REPUBLIQUE DU CAMEROUN REPUBLIC OF CAMEROON

Paix-Travail-Patrie Peace-Work-Fatherland
******** ********
MINISTERE DES TRAVAUX PUBLICS MINISTRY OF PUBLICS WORKS
******** ********
ECOLE NATIONALE SUPERIEURE DES NATIONAL ADVANCED SCHOOL OF
TRAVAUX PUBLICS PUBLICS WORKS
******** ********
MASTERS EN INGENIERIE MASTERS IN ENGINEERING

Course: GEOLOGY, SISMOLOGY and GEOPHYSICS (CES 301)

GROUP: 12

Explain what you understand by joints, folds and faults. On the

map of Cameroon, show the distribution of Major faults. What
are the roles of the faults on the distribution of rivers and
groundwater occurrence in Cameroon?

 YONG WILLIARD KINCHI 21TP22415

 TINA MADELEINE FABIOLA 21TP22409

 WARDA PETSEK GREGOIRE 21TP22503

 WANG TEMWA RAHISS 21TP22419

 TO-OH VALERY ANKIABOM 21TP22564

 TIMNGUM TELMA NTEIN 21TP22569

 WANG-NKIOH NKUMBE NKENGSONE 21TP22502

 TUMENTA ANDREW NSOSSI 21TP22486

 YONG BENNY HINN 21TP22540

 TERENCE NDZEDZENYUY 21TP22372

 YIMFACK TSAGUE ANDERSON DONALD 21TP22418

 YOBOL MONGO ALPHONSE JUNIOR 21TP22581

 YONG JOEL YONG 21TP22371

 TIEMIOH YVETTE NCHOKIEJEN 21TP22445

 WOUAFO NZONDA ISMAEL 21TP22405

 TONTSA LOIC GASTON 21TP22647

Academic Year:
 TEKAM KUTENG HERWIN DIVINIO 21TP22535 2023 - 2024
 TSAFOR NKENGNI ARMEL 21TP22469

 WATAT TCHATCHOUA WILLIAM FAREL 21TP22618

Teacher: Pr. FANTONG WILSON

1
In geology, joins, folds, and faults are structural features that reflect different
types of stress and deformation in the Earth's crust:

Folds

A fold is a bend or flexure in rocks which initiates a change in amount of dip

and direction of dip. These occur when originally planar rocks are deformed in
a ductile manner, typically under compression, resulting in wavelike bends in
layered rock. The parts of a fold include the hinge (or axis), which is the line of
maximum curvature; the axial plane, which is the surface connecting all the
hinges; and the limbs, which are the sides of the fold. There are different types
of folds, such as anticlines (upward-arching) and synclines (downward-
arching).

Diagram of a simple fold with labels.

Folding is influenced by some factors like;

 Mechanical properties of rocks

 Nature of stress

 Temperature and pressure of environment

 Duration of stress

Types of Folds

2
 There are 3 main types of folds;

1. Anticline folds

This fold arches upward and both sides of the rocks are pushed inwards.
The oldest rock layers are located at the center and the younger ones
towards the edges. E.g Atlas mountain in North Africa.

2. Syncline folds

This fold sinks downwards as both sides of the rocks are pushed
inwards. Here the youngest rock layers are at the center and the older
ones towards the edges. E.g Great syncline in the mountains of
Morocco.

3. Monocline folds

This is a fold whereby the rock layers form an s-shape as the sides of the
rocks are compressed. These are simple steplike folds in otherwise
horizontal sedimentary strata. E.g Uinta mountains in Utah, Colorado

Also, we have domes and basins.

Classification of Folds

i. Based on direction of closure

1. Anticlines

2. Synclines

3. Neutral folds

ii. Based on attitude of axial plane

1. Upright

2. Inclined fold

3. Overturned fold

4. Recumbent fold

iii. Based on curvature of limbs

1. Symmetrical

3
 2. Asymmetrical

3. Overturned

iv. Based on nature of fold profile

1. Parallel or concentric

2. Similar fold

3. Angular fold

4. Box fold

5. Fan fold

6. Drag fold

Joints

These are fractures in rocks where there has been no significant movement
parallel to the surfaces of the fracture. Joints can form due to various reasons,
such as contraction as rocks cool or due to the release of pressure when
overlying rocks are eroded away. Some properties of joints are;

 A series of parallel joints form a system.

 Two or more sets of intersecting joints form a system.

 Two sets of conjugate joints nearly at right angles to one another

produced by the same stress system form conjugate joints

We differentiate 6 types of joints;

1. Shrinkage joints

2. Tectonic sets

3. Strike of longitudinal joints

4. Dip or cross joints

5. Oblique joints

6. Cooling joints

4
Faults

These are fractures in the Earth's crust along which there has been
displacement of the sides relative to one another. Faults are classified based
on the direction of the displacement: dip-slip faults (vertical movement),
strike-slip faults (horizontal movement), and oblique-slip faults (both vertical
and horizontal movement).

Diagram of simple fault with labels.

We differentiate mainly types of faults based on;

Based on Relative movement of fault block

1. Normal fault.

In this fault, hanging wall moves down relative to the footwall due
to shear or tensional forces. Steep dips range from 600 and above.
It is associated with divergent plate boundaries.

E.g East African rift valley.

5
 2. Reverse or Thrust fault

This occurs when the hanging wall moves up relative to the

footwall due to compressional forces. They are associated with
convergent plate boundaries.

E.g Foumban fault in West Cameroon.

3. Strike – slip fault

In this fault, one block of the fault moves horizontally past the
other due to shear forces. When displacement is to the right, it is
described as dextral and when it is to the left it is described as
sinistral. They are associated with transformed plate boundaries.

E.g Central Cameroon Shear Zone (CCSZ) through Foumban, West Cameroon.

6
Distribution of Faults in Cameroon
Geological map of Cameroon showing faulting and shear zones.

7
Faulting in Cameroon is a complex geological process that involves the
movement of the Earth’s crust, resulting in fractures or faults. The country’s
geological structure is influenced by two main features: the Pan-African
Mobile Belt (PMB) in the north and the Congo Craton (CC) in the south.
These structures are characterized by various fault lines, such as the Sanaga
Fault (SF), Central African Shear Zones (CASZ), and the Cameroon Volcanic
Line (CVL), among others.

The Foumban Shear Zone, also known as the Central Cameroon Shear Zone
(CCSZ), is a significant fault zone in Cameroon. It has been correlated with the
Pernambuco fault in northeastern Brazil and is part of the larger CASZ. This
zone dates back to at least 640 million years ago and has been reactivated
several times, including during the opening of the South Atlantic in the
Cretaceous period. The shear zone underlies a chain of active volcanoes
known as the Cameroon Volcanic Line, and seismic activity in the area, such as
the magnitude 5 earthquake near Lake Nyos in 1986, suggests that the shear
zone may be reactivating.

The presence of these fault lines and shear zones has significant implications
for the region, including the potential for earthquakes and volcanic activity.
Additionally, the geological processes associated with faulting can lead to the
formation of mountains, valleys, and other landforms, which can impact the
environment and human activities. Understanding the faulting mechanisms in
Cameroon is crucial for natural resource exploration and disaster risk
management.

Faulting and folding are geological processes that have shaped the landscape
of Cameroon, as they have in many other regions around the world. Cameroon
is located in Central Africa and is characterized by a diverse range of
geological features, including mountains, plateaus, and volcanic formations.

Folding in Cameroon

Folding is another geological process that has influenced the landscape of

Cameroon. Folding occurs when rock layers are subjected to compressional

8
forces, causing them to bend and buckle. In Cameroon, folding has occurred
as a result of tectonic activity associated with the collision of the African and
Eurasian plates. The Cameroon Highlands, located in the western part of the
country, are believed to have been formed through folding processes. These
highlands are characterized by steep slopes and rugged terrain, which are
indicative of the intense tectonic forces that have shaped the region.

Overall, faulting and folding have played important roles in shaping the
geological landscape of Cameroon, contributing to the diversity of its terrain
and the formation of its natural features. These processes continue to be
active today, albeit at a much slower rate, and contribute to the dynamic
nature of the region's geology.

Faulting in Cameroon

Faulting occurs when there is movement along fractures in the Earth's crust,
resulting in the displacement of rock layers. In Cameroon, faulting has played
a significant role in the formation of its landscape, particularly in regions
where there is evidence of tectonic activity. The Cameroon Volcanic Line, for
example, is a prominent geological feature that stretches across the country
from the Gulf of Guinea to the border with Chad. This line is associated with
faulting and volcanic activity, which have contributed to the formation of
volcanic mountains and rift valleys in the region.

The Cameroon Volcanic Line, which extends from the Gulf of Guinea inland, is
a prominent example of this relationship. Along this line, there are numerous
volcanic peaks, including Mount Cameroon, which is the highest mountain in
West Africa. These volcanoes have been formed through a combination of
faulting, magma intrusion, and volcanic eruptions over millions of years.

Faulting has also led to the formation of rift valleys in Cameroon. Rift valleys
occur when the Earth's crust is pulled apart along fault lines, creating

9
elongated depressions in the landscape. The Adamawa Plateau in central
Cameroon is an example of a rift valley that has been formed through tectonic
activity. This plateau is bordered by fault lines and is characterized by its
relatively flat terrain, which contrasts with the surrounding highlands and
mountains.

The presence of fault lines in Cameroon makes the region susceptible to

seismic activity, including earthquakes. While earthquakes in Cameroon are
generally less frequent and intense compared to other seismically active
regions, they can still pose risks to the local population and infrastructure.
Monitoring and understanding fault lines and their associated seismic hazards
are essential for mitigating these risks and ensuring the safety of communities
in Cameroon.

Overall, faulting and folding are fundamental geological processes that have
shaped the landscape and geological history of Cameroon. By studying these
processes, geologists can gain insights into the tectonic evolution of the
region and better understand its geological hazards and natural resources.

Role of Faulting in distribution of Rivers and Groundwater occurrence

Faults play significant roles in the distribution of rivers and groundwater

occurrence in Cameroon due to their impact on the geological structure and
hydrogeological characteristics of the region:

1. Control of River Courses:

- Faults often act as zones of weakness in the Earth's crust, influencing the
paths that rivers follow.

- In Cameroon, faults may create linear depressions or valleys where rivers

flow, guiding their courses across the landscape.

10
 - Fault controlled river courses can result in straight or meandering patterns
depending on the orientation and activity of the faults.

- The Sanaga River and the Sanaga Fault Line are closely intertwined
geological features in Cameroon, and their relationship has influenced the
river's course and characteristics over time. Here are some ways the Sanaga
Fault Line has affected the Sanaga River:

 Topographical Changes: The Sanaga Fault Line is responsible for

creating significant topographical changes in the region. It has caused
uplifts and depressions in the landscape, altering the path the Sanaga
River takes as it flows through the area. These changes can result in the
river meandering or changing its course altogether. For example, the
fault may create a depression that becomes a natural pathway for the
river to flow through.

 Hydrological Features: The fault line can create hydrological features

such as rapids or waterfalls along the Sanaga River. These features occur
where the fault has caused the riverbed to drop abruptly, leading to the
formation of cascades or turbulent stretches of water. One such
example is the Ekom Waterfalls, which are located on the upper course
of the Sanaga River and are believed to be influenced by the geological
activity along the fault line.

 Formation of Lakes and Wetlands: The Sanaga Fault Line can impede the
flow of the Sanaga River in certain areas, leading to the formation of
lakes or wetlands. When the fault creates a barrier, water can
accumulate behind it, forming stagnant or slow-moving bodies of water.
These areas often become habitats for various aquatic species and can
have ecological significance. Lake Ossa, for instance, is a notable lake
formed along the Sanaga River, likely influenced by the geological
activity of the fault line.

11
 Geologic map of Sanaga fault line

Overall, the Sanaga Fault Line plays a significant role in shaping the
characteristics of the Sanaga River and the surrounding region. Its geological
activity influences the river's path, creates distinctive features along its course,
and contributes to the formation of diverse habitats and ecosystems.

2. Formation of Rift Valleys:

- Rift valleys, which are elongated depressions formed by the stretching and
thinning of the Earth's crust along fault lines, can provide conduits for river
systems.

- Faulting along rift zones in Cameroon, such as the Adamawa Plateau, may
create favourable conditions for the formation of rift valleys where rivers flow
and accumulate water.

- The Benue Trough is a major geological feature in central and eastern

Nigeria, extending into northwestern Cameroon.

- It is a rift valley formed by extensional forces along fault lines.

12
 - The Benue River, one of the principal tributaries of the Niger River, flows
through the Benue Trough.

- Faulting along the Benue Trough has created a linear depression that
serves as a conduit for the Benue River, guiding its course through
northwestern Cameroon i.e Mamfe basin and Garoua basin.

- The fault-controlled nature of the Benue Trough influences the drainage

pattern and distribution of water resources in the region.
Map showing Benue trough and it’s relation with Garoua and Mamfe Basins

13
3. Groundwater Occurrence:

- Faults can serve as pathways for the movement of groundwater through

the subsurface.

- In Cameroon, fault zones may create conduits and fractures that allow
groundwater to flow and accumulate in aquifers.

- Fault-related fractures can enhance the permeability of rock formations,

facilitating the recharge and storage of groundwater.

- The Adamawa Plateau in central Cameroon is characterized by faulting

and volcanic activity.

- Faulting has contributed to the formation of rift valleys and structural

depressions within the plateau.

- These fault zones may serve as pathways for groundwater movement and
accumulation.

- Groundwater occurrence in the Adamawa Plateau is influenced by the

presence of fault-related fractures and fault breccias, which create permeable
zones capable of storing groundwater.

- Wells and boreholes drilled in areas associated with fault zones were
intended to tap into these aquifers to access groundwater for domestic and
agricultural use.

The Adamawa Plateau in Cameroon is known for its complex geological

structure, with its fault zones, which affects the success of borehole drilling for
groundwater. A study in the Ngaoundéré area of the Adamawa region
highlighted several challenges and findings related to borehole drilling.

 Borehole Failures: Many boreholes in the region fail due to a lack of

understanding of how lithology and geological structures influence
aquifer productivity. This reasons aren’t completed attributed to the
influence of fault zones but other geological factors.

14
 Geological map showing Adamawa fault zone

4. Aquifer Formation:

- Fault zones can host aquifers, geological formations that contain and
transmit groundwater.

- Fault-related fractures and fault breccias (crushed and fragmented rocks

along fault lines) may create porous and permeable zones capable of storing
significant quantities of groundwater.

- Aquifers associated with fault systems in Cameroon may serve as important

sources of water for domestic, agricultural, and industrial use.

- Adamawa Plateau Aquifer: As earlier mentioned the Adamawa Plateau in

Cameroon is characterized by fault lines and fractures resulting from tectonic
activity. These faults create pathways for water to percolate deep into the
ground, forming aquifers within the fractured rock. Groundwater stored in
these aquifers is an essential water source for both agricultural and domestic
use in the region.

15
 - Central Cameroon Aquifer: In the central part of the country, faulting
associated with the Cameroon Volcanic Line as well as the Central Cameroon
Shear Zone has influenced the formation of aquifers within volcanic rocks and
associated sedimentary deposits. Fault lines and fractures provide pathways
for rainwater infiltration, allowing it to accumulate within porous volcanic
rocks. These aquifers are important for supplying water to communities and
supporting irrigation in agricultural areas.

- Chad Basin Aquifer: While the majority of the Chad Basin lies in
neighbouring countries, Cameroon also shares a portion of this geological
formation. Faulting within the basin has created fractured zones that host
significant groundwater resources too.
Geologic map showing distribution of Aquifers

16
5. Hydrogeological Hazards:

- While faults can enhance groundwater occurrence, they can also pose
hydrogeological hazards.

- Faults may act as barriers or conduits for contaminants, affecting the

quality of groundwater resources.

- Seismic activity along faults can cause ground shaking and ground
displacement, potentially compromising the integrity of wells and other
groundwater infrastructure.

- Mount Cameroon and Hydrogeological Hazards:

- Mount Cameroon is an active volcano located near the coast of

southwestern Cameroon.

- The volcanic edifice is associated with faulting and seismic activity.

- Fault lines around Mount Cameroon may influence the distribution of

groundwater resources.

17
 - However, the region is also prone to hydrogeological hazards associated
with volcanic activity and faulting, such as ground shaking, ground
displacement, and volcanic eruptions.

- These hazards can impact the availability and accessibility of groundwater

and pose risks to communities living in the vicinity of Mount Cameroon (Fako).
Geological map of the Mt Fako area including settlements that could be affected by hazard

These examples illustrate how faults shape the distribution of rivers and
groundwater occurrence in Cameroon, influencing hydrological processes and
posing both opportunities and challenges for water resources management in
the region.

Overall, faults exert a considerable influence on the distribution of rivers and

groundwater occurrence in Cameroon, shaping the hydrological characteristics
of the region and influencing the availability and accessibility of water
resources. Understanding the roles of faults in hydrogeological processes is
essential for effective water resources management and environmental
planning in Cameroon.

18
Source(s)
1. Faults, Folds, and Joints and The Difference Between Them
2. Structural geology | Folds, Faults & Joints | Britannica
3. Geology - Folds, Faults, Strata | Britannica
4. Folds and Faults Study Guide | CK-12 Foundation

19