GLY 256 Geology for Engineering
Mrs. Adri Deysel (Alberts)
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About this Module
• Lecturer:
⚬ Ms Adri Deysel
⚬ Office: MS 4-32
• Practical tutor:
⚬ Ms Vusani Mathada
• Refer to the Studyguide and the Departmental Handbook
• Class guardian:
• Prof Lorenzo Milani
• Ask – you are here to learn, and we are most willing to teach you,
but you should use the appropriate opportunities
• Module coordinator
• Dr Ansie Smit
• Class attendance is compulsory; above that, you should WANT
to be here, otherwise the next few years are going to be very
hard
available by appointment
made via email, or at the
times stipulated on their
office doors
2025/02/07
• You will be required to do self-study – get used to it early on
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About this Module
• Prescribed book
⚬ Earth Portrait of a Planet
⚬ Stephen Marshak. 2018 6ᵗʰ ed. Earth Portrait of a Planet.
WW Norton & Co. ISBN: 9780393640137
⚬ ANY EDITION!
• Presentation slides will be posted on ClickUP.
• You should take notes during lectures
• The textbook will help, but most important is to understand
the content discussed during lectures
• Practicals will take place in the First Year Lab – MS 4-22
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About this Module
• Recommended book
⚬ The Story of Earth & Life: A southern African perspective on
a 4.6-billion-year journey.
⚬ McCarthy, T. and Rubidge, B. (2005) The Story of Earth &
Life. Struik Publishers. ISBN: 978 177007 148 3
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Study Guide
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Practicals
• Practicals will take place in the First Year Lab – MS 4-22
• Attendance is compulsory
• you need a 90% attendance for practicals to get exam entrance
• If you miss a prac you must provide a valid doctor’s note
• Due to LIMITED SEATS in the practical hall, students must enroll in their assigned study programs.
• Students in the study program S2 must enroll in the Wednesday group. Student in the study program s3 or
P3 must enroll in the Friday group.
Available slots:
1. Wednesday 08:30-10:30
2. Friday 13:30 - 15:30
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Quick Poll
What engineering
degree are you
registered for?
https://s.surveyplanet.com/136oq3tm
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GLY 256 Geology for Engineering
Why Geology?
What is Geology
• Geology
•
•
surface
interior
history
laws of natural
sciences
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Why Study Geology? Interest?
‘Civilization exists by geological consent, subject to change without notice.’
Will Durant (American historian; 1885-1981)
‘The scientist does not study nature because it is useful; he studies it because he delights in it, and
he delights in it because it is beautiful. If nature were not beautiful, it would not be worth knowing,
and if nature were not worth knowing, life would not be worth living.’
Henri Poincarè (French Mathematician; 1854-1912)
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Why Study Geology? Interest?
Hawaii
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Why Study Geology? Interest?
Mt Everest
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Why Study Geology? Money & Resources?
• Mining and economy: diamonds
• Star of the Season: the most expensive diamond ever sold
(Pink Star )
⚬ Flawless weighing 59.6 carats
⚬ (1 carat = 0.2 g; 59.6 * 0.2 = 11.92 g)
⚬ The Pink Star was mined by De Beers in 1999 in South
Africa
⚬ Date Sold: April 2017 in Hong Kong
⚬ C. $71 million R1 283 104 900
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Why Study Geology? Money & Resources?
• Mining and economy: platinum
• 30 times rarer than gold
• 80% of the worlds Pt reserves are in South
Africa
⚬ Associated with the Bushveld Igneous
Complex
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Why Study Geology? Money & Resources?
Without geological resources:
Mining and economy:
⚬ Uranium – Nuclear power
⚬ Iron – Steel
⚬ Silicon – computer chips
⚬ Coal – power/fuel
⚬ Limestone – cements
⚬ Gypsum - plaster
⚬ Oil – fuel
⚬ Sand – glass, bricks
⚬ Nickel, Copper, Manganese,
Titanium etc
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⚬ No TV
⚬ No mobile phones
⚬ No jewellery
⚬ No cars
⚬ No brick or metal houses
⚬ No fertile soils to grow crops
⚬ No groundwater
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Why Study Geology? Development?
• Minerals and commodities
⚬ Metals
⚬ Coal
⚬ Gemstones
⚬ Petroleum, oil and gas
• Construction materials
⚬ Clay (bricks; tiles; etc.)
⚬ Dimension stone (crystalline rock;
marble)
⚬ Crusher rock and sand (aggregate)
⚬ Dolomite (cement; aggregate)
⚬ Sand (glass)
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• Fossils etc.
• Groundwater
⚬ Drinking water
⚬ Wetland and ecosystem biodiversity
⚬ Hot springs, geysers
• Soil
⚬ Habitat and ecosystem biodiversity
⚬ Growth medium
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Why Study Geology? Development?
Construction of the De Hoop Dam near Steelpoort, 2009
• Why? Water scarcity
• How?
⚬ Foundation of dam wall
⚬ Construction materials
⚬ Structural geology
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Why Study Geology? Development?
• Construction of the Hatfield Station of the
Gautrain, Pretoria, 2008
• Why? Upgrading the standard of living
• How?
⚬ Deep excavations
⚬ Construction materials
⚬ Foundation and basements
⚬ Hydrogeology
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Why Study Geology? Development?
• Construction of the Centurion piers of the Gautrain,
2008
• Why?
⚬ Upgrading the standard of living
⚬ Space constraints – need fly-over
• How?
⚬ Dolomite = subsidence
⚬ Construction materials
⚬ Foundation; heavy loads
⚬ Grouting: water; stability
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Why Study Geology? Development?
Gauteng (specifically Centurion) has a sinkhole problem!
• Sinkhole, Lyttleton, 2008
• N1 Sinkhole, near R21 interchange, 2022
⚬ Who will pay for this?
⚬ How did it form?
⚬ Could it have been prevented?
H. Labuschagne,
Mybroadband
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Geology for Engineering GLY 256
https://mybroadband.co.za/news/motoring/503900-bad-news-about-n1-sinkhole.html
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Why Study Geology? Development?
Gauteng (specifically Centurion) has a sinkhole problem!
Why?
• Malmani subgroup – DOLOMITES
• When building new roads Sanral first uses “groundpenetrating radar” to scan for dolomite and cavities
• 25% of Gauteng is affected by Dolomite, it is not always
possible to completely steer clear of it.
• https://topauto.co.za/features/68300/all-the-sinkholesyou-see-on-a-10-minute-drive-through-centurion/
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Why Study Geology? Development?
• Construction of the Thukela Dam Scheme, Harrismith, 2009
• Why? Water; Electricity
• How?
⚬ Deep excavations
⚬ Construction materials
⚬ Foundation and basements
⚬ Hydrogeology
The site of this quarry for
materials for the dam wall itself…
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Why Study Geology? Development?
• Construction of the Msikaba Bridge
on the N2 (2020)
• Why?
⚬ Faster travel between KZN and
EC
⚬ Some of the most significant
bridges on the continent being
built
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Why Study Geology? Development?
• Roads:
⚬ Access; transport corridors
• Require:
⚬ Good foundation
⚬ Good materials
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Geotextile, Winburg (2017)
Cut material used as fill, Kranspoort (2016)
Geology for Engineering
GLY (2014)
256 (MA Dippenaar)
Dolerite-Mudrock,
Gariep
Base course, Zeerust (2018)
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Why Study Geology? Energy?
• Energy is also from geological resources
⚬ Fossil fuels such as coal
⚬ Fossil fuels such as gas (hydraulic fracturing; etc.) and oil
⚬ Uranium for nuclear energy
⚬ Geothermal energy (use of geothermal gradient and/ or actual heated vapour or water)
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Why Study Geology?
Energy?
Shale gas
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Why Study Geology? Survival and Health?
• Cost to environment and future health for
current economic and social benefit
• eMalahleni (2015)
⚬ AMD
⚬ Spontaneous combustion
⚬ Mining-related sinkholes
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• eMalahleni (2015)
• AMD
• Spontaneous
combustion
• Mining-related
sinkholes
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Why Study Geology? Survival and Health?
Water supply
Lower Fountain, Groenkloof Nature
Reserve: 24 000 000 l/day to
Pretoria
Grootfontein, PretoriaBapsfontein: 8 000 000 l/day
to Pretoria
Oranjezicht/ Ou Stadsfontein
Cape Town 2014
water project delivers 2 000 000 liters of
water a day
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GLY 256 Geology for Engineering
Welcome to Earth Part II
Mrs. Adri Deysel
What is Geology
• Geology = Geo (Earth; Greek) + Logos
(knowledge; Greek)
• The scientific study of the Earth including
⚬ Its formation
⚬ Its history
⚬ Its composition
⚬ Its processes
• Work from very small microscopic scale to
regional scale of the movement of
continents
• Work is split between office, field and lab
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Why Study Geology? Mitigate Hazards?
• Geological Hazards
• Climate change
• Volcanic eruptions
• Earthquakes
• Slope failure
• Drought
• Floods
• Subsidence
• Sea-level changes
• Tsunamis
• Reduction of biodiversity – the ultimate disaster?
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https://science.howstuffworks.com/environmental/earth/geology/ring-of-fire.htm
Why Study Geology?
Mitigate Hazards?
Earthquakes
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Why Study Geology? Mitigate Hazards?
Santorini, and other Greek islands in the region, are in the middle of an "unprecedented"
seismic swarm or crisis
Santorini lies on the Hellenic Volcanic Arc - a chain of islands created by volcanoes.
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Why Study Geology? Mitigate Hazards?
Tsunamis
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Why Study Geology? Mitigate Hazards?
Tsunami death toll: 162 000
Mosque surrounded by destruction,
Banda Aceh, Indonesia
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More than 700 bodies found from
Khao Lake resort near Phuket
Geology for Engineering GLY 256
Malingee (Indonesia), after all
inhabitants were killed by tsunami.
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Why Study Geology? Mitigate Hazards?
Volcanos
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Hawaii's Kilauea volcano is expected to
erupt any day now and has been
experiencing activity since Dec 2024
For the engineers
• Engineering geologists, hydrogeologists and rock engineers with a scientific
qualification provide scientific data for your use.
• These geologists describe and analyse data that provide information about solid
mechanics, discontinuous mechanics and fluid mechanics.
• Geologists are the source of earth material data that civil engineers, mining
engineers and metallurgical engineers rely on.
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For the engineers
• So see this module as that.
• See that a SACNASP registered geologist and some ECSA registered engineers
carry this function and that the work of scientific data and engineering design
fall under different acts.
• But both need a basic understanding of the other.
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For the engineers
• Scientists rely on engineers to apply their data to design and solve problems.
• What geology provides is necessary for engineers is that we develop in, on and with geological
materials and subsurface water.
• An understanding of geology, minerals, rocks, geological processes and geological maps makes
you a better engineer because you see the function of the geologist and you understand what
they are trying to tell you.
• Laboratories serve to validate geologists’ information, but in the end you are a better engineer if
you understand the data you are given.
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Earth is active in the interior and on surface
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Geological Outcrop
• Outcrop is the rock exposed on or
near surface
• Obviously older rocks underlie
younger rocks, so the “basement”
rocks are mostly obscured by
younger rocks on maps
• That is why geologists need to be
able to interpret threedimensionally
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Diamond et al. (2019). SA Journal of Geology.
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What is Geology
• Earth is old and has been subjected to a vast amount of processes
• Many past processes are mimicked today still
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Marcia Bjornerud (2018) Timefulness.
Princeton
University Press
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Dippenaar)
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Tshwane’s Geological Timeline
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Geological Time
• It is hard to perceive long periods of time
• Earth will very likely continue well beyond humankind’s habitation
Entity
Life expectancy (years)
Limiting processes
Solar system
10 billion
Sun enters red giant phase, engulfs planets
Total habitable time for Earth
Ca. 5.5 billion (ca. 1.7 billion left)
Began at close of heavy meteorite bombardment ca. 3.8 billion year ago; will
end when Sun is so hot that water is boiled from Earth surface
Shield areas of continents
< 4 billion
Erosion
Ocean basin
170 million
Subduction
Mountain belt (topographic)
50-100 million
Relative rates of tectonics and erosion
Typical marine invertebrate species
Fossil record: 10 million
Current species: 100 000
Sea level variation; climate change
Climate change; ocean acidification and anoxia
Typical land vertebrate species
Fossil record: 1 million
Current species: 10 000
Climate change
Climate change; overhunting; habitat destruction
Marcia Bjornerud (2018) Timefulness.
Princeton University Press
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Geological Time
Geological Time
• Extinction is part of the
geological history
• But it is being accelerated by
anthropogenic influence
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Marcia Bjornerud (2018) Timefulness.
Princeton University Press
Why Study Geology?
• We have an enormous footprint on the planet
• We use the geological resources (commodities or materials), we develop on it (foundations), and we are
subjected to its processes (internal and external)
• Resources are scarce, and becoming even scarcer through overuse, pollution, neglect, and ignorance of
science and its solutions
• Environmental protection depends on its wise use: any development is at an environmental cost, so to what
extent can we keep on developing without any regard for the planet?
• As an ENGINEER: you will work with geology (I work with engineers a lot)
• You need to understand how (mining-, engineering- hydro-, exploration-) GEOLOGISTS think
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Introduction to Geology GLY 155
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https://www.geolsoc.org.uk
The Pursuit of Science
• Science entails the “systematic study of the structure and behaviour of the physical and natural world
through observation and experiment”
⚬ I.e. science is provable and proofs can be replicated
• Scientific Research involves exactly these methods of:
⚬ regular, repeatable and exact observations,
⚬ measurements
⚬ repeatable experiments
⚬ logical explanation of observed phenomena and
⚬ predictions
• … which are used to make new discoveries and confirm old ones
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The Pursuit of Science
• The observations and experiments lead to Scientific Hypotheses, namely the tentative explanation for any
occurring natural phenomena
• Hypotheses must be tested by repeated observations, experiments and predictions, in order to gain
credibility
• However, they remain uncertain and may be proven wrong by new data or by wrong predictions
• Examples:
⚬ “The burning of fossil fuels causes global warming”
⚬ “The continents move relatively to each other”
⚬ “Earth is billions of years old”
• Scientific hypotheses may be controversial or widely accepted
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The Pursuit of Science
• A set of hypotheses supporting each other builds a Scientific Theory
• Theories must
⚬ survive repeated challenging and testing
⚬ be supported by large sets of data, and
⚬ explain larger, coherent natural phenomena
• E.g.
⚬ Theory of Plate Tectonics/ Expanding Earth?
⚬ Theory that Earth is near-spherical (doubting it doesn’t make it less true)
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The Pursuit of Science
• Scientific hypotheses and theories must be testable and obey Natural Laws
⚬ E.g. like Newton’s physical Law of Gravity or the Laws of Conservation of Energy, etc.
• Natural laws are regarded as universal truth and are supported by evidence and experience, and by correct
predictions
• Natural laws are irrefutable
• However, in Science, nothing is really completely proven and even laws can be complemented, altered and
corrected, e.g. Newton’s Law of Gravity by Einstein’s theory of relativity
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The Pursuit of Science
• Scientific models are calculations, which are based on hypotheses and theories, explaining and predicting
how natural processes operate
• Models are tested against new observations and measurements and are improved by inclusion of new data,
hypotheses, theories, or are discarded
• In Geology models are often 4-dimensional (spatial and temporal)
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Why Geology?
• Everything we do from now on contributes to or is based on the geological scientific model!
• As engineers, you will likely be dependent on the input of a geologist as some geologists
⚬ … provide insight into the value and extent of mineral deposits
⚬ … supply important information about the stability of ground and slopes
⚬ … evaluate the suitability and extent of materials for construction
⚬ … advise on hydraulic properties of subsurface water for either use or to be removed
⚬ … evaluate groundwater quality and its effect on various receptors
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Why Geology?
• Any development requires different levels of input:
⚬ Geologists provide the natural condition and its properties on which the engineers base their designs
⚬ Engineers provide input (for materials; foundations; etc.) for which the geologist should provide data
• As geologists should be subjected to the principles of engineering, the same applies vice versa
• In order to appreciate geological input, you as engineer should know the:
⚬ Broad history of the Earth (formation)
⚬ Basic composition of the Earth (mineralogy and petrology)
⚬ Most important internal processes and their hazards (deformation; volcanism; seismicity; etc.)
⚬ Most important external processes and their hazards (mass movement; water interactions; etc.)
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