11th-16th March)

8 Igneous rocks on geological maps
Dr E. P. Holohan - 15:00-18:00, Thursday 30th March
• Overview of the geometries and emplacement mechanisms of intrusive and extrusive igneous rock units.
• Deduce the forms and emplacement mechanisms of the igneous rocks on Map 29 and draw two cross-sections to illustrate your ideas.

9 Integrating maps and other geological data I
Dr E. P. Holohan - 15:00-18:00, Thursday 6thApril
• Unravel the lost map of Uncolldub. Identify the nature of the map units and begin to unravel the geological history.
• Advise your company on where best to search for geothermal energy.

10 Integrating maps and other geological data II
Dr E. P. Holohan - 15:00-18:00, Wednesday 13th April
• Continuation of work on the Uncolldub map. Deduce the geological history of the map area and summarise the related geological processes. Make a cross-section and a chronostratigraphic chart.

11 Real geological maps – Cheddar, England
Dr E. P. Holohan - 15:00-18:00, Wednesday 20th April
• Tackle the tasks and questions on the handout regarding the mainly siliciclastic and carbonate rock units on the Cheddar Map.
• Draw a cross-section by using the topographic profile provided.

12 Real geological maps – Eldama Ravine, Kenya
Dr E. P. Holohan - 15:00-18:00, Wednesday 27th April
• Tackle the tasks and questions on the handout regarding the igneous, sedimentary and metamorphic rock units shown on the Eldama Ravine Map.
• Advise on the nature and potential locations of geological hazards in this highly active area.

Student Effort Hours: 
Student Effort Type Hours


Field Trip/External Visits


Autonomous Student Learning




Approaches to Teaching and Learning:
Teaching and learning on this module comprises a set of practical exercises and activities that encompass: active/task-based learning; peer and group work; enquiry & problem-based learning; case-based learning; and student presentations. 
Requirements, Exclusions and Recommendations

Not applicable to this module.

Module Requisites and Incompatibles
GEOL20250 - Crystals to Sedimentary Rocks

GEOL20140 - Negotiated Field Geology 1

Field & Structural Geology (GEOL20060), Tectonics & Metamorphic Rocks (GEOL20070), Structural Geology & Tectonics (GEOL20090), Field Geology (Stage 2) (GEOL20130)

Assessment Strategy  
Description Timing Open Book Exam Component Scale Must Pass Component % of Final Grade In Module Component Repeat Offered
Continuous Assessment: Continuous assessment of practical class work Throughout the Trimester n/a Standard conversion grade scale 40% No


Examination: Final exam on practical and field work 2 hour End of Trimester Exam No Standard conversion grade scale 40% No


Fieldwork: Assessment of residential field class - Fieldwork Notes, Map, & Contribution to Field Work Unspecified n/a Standard conversion grade scale 40% No



Carry forward of passed components
Resit In Terminal Exam
Autumn Yes - 2 Hour
Please see Student Jargon Buster for more information about remediation types and timing. 
Feedback Strategy/Strategies

• Feedback individually to students, on an activity or draft prior to summative assessment
• Feedback individually to students, post-assessment
• Group/class feedback, post-assessment

How will my Feedback be Delivered?

Feedback will be provided on a weekly basis and will take the form of: (1) Oral feedback on activities prior to assessment (2) Oral and written post-assessment feedback individually to students and to the class as a whole;

‘An Introduction to Geological Structures and Maps’, 8th Ed., by G.M. Bennison, P.A. Olver & K.A. Moseley [ISBN: 9781444149609] *

‘Earth – Portrait of a Planet’ by S. Marshak

‘Foundations of Structural Geology’, 3rd Ed., by R.G. Park.

(* = available as an ebook in UCD Lbrary)