roperties of Logical Systems: Logical systems can have properties of consistency, validity, completeness and soundness. Consistency: this means that no theorem of the system contradicts another. Validity: this means that the system’s rules of proof will never allow a false inference from true premises. Completeness: this means that if a theorem is true, it can be proven. Soundness: which means that the premises are true and the argument is valid

1. CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
reasons that enforce us to conduct this metamorphic terrain mapping are:-
I. To complete the study of metamorphic petrology in addition to class lecture and
laboratory study.
II. From the academic aspect, metamorphic rocks are very important , for example
 the metamorphism processes has great role in the formation and revolution of
continental crust.
 most of mountain chains contain metamorphic rocks,
III. From economic point of view, it is characterized by mineral and ore deposit that are
formed during and after metamorphism process.

2. 1.2 DESCRIPTION OF THE STUDY AREA
1.2.1 Location
The study area is located in southern Ethiopia in Konso
woreda.
It is geographically bounded between 0594000-0599000N
and 0319000-0324000E covering an area of about25 km
square.
1.2.2 Accessibility
 The study area is basically accessed through the Arba
Minch –Konso-Jinka main asphaltroad.Individual traverses
are accessed through the available foot paths.

3. 1.2.3 Physiography and Relief
The study area is characterized by different topographic features such as
flat, gentle slope,steep slopes and other land forms with different
elevation.
The topography of the area is mainly controlled by river cuts.
1.2.4 Drainage pattern and Climate
Drainage patterns are controlled by topography of the land.
Most of drainages of the study area are seasonal streams and the flow of
the streams, tributaries and main rivers are from high to low
topography.
The type of drainage pattern is dendritic.
The area is characterized by sub-tropical dry and hot climate with
average annualtemperature of 23.950 C.

4. 1.2.5 Land use
 The people depend more upon the agriculture for
means of existence.
The land is more privately owned by the local
farmers.
The climate of area is optimal for plant growth but
vegetation cover of the area is too little.
 This is because of the inconsistence nature of the
rock or the soil that has not been developed well in the
vicinity

5. 1.3 Objectives of the study
1.3.1 Main objective
The main objective of this field work is producing the geological map of sorobo area on the scale
of 1:25,000.
1.3.2 Specific objective
The specific objectives of this field work are to:
 Identify and describe the different rock units exposed in the studyarea.
 Identify the different geological structures foundin the study area.
 Understand metamorphic and deformation history of the study area.
 Observe and study alterations and mineralizations (if any).
 Identify the economic importance of the different rock units of the
study area

6. 1.4 SCOPE AND LIMITATION
The area is studied by driving along roads and
walking traverses along creeks and rivers mapping the
outcropping rock types and structures.
 The present study is limited to field observation
because the thin section analyses, geochemical
analysis is needed to know the major and trace
elemental composition of the whole rock.

7. CHAPTER TWO
METHODOLOGY AND
MATERIALS

8. 2.1METHODOLOGY
•In order to achieve the objectives of the field work,
various methodologies have been conducted.
• These various activities are generally grouped into
three phases depending on the order of time and
sequences. These are: pre-field, during field and post
field phases.

9. 2.1.1 Phase I- Pre-field work
•In pre-field phases different preparations including detail
reading the regional geology of konso area, collection of base
maps (topo map), field instruments like GPS, geological
hammer, compass, camera, sample bag, note book, plaster,
color pencil and secondary data have been collected before
conduction of field works.

10. 2.1.2 Phase-II- During field work
•During the field work, road geology method and the
conventional descriptive traversing methods were used
to identify and describe the different outcropped rock
units and the geological structures developed on these
rocks.

11. Road Geology Method
•By the use of road geology traversing method; the
general geology of the overall study area is studied,
important rock units which are exposed in different
parts of the area were described, important and main
geological structures were observed and measured.
•This method is conducted for three days.

12. Traversing Method
• It is used for detail identification of the different rocks and geological structures of the
study area. It is the second method of field investigation in which the local geological
mapping has been conducted by dividing the area into six traverses.
• For each of the traverses various stations were taken at which reading of the geographical
coordinate and elevation from GPS (in order to locate the station on the topographic map).
Description of the rocks have been done based on color (for both fresh and weathered),
texture, mineralogical composition, exposure type, rate of weathering, grade of
metamorphism, etc at outcrop and hand specimen levels. In this method collection of
representative samples (which helps for further laboratory study), observing and measuring
of the orientation of geological structures also have been done. We also collected
photographs showing the exposure of rocks and geological structures.
• Finally by using mineral composition, texture, color and grain size, and others listed above
the lithology is named (for example; Granulite, etc.).

13. 2.1.3 Phase-III- Post field work
•In this phase, the collected data about the rock units,
geological structures and topographic features are compiled
and the general report is written by using computer.
•The overall lithological, drainage, accessibility maps are also
prepared using ArcGIS software. Lastly, these all have been
combined together to produce the final report.

14. 2.2MATERIALS
•The materials used in thisfield work include:
topographic map, map case, GPS (Geographical
positioning system), Bruntoncompass, geological
hammer, sample bag, digital camera, color pencils,
plaster and marker.

15. • Map case :is used to protect topographic map from rain, sweat and hold the map properly.
• Topographic map: is a base map showing in detail ground relief , drainage ,etc
• GPS : is used to locate different geological features and measuring elevation.
• Brunton compass :is an instrument used for determining directions and orientation of
geological Structures(faults and joints) and the nature of the structures (dip direction,
dipamount,and strike directions).
• Geological hammer :is a tool used for breaking samples and it can also serve as scale.
• Sample bag: is used to collect samples after they are cut and labeled.
• Digital camera: is used for taking pictures of different outcrops, rock units and structures.
• Color pencils :are used for mapping in the field to plot geological structures, contacts and
are used in making of map for shading different colors.
• Plaster and marker :are used for labeling samples before they put in to sample bag.
• Note book: is used for writing the necessary note.

16. CHAPTER THREE
REGIONAL GEOLOGYAND TECTONIC SETTING
3.1 INTRODUCTION
The Pan-African Orogeny in the north-east Africa consists of two major terrains:
 The Arabian Nubian Shield and
 Mozambique Belt.
 The polycyclic Proterozoic Mozambique mobile belt, a major geotectonic unit with
a dominant northerly structural trend, extends for some 5000 km along the eastern
margin of the African Precambrian shields.
 A bifurcation in southern Ethiopia separates a north eastern branch, extending from
southern Kenya into the Horn of Africa and southern Arabia.
 The two branches, composed mainly of poly-metamorphic continental lithosphere,
are separated by the Adola belt, comprising crust of fundamentally different origin.

17. Conti…
The ANS is an accretionary terrane of juvenile material (volcanic and volcano-
sedimentary rocks) with dominantly subduction-related magmatism.
The MB involved more recycling of older crustal material (gneisses and migmatites)
and dominantly post-collisional magmatism.
Precambrian metamorphic exposed in the northern, western, southern and eastern
parts of the country .
have a fundamentally important tectonic position in that they occupy the interface
between the MB with predominantly reworked older crust in the south and the
Arabian Nubian Shield (ANS) with abundant ophiolite fragments in the northern
Africa.
The term East African Orogeny (EAO) to encompass both the MB and ANS.
The Precambrian rocks are dominantly north-trending linear belts of low- grade
volcano sedimentary rocks and mafic ultramafic rocks, sandwiched between medium-
to high- grade gneisses and migmatites.

18. Conti…
The high-grade gneisses and migmatites are Lower Complex which is part of the
Mozambique Orogenic Belt consist of amphibolite facies .
The blocks of gneissic terrains which are older than the volcano sedimentary belts
that consist of high grade heterogeneous orthogenisses and paragneisses.
The Arabia-Nubian shield (ANS), northern part of the east Africa orogeny (EAO),is
developed through horizontal crustal accretion during the closure of the Mozambique
ocean.
The Mozambique Belt of Kenya, unlike the Arabian Nubian Shield, lacks evidence of
repeated opening and closure of ocean basins during the East African Orogen, and the
volume of Mozambique Belt gneisses in the Precambrian of southern Ethiopia are
much less than the other.

19. Cont…
3.2 THE GEOLOGY OF THE PRECAMBRIAN BASEMENT ROCKS OF
SOUTHERN ETHIOPIA
oThe Precambrian of southern Ethiopia occupies an important position within the Pan-
African Mozambique Belt and the Arabian–Nubian Shield, which together, form the
East African Orogeny.
oIn the Mozambique belt of Southern Ethiopia, three major divisions;
Lower,
Middle and
Upper Complexes
oThese three complex are differentiated by characteristic contrasts in
lithology,
metamorphism and
structural style.

20. Conti…
The Konso gneiss was initially interpreted as the lowest litho-stratigraphic unit in the
Lower Complex because of its similarity to relict high-grade Archean terrains in the
Ugandan basement.
But represents a localized geothermal peak of the culminatory Mozambique an
metamorphism whose isograds-transgressively overprint the primary layering.
 It is overlain by the more variable Awata gneiss mainly consisting of mafic gneiss
with pelitic and psammitic units, and banded magnetite quartzite.
Tectonised lenses of talc-tremolite schist within the mafic gneisses represent a
disrupted ultramafic unit.
The high-grade gneisses of the Lower Complex in southern Ethiopia core broad
domal structures presumably formed by the reworking of an older E-W trending fold
system during the main Mozambique and deformation which produced N-S structures.

21. Conti…
The position of the Burji gneiss consisting predominantly of finely foliated pelitic and
semi-pelitic schists with minor meta-arkosic and quartzitic facies is problematical.
The uppermost unit of the Lower Complex, contrasts in lithology, intensity of
metamorphism, and migmatisation, as well as structural characteristics suggest that it
may belong to the succeeding Middle Complex, although tectonic contacts render its
relative stratigraphic position uncertain.
Overlying the gneisses of the Lower Complex is the Wadera group, a sequence of
continentally derived meta-arkoses and quartzites.
The Wadera group contains sub-ordinate intercalations of marble, meta-calcareous
rocks and amphibolite, whilst biotite, quartz-muscovite schist and para-amphibolite
feature prominently in the upper part of the sequence.

22. Conti…
The Yabello gneiss also consists of quartzo-feldspathic elastics and is lithologically
indistinguishable from the Wadera group.
 It was formerly placed separately in the Lower Complex by Kasmin, possibly
because of its association with and lateral transition into gneissic granitoid facies.
 Warden (1981) suggests that owing to the in similar position in the litho-stratigraphic
sequence and identical lithology, the Wadera and Yabello gneiss should be regarded as
the same unit .
The Wadera group, which retains a variety of common primary sedimentary
structures, and the Yabello gneiss, constitute a cover rock sequence which is strongly
deformed and metamorphosed.
Sedimentation also overlapped into fault bounded zones within the Adola belt where
Wadera elastics possibly underlie than Adola group.
The Adola group represents the lowest unit within the Upper Complex according to
Kasmin's (1972) classification.

23. Conti…
3.3 TECTONIC SETTING OF THE PRECAMBRIAN ROCKS OF
SOUTHERN ETHIOPIA
The Mozambique belt is exclusively a collision belt that extends along and underlies
the eastern margin of much of the African continent .
It is characterized by folds and metamorphic fabrics that trend between NNE and
NNW and consists of high grade amphibole to granulite facies rock.
 In Ethiopia, the Mozambique Belt is exposed in the south and south-west and forms a
front with the ANS, a lower grade (green schist facies) calc-alkaline volcano
sedimentary terrain to the north.
The evolution of the south-western metamorphic terrain forms part of the whole
evolution of the Precambrian of Ethiopia, which involved early rifting that gave way
to an ocean basin.
Compression resulted in a west-dipping subduction zone and associated volcanic arcs.

24. Cont…
The formation of the gneissic-granulites complex is considered to have involved
periodic closure of the inter-arc basins through subduction uplift and Himalayan type
continental collision and associated metamorphism followed by retrogression at -650-
450 Ma.
Emplacement of plutonic suites started prior or subsequent to the first metamorphic
event some (syn-tectonic plutons) and possible continued event some tens of millions
of year after the closing stages of collision (post-tectonic plutons).
The hammer domain, which corresponds to the eastern sector of the south-western
metamorphic terrain of Ethiopia, contains two major rock groups an older gneiss
complex and several generation of plutonic suites.

26. CHAPTER FOUR
LOCAL GEOLOGY AND GEOLOGICAL
STRUCTURES
4.1 GEOLOGY OF THE STUDY AREA
The area comprises both metamorphic rocks and igneous rocks that are exposed
at different exposures like:
river cut,
road cut,
eroded surface and
hill sides.
The mappable rock units of the study area are
amphibole gneiss,
granulate,
aphanitic basalt (which is igneous rock unit) and
Amphibolite is the only unmappable rock unit of the
study area.

27. 4.1.1 Amphibole gneiss
 Is exposed along the
stream cut,
road cut and
 eroded surfaces.
 It is characterized by
black and white fresh color and
 grey weathered color,
coarse in grain size,
foliated textures and
high rate of weathering with onion shape.
The presence of onion shape type of weathering and black color of this
rock unit suggests that the parent rock of this lithology is basic igneous
rock.
 Coarse grain size also suggests as it is high grade metamorphic rock.

28. The area is highly affected by
 ductile deformation and
 discordant intrusion like dyke.
 This rock unit is dominantly exposed at the study area relative to the other
lithologies.
 This rock unit is characterized by foliation structures which are developed
through parallel preferred arrangement of minerals .
 It has alternative banding sequence of light colored minerals like quartz and
plagioclase feldspars and dark colored ones mainly amphibole minerals.
 The orientation of the foliation and bedding of this rock unit lie in the range of
N10-20E.

29. 4.1.2 Granulite
Exposed at stream cut of the deeper part when the amphibolite gneiss
is removed due to erosion.
 Characterized by
 black fresh color,
 non-foliated (that is granulose) texture and
 coarse grain size.
 It is not affected by weathering effect because of its hardness.
 Mineralogically, it is composed of major mineral like amphibole,
pyroxene, quartz and accessory minerals like garnet.
 The presence of garnet mineral shows that this rock unit is high grade
metamorphic rock
 The parent rock of this rock unit is basic igneous rock.

30. Figure: Field photograph showing granulite rock.

31. 4.1.3 Amphibolite
 Exposed at stream cut of Kayle river.
 Characterized by
 black fresh color and
 grey weathered color,
 non-foliated texture,
 coarse grain size and
 high rate of weathering.
 Amphibole is the dominant mineral, but quartz and feldspars are
found in it sparsely.
 It is medium to high grade metamorphic rock and basic igneous rock
is its parent material
 The rock is found dominantly in contact with amphibole gneiss rock
unit outcrop and not mappable
 It is the least abundant rock unit exposed in the study area relative to
the others.

32. 4.1.4 Aphanitic basalt
 It is the only igneous rock unit found in the study area
 The rock is characterized by
 black fresh color and
 light grey weathered color,
 aphanitic texture and
 fine grain size.
 The rock is highly fragmented due to high weathering
effect.
 The mineral composition are not observed due to grain size.
 But, the black color indicates that it is mafic in
composition.
 The fine grain size also suggests that it is extrusive in origin.

33. 4.2 GEOLOGICAL STRUCTURES IN THE
STUDY AREA
 The area is characterized by containing different
geological structures such as
folds,
faults,
joints,
vein and
 dykes that are formed due to
deformation and intrusion effect.
 The detailed description of each of these geological
structures is given below.

34. 4.2.1 Folds
 Formed due to ductile deformation of the country rock.
 Many small scale folds are developed on the amphibole
gneiss due to the effect of such compressive forces which are
applied in both directions.
 Vertical fold, Recumbent fold, and Inclined fold with fold
axis orientation of trend N60E, N30E, N20E and plunge
90,0,25 degrees respectively are observed at different
location.
 S-shape and Z-shape micro folds are also developed on
amphibole gneiss and they are helpful for the indication of
stress direction.

35. 4.2.2 Fault
 Formed when brittle deformation displaces the block of the rocks.
 It is exposed at river cut and formed from pegmatite vein which developed on
the amphibole gneiss of the study area.
 The exposed fault is strike slip fault which is dextral type fault with an
orientation of strike N30E and dip direction 60SE
4.2.3 Joint
 Observed on felsic dyke developed on amphibole gneiss of the study area.
 It is exposed at river cut with an orientation of strike S70E and dip direction
20NE.
 It is one set of joint with an average of 1m of joint space and 2cm of joint
aperture.

36. 4.2.4 Dyke
 formed by an intrusion of material by cross-cutting through rock unit and it
differs compositionally from the country rock.
 Based on their composition, three different types of dykes are observed.
i. felsic dyke,
ii. basaltic dyke and
iii. pegmatite dyke.
 Three of them are developed on amphibole gneiss with an average thickness and
extension of 3m and 15m respectively.
 Whith an average orientation of strike N80E and dip direction of 10SE.
 Three of them are mappable.

37. 4.2.5 Vein
 Formed by the precipitation of minerals within fractures of
the rock.
 Occurred dominantly by intruding the amphibole gneiss
rock unit of the study area.
 The study area contain two types of veins namely
a. Quartzo-feldsphatic and
b. pegmatite veins.
 The former veins dominantly composed of quartz and
plagioclase feldspars; on the other hand the pegmatite vein is
composed quartz, feldspars, mica and others.
 The average thickness and extension of them are 10cm and
10m

38. 4.3 GRADE OF METAMORPHISM
 Systematic spatial distribution of mineral assemblages that
formed during metamorphism in metamorphic terrains
allows delineating mineral zonation, using index minerals
(example, Garnet, amphibole).
 In the field mineral zones marks the first appearance of an
index minerals, For example
 garnet zone is observed in the study area at different
locations.
 The presence of this garnet zone indicates that the study
area is covered by upper amphibolites facies to granulite
facies.

42. CHAPTER FIVE
ECONOMIC IMPORTANCE OF THE ROCKS OF THE STUDY AREA
LOCAL ECONOMIC IMPORTANCE
The local people use the rocks mainly for terracing purpose, for example
people built terraces
quarry site,
to retain the soil from erosion,
construction of gravel road,
collect maximum water along terracing and
control slope stability.
Terraces are the main features of the Konso land scape and the hills are contoured
by the dry stone terraces that could reach at some places up to 3-5 meter high
and up to 5-6 meter high along river .
The dry stone called ‘Paleta’ of the Konso are located on high hills selected for their
defensive advantage.

43. Cont….
They also use rock for building purposes, for example, to build bafita or
rokamade from locally available rocks.
In the area basalt is commonly and widely used for construction of buildings as
an aggregate and building block.
 Crushed basalt is commonly added to many construction works including
asphalt paving and mixed with concrete.
 The metamorphic rocks found at the study area also
hosts some economically important elements like iron.

44. GENERAL ECONOMIC IMPORTANCE
:Amphibole gneisses :- Has been fashioned into attractive cabochon and miscue
(for beads, paper outright and book hands).
Amphibolites: -This rock unites is economically used for common dimension
stone used in
 construction,
paving,
facing stone on the exterior of buildings,
because of its attractive textures, dark color, hardness and polish ability.
It is also quarried and crushed for use as aggregate in highway construction and
as ballast stone in railroad construction.
They are important metamorphic rock that contains giant mineral.

45. Cont…
Basalt: is used for,
construction (example; as building block or in the ground work),
making cobblestones (from columnar basalts)
 an aggregate in construction project.
 Asphalt pavement aggregate,
 railroad basalt,
filter stone in drain fields, and many other purposes.
Basalts is also cut into dimension stone and sometimes polished for uses as floor
tiles, building veneer, monuments and other stone objects.
 On the other hand weathering product of basalt is useful for agricultural
purpose, because it support plant growth.

46. CHAPTER SIX
CONCLUSION AND RECOMMENDATIONS
CONCLUSION
 The study area composed of different mappable metamorphic rock
units like;-
 Amphibole gneiss
 granulite
 unmappable rock unit like amphibolite and
 comprised mappable igneous rock like aphanitic basalt.
 The area is characterized by containing different geological structures
such as; minor folds, faults, joints, vein and dykes.
 The overall orientation of these rocks and structure is N10-20E.

47. Cont…..
Two types of veins were observed in the study area those are;
quartz veins and pegmatite veins
 there are also basaltic and felsic dykes in the area.
The rocks of study area and the presence of garnet minerals indicate
that the area is exposed to medium to high grade metamorphism.
 The rocks found in the study area have various importances for
different purposes for example;
for raw materials in the construction of various engineering structures
(basalt) due to their strength and as hosts for mineralization.

48. RECOMENDATION
The presence of vugs of sulphides in the quartz veins and tourmaline
bracketed together with coarse-grained pegmatite intrusions are good
clue to be alert for the further exploration.
 It is also recommended the academic staffs specially geology
department and other interested organizations or individuals to conduct
their research on the area in detail because there will be economic
mineralization.

49. THANK YOU A LOT FOR MY ATTENTION