Geology and Engineering Geology
Pierre GERARD
Brussels Faculty of Engineering – Academic Year 2016-2017
1
Geology and Engineering Geology
Program
Lectures and Seminars :
Semester I : Weeks 7 - 14 – Wednesday afternoon (1-5 pm) and
Friday Morning (8-12 am)
Classroom:
Wednesday: Verdeyen (building C)
Friday: Verdeyen (building C)
No course notes  Powerpoint on Virtual University of ULB
Please provide name, email address and NetID for VUB and Phylares
students
2
Geology and Engineering Geology
Program
Lectures:
2 main parts:
- Introduction to geology (+/- 10h)
- Engineering geology (+/- 12 h)
Seminars: (+/- 24 h)
Rocks and minerals identification, geological map interpretation,
engineering geology exercises and geophysics
2 written reports
3
Geology and Engineering Geology
Program
Field trip
Possibility to organize a visit of underground research laboratory in
Mol for radioactive waste repository
More details later
References:
Part I
Geology - Basics for engineers. Parriaux A. 2009. CRC Press/Balkema
Understanding Earth. Grotzinger J., Jordan T., Press F. and Siever R. 2007. Ed. Freeman
Parts II
Geological engineering. Gonzalez de Vallejo L. 2011. CRC Press
4
Geology and Engineering Geology
Examination
Seminars : 2 written reports (by group of 2)  December 2015
Oral Exam: Lectures + Seminars : January 2016
Evaluation:
Written reports 2*15 % = 30%
Oral exam on 17th January 2017 on the theory and
rock/minerals identification 35%
Written exam on 17th January 2017 on the exercises
35%
Second session: same weighing between each part; each
written report has to be submitted again only if its mark
is lower than 10/20
5
Introduction
Geology
Geomaterials
Engineering
Engineering
geology
6
Introduction
Geology
Engineering
Engineering
geology
How do rocks and soils form?
How rocks become deformed?
Influence of rock forming processes
on geotechnical properties
Problematic soils
Soil mechanics
Geotechnics
7
Introduction
Example : Worldwide
geologic and geotechnical
hazards
Sinkhole, Guatemala, 2010
Collapse, Florida
Subsidence, California
Landslide, El Salvador, 2001
8
Introduction
Example : Geologic and
geotechnical hazards in Belgium
Slope stability in Mont de l’Enclus
Subsidence in Ghlin
Collapse in Esneux
9
Introduction
Example : Dam
What type of foundations for a dam?
How to ensure the efficiency of a dam?
Best localisation for a dam (with respect to the geologic conditions)?
10
Introduction
Example : Bridge
How to assess that building foundations are geotechnically safe?
11
Geology and Engineering Geology
Learning outcomes
Part I - Geology
• Describe basic geological processes
• Identify main minerals and rocks encountered on Earth surface
Part II – Engineering geology
• Explain how the geologic conditions, the heterogeneity and the behaviour of
geological materials influence some civil engineering applications
• Interpret geological, geotechnical, geophysical and hydrogeological data to
characterize a site and identify geotechnical hazards associated with a civil
engineering project
Tools
• Describe the basic principles of some geophysical methods and their contributions for
geotechnical engineering
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Outline
Part I. Introduction to geology
1. The origin of the Earth and the tectonic plates theory
2. Minerals and rocks
3. Weathering, transport, burial and lithification
4. Stratigraphy
5. Structural geology
6. Geological map
13
Outline
Part II. Engineering Geology
7. Groundwater
8. Problematic soils
9. Civil engineering applications
10. Georesources
14
Outline
Part I. Introduction to geology
1. The origin of the Earth and the tectonic plates theory
2. Minerals and rocks
3. Weathering, transport, burial and lithification
4. Stratigraphy
5. Structural geology
6. Geological map
15
The Origin of Earth
Solar system formation
•
•
Universe is 15 billion years old (Big Bang theory)

1st chemical elements (H, H2, 4He)

Homogeneous composition
Solar System is 4.55 billion years old

Formation of planets by accretion of matter (law of universal attraction)

Much of the Earth was initially molten because of frequent collisions
with other bodies

Creation of new heavier chemical elements (C, O, Si, etc.)

Heterogeneous composition
16
The Origin of Earth
How did Earth evolve from molten material
to a rocky mass and living planet with
continents, oceans and an atmosphere?
17
The Origin of Earth
Earth composition
•
Differentiation of molten matter by gravity, followed by slow cooling over time
•
Formation of solid crust allowing water to exist at the surface
•
Formation of concentric layers with different chemical composition



Denser elements (Fe, Ni)
→ sink to center = CORE
Lighter elements (Si, O)
→ rise to the surface = CRUST
Remaining elements (Mg, Al, Na, Fe) MANTLE
Earth, 1997
18
The Origin of Earth
Earth composition
•
Volatile elements (water vapor, CO2, CO, N2, H2, etc.) released from interior during
differentiation and early volcanism
 Form the atmosphere
 Drop of Earth temperature
 Condensation of water vapour
 Oceans
19
The Origin of Earth
Earth composition
•
Concentric layers with different chemical compositions
•
Today, only outer core and mantle are still liquid enough to allow differentiation
Crust
Mantle
Core
Depth
State
Density
Elements
0-30 km
Solid
d=2.8
O, Si, Al,
Fe
Lithosphere
Upper
Mantle
30-200 km
Solid
d=3.3
O, Mg, Si,
Fe
= MAGMA
Lower
mantle
200-2900
km
Viscous
d=3.4
O, Mg, Si,
Fe
Asthenosphere
Outer
core
2900-5200
km
Liquid
d=11.5
Fe, Ni
Inner
core
5200-6370
km
Solid
d=12
Fe, Ni
20
The Origin of Earth
Earth composition
•
Chemical composition (% by weight)
Whole Earth
(Fe, Si, O)
Earth’s crust
(Si, O)
21
The Origin of Earth
Tectonic plates theory (~1960)
• Earth’s crust crystallizes in different rigid plates
• About 12 large and rigid plates
Source : US Geological Survey
http://pubs.usgs.gov/publications/text/slabs.html
22
The Origin of Earth
Tectonic plates theory (~1960)
• Distinction between continental crust and ocenanic crust
Continental crust

thicker (25-70 km)

less dense (d=2.7)

Si, Al, O
Oceanic crust

thinner (7-10 km)

denser (d=3.3)

Si, O, Mg, Fe
23
The Origin of Earth
Tectonic plates theory
• 3 principles
1.
Rigid plates move horizontally as a result of convection currents in the
viscous mantle
2.
Rigid plates move vertically as a consequence of the isostasy principle
3.
Earth surface constant  If plates are being created somewhere at Earth
surface, they must be being consumed somewhere else
24
The Origin of Earth
Tectonic plates theory
1.
Rigid plates move horizontally as a result of convection currents in the
viscous mantle
• Hot mantle material (= magma) rises, cools and becomes heavier. So sinks
again, etc.  Convection currents
• Rigid plates are in constant motion at rates of a few cm/yr at Earth surface
25
The Origin of Earth
Tectonic plates theory
2. Rigid plates move vertically as a result of the isostasy principle
• Isostasy = Gravitational equilibrium between crust (tectonic plates) and upper
mantle
• The load must remain constant at the compensation face (=lithosphereasthenosphere contact when equilibrium)
• Crust is lighter than upper mantle
Crust
Depth
State
Density
0-30 km
Solid
d=2.8
Lithosphere
Upper
Mantle
30-300 km
Solid
d=3.3
Inner
mantle
200 - 2900 km
Viscous
d=3.4
Asthenosphere
26
The Origin of Earth
Tectonic plates theory
2. Rigid plates move vertically as a
result of the isostasy principle
Lithosphere
Asthenosphere
Compensation face
• If he elevation changes, resulting weight variation
will be compensated by a change in the elevation of
the light rock-heavy rock contact at depth, such that
at the compensation face, the load will remain
unchanged
• But high viscosity of asthenosphere
 very slow equilibrium
 continuous vertical movement of the
rigid plates
• Explain also why the denser oceanic crust is thinner
than the lighther continental crust
27
Parriaux
The Origin of Earth
Tectonic plates theory
2. Rigid plates move vertically as a result of the isostasy principle
• Consequences for engineers of isostasy – Example of UK
 Scotland glaciated during last Ice Age
(over 10 000 yrs ago)
 Increase of load
 Once the ice sheets went away (8 000
yrs old), isostatic rebound (=uplift) of
Scotland started
Rising
 But compensatory effect : Southearn
part of UK sinks (3 mm/yr)
Tynet
Sinking
28
The Origin of Earth
Tectonic plates theory
2. Rigid plates move vertically as a result of the isostasy principle
• Consequences for engineers of isostasy – Example of UK
 Slow sinking movement of London + Strong tides  floods in London
(especially in 1663)
 1981: large pivoting dam constructed on the Thames (Thames flood barrier)
https://www.youtube.com/watch?v=Dvg2asACsG0
29
The Origin of Earth
Tectonic plates theory
3. Earth surface constant
If plates are being created somewhere at Earth surface, they must be being
consumed somewhere else
30
The Origin of Earth
Tectonic plates theory
• Possible horizontal movements between plates
Divergent boundaries
Convergent boundaries
Transform-fault boundaries
31
The Origin of Earth
Tectonic plates theory
• Possible horizontal movements between plates
32
Source : Understanding Earth
32
The Origin of Earth
Tectonic plates theory
1.
Divergence of 2 oceanic plates
• Mid-oceanic ridges
 Divergence of plates where the
magma rises in the convection
currents, generally at the middle of
oceans (mid-oceanic ridges)
 Production of oceanic crust at the center of the ocean by magma
solidification, which explains the oceanic crust composition (heavier
elements (Mg, Fe) coming from the upper mantle)
33
The Origin of Earth
Tectonic plates theory
1.
Divergence of 2 oceanic plates
• Mid-oceanic ridges
 Symmetrical behaviour (creation of oceanic crust on both sides of the
ridges)
 Formation of 2 oceanic crusts, progressively separated when they move
toward the continental crust (2-3 cm/yr in Atlantic; 17 cm/yr in Pacific)
34
The Origin of Earth
Tectonic plates theory
1.
Divergence of 2 oceanic plates
• Mid-oceanic ridges – Symmetrical behaviour
Ages of rocks on seafloor
Blue represents crust
created some 180 million
years ago. Red indicates
oceanic crust created quite
recently on the geologic
time scale
Source : USGS
35
The Origin of Earth
Tectonic plates theory
1.
Divergence of 2 oceanic
plates
• Mid-oceanic ridges
 Large extent (thousands
of km long – 1000 km
width)
Mid-Atlanctic Ridge
36
The Origin of Earth
Tectonic plates theory
1.
Divergence of 2 oceanic plates
• Mid-oceanic ridges
 Submarine volcanic moutain chains at the midoceanic ridges
 Mid-Atlantic ridge emerges onto land in Iceland
http://globalgeology.blogspot.co.uk
http://platetectonics.com
Volcano Hekla - Island
37
The Origin of Earth
Tectonic plates theory
2.
Divergence of 2 continental plates
• Unusual
• Rift valley, graben
• Associated volcanism
• Example: East Africa (Kilimandjaro)
Volcano Kilimandjaro (Kibo) - Tanzania
38
2.
Divergence of 2 continental plates
• Unusual
• Rift valley, graben
• Associated volcanism
• Example: Rhine Graben
(Boulvain)
Tectonic plates theory
https://en.wikipedia.org/wiki/Upper_Rhine_Plain
The Origin of Earth
39
The Origin of Earth
Tectonic plates theory
3.
Convergence of 1 oceanic plate and 1 continental plate
• Most typical case of subduction
• Denser plate (oceanic crust) subducts under continental crust  creation of an
oceanic trench
Oceanic
trench
Continental crust
Oceanic crust
40
The Origin of Earth
Tectonic plates theory
3.
Convergence of 1 oceanic plate and 1 continental plate
• Oceanic crust sinks into mantle, melts and is recycled into magma
 Compensated by production of oceanic crust at mid-oceanic ridges
(3rd principle: « Constant Earth surface »)
• Formation of a belt of moutains: associated volcanism above the continental
crust; earthquakes
41
The Origin of Earth
Tectonic plates theory
3.
Convergence of 1 oceanic plate and 1 continental plate
• Oceanic trench
Example: Andes (South-America)
Pacific
plate
Plaque
Nazca
Mid-Ocean ridge
42
The Origin of Earth
Tectonic plates theory
3.
Convergence of 1 oceanic plate and 1 continental plate
• Associated volcanism
Example: Andes (South-America)
Tunguragua volcanoe, Ecuador
Wilson, 1989
www.cuyabenolodge.com
43
The Origin of Earth
Tectonic plates theory
4.
Convergence of 2 oceanic plates
• Subduction
• Deep-sea trench
• Formation of a chain of volcanoes (or oceanic arc) on oceanic crust
www.ncgeology.com
44
The Origin of Earth
Tectonic plates theory
4.
Convergence of 2 oceanic plates
Aleutian Islands (Alaska)
•
Example: Alaska
45
The Origin of Earth
Tectonic plates theory
4.
Convergence of 2 oceanic plates
Japan
=
oceanic
arc
Pacific
plate
•
Example: Japan
46
The Origin of Earth
Tectonic plates theory
5.
Hotspots
• Mantle anomalously hot compared with the mantle elsewhere
• Magma rises to Earth surface, generally far frome plate boundaries
• If tectonic plate moves  creation of volcanic chain
47
The Origin of Earth
Tectonic plates theory
5.
Hotspots
• Mantle anomalously hot compared with the mantle elsewhere
• Magma rising to Earth surface, generally far from plate boundaries
• If tectonic plate moves  volcanic chain
www.usgs.com
48
The Origin of Earth
Tectonic plates theory
5.
Hotspots
• Example: Hawaï archipelago
www.smithsonianmag.com
49
The Origin of Earth
Tectonic plates theory
6.
Convergence of 2 continental plates
• Collision  crustal thickening
• Formation of high moutains (Himalaya, Alps)
• No volcanoes
50
The Origin of Earth
Himalaya
development
Tectonic plates theory
6.
Convergence of 2 continental plates
• Example: Himalaya
• Slow process (collision of plates for
Himalaya started about 50 My ago)
Indian plate
Indian
midocean
ridge
51
The Origin of Earth
Tectonic plates theory
6.
Convergence of 2 continental plates
• Example: Himalaya
• Slow process (collision of plates for
Himalaya started about 50 My ago)
52
The Origin of Earth
Tectonic plates theory
7.
Transform-fault boundaries
• Plates slide horizontally past each other
• Neither creation or destruction of material
• They offset divergent boundaries, producing zig-zag plate margins
53
The Origin of Earth
Tectonic plates theory
7.
Transform-fault boundaries
• Many transform faults along midocean ridges
• Associated with destructive
earthquakes
54
The Origin of Earth
Tectonic plates theory
7.
Transform-fault boundaries
• Example: San Andrea fault (San
Francisco)
http://en.wikipedia.org/wiki/San_Andreas_Fault
55
The Origin of Earth
Summary
56
The Origin of Earth
Summary
San Andrea
fault
Pacific
African
rift
Old transorm fault
57
The Origin of Earth
Summary
Many geologic features develop through the interactions of plates at their
boundaries: earthquakes ,volcanoes, mountains, rifts…
Earthquake distribution
in the world
 2000
- 2007
 Earthquake
measuring
> 5 on Richter’s scale
58
Source : www.ualberta.ca
Data source : USGS NEIC earthquake catalog
The Origin of Earth
Tectonic plates theory
Reconstruction of plates movement

Geographic matching

Geologic similarities in rock ages
based on fossils

Paleomagnetic reconstruction at
mid-ocean ridge
59
The Origin of Earth
Tectonic plates theory
Reconstruction of plates movement

Cycles of ocean opening and
closing events (Wilson cycle)

One cycle = 400 – 600 My

Single continent = Pangea

Collision of continents  orogeny
60
The Origin of Earth
Reconstruction of plates movement
1. Continental plates split at rift/graben
Example: rift in East Africa
2. Creation of an ocean and formation of
oceanic crusts at mid oceanic ridges
Example: Red sea
3. Oceanic crusts increase
Example: Atlantic ocean
4. Subduction zones  oceanic crusts
decrease
Example: Pacific ocean
5. Closure of ocean and collision of plates
(=orogeny)
Example: Himalaya
6. Pangea
61
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Only 1 continent: Rodinia
62
The Origin of Earth
History Plate motions
ULaval
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
Separation of new continents, opening of an ocean
Laurentia: North America (without Florida) + Scotland + Groenland
Siberia: Siberia
Baltica: Scandinavia + Russia + Poland + North Germany
63
Gondwana
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Closure of Iapetus ocean
 Volcanic arc between Laurentia and Gondwana
64
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Collision between volcanic arc and Laurentia
 Caledonian orogeny (Appalaches formation)
Separation of new microcontinents from Gondwana
65
The Origin of Earth
History Plate motions
ULaval
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
Collision Baltica – Laurentia
 Caledonian orogeny (Scotland, Norway, Groendland, East of Canada)
Closure of Iapetus ocean
Movement to the North of Gondwana
66
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Collision Gondwana – Laurentia/Baltica
67
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Hercynian/Variscan orogeny
 Maroc, Massif central, Vosges, Corsica, Portugal, Galicia,
South Ireland, Black forest
68
The Origin of Earth
History Plate motions
Worldwide consequences of Variscan orogeny
(including Urals and second stage of Appalachian moutains)
www.wikipedia.com
69
The Origin of Earth
History Plate motions
Continents
ULaval
Chain of Moutains
Seas (continental plateau)
Oceans
1 continent: Pangea
70
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
Seas (continental plateau)
Oceans
ULaval
Beginning of fragmentation
71
The Origin of Earth
History Plate motions
Continents
ULaval
Chain of Moutains
Beginning of fragmentation
Seas (continental plateau)
Oceans
Creation of an oceanic ridge between North America
and North Africa
72
The Origin of Earth
History Plate motions
Continents
ULaval
Chain of Moutains
Opening of Atlantic ocean
Seas (continental plateau)
Oceans
Beginning of separation between South America and Africa
73
The Origin of Earth
History Plate motions
Continents
ULaval
Chain of Moutains
Opening of South Atlantic ocean
Seas (continental plateau)
Oceans
Separation of India from Madagascar
74
The Origin of Earth
History Plate motions
Continents
Chain of Moutains
ULaval
Australia began to move northward
Seas (continental plateau) Collision between India and Asia  Himalaya  Alpine orogeny
75
Collision between Africa and Europa Alpes
Oceans
The Origin of Earth
History Plate motions
Alpine orogeny
www.wikipedia.com
76
The Origin of Earth
History Plate motions
Continents
ULaval
Chain of Moutains
Seas (continental plateau)
Oceans
77
The Origin of Earth
History Plate motions
Alpine orogeny Hercynian orogeny Caledonian orogeny
78
The Origin of Earth
History Plate motions
Atlantic will widen
Collision between Africa and Europa, closing the Mediterranean
Collision between Australia and South East Asia
79
The Origin of Earth
History Plate motions
New subduction zone in Atlantic ocean, near America coasts
 Progressive closure of Atlantic
80
The Origin of Earth
History Plate motions
New Pangea
81