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7/23/2019 Field Report on Khewra Gorge and It,s Surrounding Areas
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ContentsCERTIFICATE
ACKNOWLWDGEMENT
ABSTRACT
Chapter-1 ............................................................................................................................................ 13
INTRODUCTION ................................................................................................................................. 13
1.1. Aim Of Study: ........................................................................................................................... 13
1.2. Introducton To The Mapped Area ........................................................................................... 13
1.3. Accessability Of The Mapped Area .......................................................................................... 13
1.3.1 The Salt Range .................................................................................................................... 13
1.3.2. Khewra Town .................................................................................................................... 14
1.3.3. Khewra salt Mine .............................................................................................................. 14
1.3.4 .Stay at Choa Saidunshah ................................................................................................... 15
1.3 Inhabitate Of The Assigned Area .............................................................................................. 16
1.4.Previous Work ........................................................................................................................... 16
Chapter- 2........................................................................................................................................... 18
PHYSIOGRAPHY.................................................................................................................................... 18
2.1. Relief.................................................................................................................................... 18
2.2. Climate .................................................................................................................................... 18
2.3.Vegetation Cover .................................................................................................................. 18
2.4. Weathering............................................................................................................................... 19
2.4.1. Mechanical Weathering .................................................................................................... 19
2.4.2.Frost Action ........................................................................................................................ 20
2.4.3. Chemical Weathering ........................................................................................................ 20
2.5. Hydrology ................................................................................................................................. 212.5.1.Ratna Nala .......................................................................................................................... 21
2.6.Stream Load .............................................................................................................................. 22
2.7.Drainage Pattern ....................................................................................................................... 22
2.7.1.Dendritic Drainage Pattern .................................................................................................... 22
2.7.2.Sub Parallel Drainage Pattern ............................................................................................ 22
2.8. Mass Wasting ...................................................................................................................... 22
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2.9. Main Khewra Nala .................................................................................................................... 23
2.9.1.Bifurcaton Ratio Of Main Khewra Nala: ............................................................................. 23
2.10..Choa Saidan Shah Pidh Nala ................................................................................................ 26
2.10.1.Bifurcaton Ratio Of Choa Saidan Shah-Pidh Nala: ........................................................... 26
Chapter- 3........................................................................................................................................... 29
STRATIGRAPHY..................................................................................................................................... 29
3.1 Introduction .............................................................................................................................. 29
STRATIGRAPHIC TABLE OF THE ASSIGNED AREA.......................................................................... 30
Table 3.1: Stratigraphic succession of Eastern Salt Range (Khewra Gorge) ............................... 30
3.2. Stratigraphy .............................................................................................................................. 31
3.2.1 Salt Range Formation ............................................................................................................. 31
3.2.2 Khewra Sandstone ................................................................................................................. 33
3.2.3. Kussak Formation .................................................................................................................. 36
3.2.4. Jutana Formation .................................................................................................................. 38
3.2.5. Baghanwala Formation ......................................................................................................... 40
3.2.6 Tobra Formation .................................................................................................................... 42
3.2.7.Dandot Formation .................................................................................................................. 44
3.2.8. Warchha Sandstone .............................................................................................................. 46
3.2.9. Namal Formation .................................................................................................................. 48
3.2.10 Sakesar Limestone ............................................................................................................... 50
Chapter- 4........................................................................................................................................... 54
SEDIMENTARY STRUCTURES.................................................................................................................. 54
4.1. Cross Bedding:- ........................................................................................................................ 55
4.2. Ripple Marks:- .......................................................................................................................... 56
4.3. Worm Tracks:- .......................................................................................................................... 57
4.4. Nodule Structures: ................................................................................................................... 58
4.5. Salt Pseudomorphs:- ................................................................................................................ 59
4.6. Karen Structures:- .................................................................................................................... 60
Chapter- 5........................................................................................................................................... 61
DEPOSI'I'IONAL ENVIRONMENTS............................................................................................................. 61
5.1. Salt Range Formation ............................................................................................................... 61
5.2. Khewra Sandstone ................................................................................................................... 62
5.3. Kussak Formation ..................................................................................................................... 62
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5.4. Jutana Formation ..................................................................................................................... 63
5.5. Baghanwala Formation ............................................................................................................ 64
5.6. Tobra Formation ...................................................................................................................... 64
5.7. Warcha Sandstone ................................................................................................................... 65
5.8.Namal Formation ...................................................................................................................... 665.9. Sakaser Limestone ................................................................................................................... 66
Chapter- 6........................................................................................................................................... 67
GEOLOGICAL STRUCTURES..................................................................................................................... 67
6.1. Faults: ....................................................................................................................................... 67
6.1.1.Reverse Fault: .................................................................................................................... 67
6.1.2. Normal Fault ..................................................................................................................... 67
6.1.3. Grangul Thrust fault: ......................................................................................................... 67
6.2. Unconformaties: ...................................................................................................................... 67
6.2.1. Disconformity: .................................................................................................................. 68
6.2.2. Permian unconformity ..................................................................................................... 68
6.2.3. Unconformity ................................................................................................................... 68
6.2.4. Pidh Graben...................................................................................................................... 68
Chapter- 7........................................................................................................................................... 69
HYDRO CARBON POTENTIAL OF THE MAPPED AREA.................................................................................. 69
7.1.Introduction .............................................................................................................................. 69
7.2.Energy Resources ...................................................................................................................... 69
7.2.1.Petroleum Play ................................................................................................................... 69
Table 7.1 :Source Rocks ,Reservoir Rocks and Seal Rocks distribution in the Stratigraphy
Column of the Assigned area along with possible timing of hydrocarbon maturation and
Formation of the traps. ............................................................................................................... 70
7.3. Source Rocks ....................................................................................................................... 70
Maturation ............................................................................................................................... 72
Gene ra tio n an d Mi gr at io n ................................................................................................... 72
7.4. Reserv oi r Rocks ..................................................................................................................... 73
Traps and Seal s ........................................................................................................................ 74
Chapter- 8........................................................................................................................................... 75
ECONOMIC GEOLOGY............................................................................................................................. 75
8.1. Introduction ............................................................................................................................. 75
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8.2.Coal ........................................................................................................................................... 75
8.3.Economic Industrial Raw Materials and Minerals .................................................................... 76
8.3.1. Rock Salt ............................................................................................................................ 76
8.3.2. Gypsum ............................................................................................................................. 77
8.3.3. Limestone .......................................................................................................................... 788.3.4. Dolomite............................................................................................................................ 80
8.3.5. Sandstone ......................................................................................................................... 80
Chapter- 9........................................................................................................................................... 82
REFERENCES.......................................................................................................................................... 82
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All Praise To All Mighty ALLAH Who Gave Us Knowledge ,Education And
Learning To Work To The Best Of Our Abilities, Courage And Patience To Obligation .We
Are Able To Complete Our Field Work And Are Eventually Presenting This Field Report. We
Are Thankful To Dr Ibrahim Baloch Chairman ,Geology Department , And Also Our
Supervisor For Organizing The Field Program , Which Was Not Possible Without Him..We
Offer Our Sincere Thanks To Assistant Prof.Mr. Rahum-U-Din, Assistant Prof. Ahmed Shah
Kakar And Last Not Least Assistant Prof. Syed Haroon Ali For Their Supervision In Field And
Gaudiness For Preparation Of This Field Report . We Had Some Difficulties In Doing This
Task ,But They Taught Us Patiently Until We Knew What To Do .
Last But Not Least ,Our Group Who Were Doing This Field Work Sharing Ideas ,Helping
Each Other And We Combined And Discussed Together ,We Had This Task Done.
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A comprehensive geological Map of Khewra Gorge and its surroundings
area Jhelum and Chakwal districts of Punjab Province, Which is prepared on the scale of
1:50000 about 60 square Kilometer area was mapped which was lying on latitude 30o
43/
04//
to 32o
38/
48//
and longitude of 73o
00/
25//
to 72o
59/
21//
and the Toposheet No 43
D/14 of Geological Survey of Pakistan.
This report describes the stratigraphy Structural geology, economic Geology and geological
history of the studied area. The rock units in studied area range from Precambrian to the
Eocene age. The Stratigraphic Succession of the area: Salt Range Formation (Pre-
Cambrian), Khewra Sandstone (Early Cambrian), Kussak Formation (Early Cambrian), Jutana
formation (Middle Cambrian), Baghanwala Formation (Late Cambrian) Tobra formation
(Early Permian) Dandot Formation (Early Permian) Warcha Sandstone (late Permian) Namal
Formation (Early Eocene) and Sakesar Limestone (Early Eocene) Detail study of Stratigraphy
of the area is carried out including the Characters of each rock unit. Shale , Limestone,
Sandstone and marls the major Lithologies of Sedimentary rocks.
These formations were deposits under shallow to moderately deep marine and fluvial and
glacial environments. The assigned area tectonically active and the rocks units thruster
over Punjab plain and highly deformed.
Geological Cross section were prepared for better understanding of the structures of the
assigned area along with their symbols and abbreviations also studied the potential
hydrocarbons of the rocks and economic rocks of the area.
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Chapter-1
INTRODUCTION1.1. Aim Of Study:
The geological Fieldwork and thesis writing is an essential Requirement for Ms.c degree in
Geology .Students of Ms.c (Final) have done field work for three weeks in the Eastern Salt
Range Around Khewra Gorge in the Jhelum Chakwal district of Punjab Province, Which
was carried out In the month of February-March 2012 .
The main purpose of field work was to learn the geological mapping, recognition of the
geological feature ,proper collection of geological data in the field work and with student
point of view they are trained for all sort of geological structures ,tectonics and
stratigraphy of the mapped area observed in field .
1.2. Introducton To The Mapped Area
The area around the vicinity of Khewra gorge to Choa saiden shah (Jhelum district) was our
assigned area, which lies in eastern part of salt range, Pakistan. The area is covered in
Toposheet no 43D/14 of the survey of Pakistan .The location of the salt range is such that
the potwar plateau lies in its north ,Punjab plain is In south ,while in the east and west .it is
bounded by Jhelum and Indus rivers ,respectively.
1.3. Accessability Of The Mapped Area
1.3.1 The Salt Range
Most of the tourists to the Punjab tend to follow the beaten track .they go to well known
places with developed infrastructures of accommodation and other facilities .among the
places ,which one tends to over look ,is Jhelum , the recruiting ground of the former British
Army and now to Pakistan Army .It is also the starting point of the famous salt Range ,a
name given to two lines of low rugged hills and the fertile land sandwiched between them.
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FIG 1.1 Map is showing Location of the Field Area.
1.3.2. Khewra Town
Khewra is a town of Pind Dadan Khan Tehsil in Jhelum District, Punjab province,
Pakistan.the population of Khewra is 1,00.000 and the world second largest salt deposits
are located in Khewra .
1.3.3. Khewra salt Mine
The Khewra salt mine also known as Mayo Salt mine named in the honor of Lord Mayo, who visited
the mine as Viceroy of IndiaThe salt mine is a part of salt range originated about 800 million years
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ago after a shallow sea evaporated and following geological movements salt range
stretched to about 300 kilometers was formed It is said that the salt reserves at Khewra
were discovered when Alexander visited South Asia, coming across the Jhelum and
Mianwali region, during his Indian campaign. The discovery of the mine, however, was not
made by Alexander nor his "allies", but by his horse. It is stated that when Alexander's
army stopped here for rest, the horses started licking the stones. One of his soldiers took
notice of it and when he tasted the rock stone, it was salty thus leading to the discovery of
the salt mine. During Mughal era the salt was made available commercially by exporting it
to different markets including far away region of Central Asia With the downfall of Mughal
empire, the mine was taken over by Sikhs. Hari Singh Nalwa the Sikh ruler shared the
management of mine with the ruler of Jammu and Kashmir, Gulab Singh. The salt quarried
during Sikh rule was not only a source of general consumption but also a source of revenue
After Britishers took over the territory from Sikhs, they developed the mine further in
1872. Britishers found the mining carried out in an inefficient way with irregular and
narrow tunnels, entrances, which made the movement of laborers dangerous and difficult.
The supply of water inside mine was poor and there was no storage facility for the mined
salt. The only road to Khewra mine was a rocky road on difficult terrain. Addressing these
problems the then government leveled the road, built go-downs, provided supply of water,
improved the entrances and tunnels, introduced better mechanism for excavation of salt.
1.3.4 .Stay at Choa Saidunshah
Our stay during the field work was in a small town and Union Council of Chakwal District in
the Punjab Province of Pakistan. It is the one of the seven Union Councils of Choa Saidan
Shah Tehsil
This town is named after the saint Saidan Shah Shirazi. The legend goes that the area was a
desert until the holy man arrived, when he struck the ground with his staff and sweet
water sprang up ("Choa" means "spring"). The saints shrine is set back from the main
bazaar in a courtyard, and the annual urs is held in April.
Choa Saidan Shah is located in the south of Chakwal about 35 kilometres (22 mi) from the
town centre on the Chakwal-Khewra road, in the east of Kallar Kahar, about 27 kilometres
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(17 mi) from the M2 motorway, about 10 kilometres (6 mi) north of Khewra and about 6
kilometres (4 mi) from Katas.The town is placed in a bowl shaped valley, surrounded by
hills. It is surrounded by trees and orchards, and is famous for its roses and perfumes.
1.3 Inhabitate Of The Assigned Area
The study area false administratively within Jhelum-chakwal District and most of its
population live in small towns Khewra .Tobar Village Choa Saidanshah,Dandot Village and
Pidh village are the major localities where most of the population of mapped area
habitats.khewra and choa Saidanshah are generally more populated . All agricultural
activities are confined to the big plains which run parallel in between the mountains .
Rain water is generally used for irrigation in addition to tube wells,which are also the
major source of irrigation particularly in valleys and depressions.
1.4.Previous Work
In the past the salt Range has attracted geologists from all over the world to study
Cambrian Stratigraphy .the Permian Triassic boundary,and Lower Territary foraminiferal
biostratigraphy .Particular note is the pioneering work of E.E.GEE(1935,1945) ,who
dedicated almost his entire geological career to study of the Salt Range .His initial work
related to solving the controversy regarding the age of the Saline Series,a burning Topicof that time ,and he made a great contribution by producing a geological map (more
recently six sheets on a scale 1:50,000 have been published by the Geological Survey of
Pakistan excluding the Trans-Indus Surghar Range).
DAVIES and PINFOLD (1937) completed a comprehensive study of Lower Teritary Larger
foraminifera of the Salt Range.WAAGEN (1882-1885,1895) worked on the brachiopods of
the permian of the Salt Range and FATIMI (1973) studied the ceratitids of the Triassic of
the Salt Range and Trans-Indus Surghar Range.He also worked on stratigraphic
nomenclature on the Salt Range as did SHAH (1977).KUMMEL and TELCHERT (1966,1970)
illustrated Permian brachiopods and described the detailed stratigraphy of the Permian
rocks while GRANT (1966)described trilobites.HAQUE (1956) described the amaller
foraminifera from the Teritiary formations of the western Namal Gorge ,Salt Range .AFZAL
(1997) completed his doctoral thesis on the planktonic foraminifera of the paleogene and
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established a planktonic biostratigraphy for the patala formation of the Salt Range and
Surgher Range (AFZAL and VON DANIELS ,1991;AFZAL and BUTT ,2000). SAMEENI(1997)
completed his doctoral thesis on paleogene biostratigraphy of the Salt Range under
UNESCO IGCP-286 , headed by Prof .Lukas HOTTINGER o Basal University , Switzerland ,and
established an alveolinid biostratigraphy for the Eocene succession of the Salt Range
(SAMENI and BUTT ,1996,2004;SAMEENI and HOTTINGER , 2003).
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Chapter- 2
PHYSIOGRAPHY
2.1. Relief
The Mapped Area lies between the Eastern Plateau in southeast and the Potwar
Plateau in north. The highest elevation from sea level is 3687 feet and is called
Tobra Peak . . The lowest elevation from sea level is I500 near Khewra town in south
of the Mapped Area. Thus the absolute reliefis 1987 feet.
2.2. Climate
The Mapped Area lies within the semi arid region. The local climate is more towards the
humid because the area experienced more rainfall than the adjacent areas of
Potwar, Kussak and Khewra.
Thick cover of vegetation reduces the intensity of hot summers. The altitude has
significant effect which produced precipitous slopes against the Monsoons.
2.3. Vegetation Cover
Dense vegetation cover conceals the geology of certain parts of the area .Two rakhs
(jungles) are present in the Project area These are Rak.h Karangal and Rak.h
Drengan. These rakhs presented serious difficulties in traversing and geological studies.
In Southern part, the south facing slopes are generally warmer than adjacent north facing
slopes due to direct fall of sunrays. At lower latitudes these sunny slopes are unable to
preserve moisture content. The nearby north facing slopes retain moisture content and
hence better vegetation cover is there. (Plants and Ecosystems by W.D. Billing).
The names of various herbs, shrubs and trees present in the area are as follow:
Oleacuspidata (Kaoo)
Acacia modesta (Phulai) Acacia arabica (Kiker)
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Capparis dicidua (Kundair) Dodonea viscosa (Snutha) Ipomea viscosa (Bhaikar) Gnmda Saghar Dhaman Gogair
2.4. Weathering
Weathering is the total effect of all the various sub aerial processes that cooperate in
bringing about the decay and disintegration of the rocks. Weathering of rocks depends
upon following factors:
Mineral composition and structure of the rock Climatic conditions Presence and absence of vegetation Topography of the area Weathering is of three types Mechanical or Physical Weathering Chemical Weathering Biological Weathering
2.4.1. Mechanical Weathering
Mechanical changes may be brought about by changes in the temperature of the rock body
itself or it may be due to the Formation of ice within the interstices or within the joints of
the rock.
mechanical weathering break up rocks into smaller and smaller fragments by physical
forces without involving appreciable chemical decomposition.
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In the Mapped Area following processes of mechanical weathering could be observed.
2.4.2.Frost Action
Mechanical disintegration of rocks depends to a large degree upon the presence of water
in the interstices or joints. Rocks are disintegrated by repeated freezing and thawing of
water in these joints and voids etc.
Water fills the crevices and joints present in the rocks, on fall of temperature it freezes and
expands because of increase in volume. This volume increase exerts a lot of pressure upon
the sides of joints and voids. Repeated freezing and thawing resulted in the shattering of
rock into angular fragments. These angular fragments can be seen on the slopes formed by
sandstone and limestone etc, in Tobra upper portion of gorge and Pind saiden shah.
2.4.3. Chemical Weathering
The Mapped Area is predominantly covered by Sakaser Limestone ,Khewra sand stone
,salt range Formation ,Namal and Warcha .Main type of chemical weathering active in
these carbonate rocks is solution weathering.
Rain water with dissolved carbon dioxide together with humus acid from the surface of
rocks attacks the carbonate rocks and removes them in the form of solution.
Following evidences of solution weathering are reported from the Mapped Area.
Karen structuresMiniature ridges formed on the surface of Sakesar Limestone.Karen structures are
also present in salt of salt range Formation.
Solution cavitiesSolution cavities in the Sakesar Limestone exposed and Namal Formation.
Widened jointsIn Sakesar Limestone, Khewra sand stone ,warcha sand stone and Jutana Formation, joints
are widened due to solutioning.
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Honey comb weatheringIt is present in Khewra sand stone in Khewra Gorge..
Plant WedgingWith the growth of plants and their roots, joints and crevices are extended due to which
rocks become loose. Plant wedging effect in the Mapped Area is noted from roots of
banyan tree.
2.5. Hydrology
The area is drained by two permanent and a lot of aphermal streams. Permanent source of
water are springs of fresh water suggesting shallow reservoir rocks.
The parental streams are;
2.5.1.Ratna Nala
A Nala flowing in front of Karangal Ridge between the "Sarai" and Karangal Peak (3511).
Springs are the permanent source of water. All the streams reduced in volume during
winter. Springs were observed in Ratna Nala.
Numerous wells have been dug through the Wahali valley and Basharat area to
irrigate cultivated land. Ground water level is very low during dry season. A number of
water ponds are present. Rainwater is stored by building small bunds around the ponds.
All the streams of the Mapped Area drain into "Kus Surar" which joins the River
Bunha. Karangal Ridge extending north or northeast, Wahali Section extending eastwest
and Chail Ridge striking northeast act as water divide.
Locals have built protective bunds to save their cultivated land from erosion in rainy
seasons.
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2.6.Stream Load
The load carried by streams at higher altitude is composed of large boulders and angular
fragments of rocks whereas in main streams at lower level, the load mainly is pebbles, gravels and
silty sand etc.
2.7.Drainage Pattern
In the Mapped Area, two types of drainage pattern have been observed. Dendritic drainage pattern
developed in northeastern half of the area. Fig 2.1
Subparallel drainage pattern developed on the dip slopes of Sakaser Limestone around the
saidan shah and pidh area . Fig 2.1
2.7.1.Dendritic Drainage Pattern
This type of drainage pattern is characterized by irregular branching of the tributaries in
many directions and at almost any angle usually less than right angle. This type of drainage
pattern is developed on the rocks of uniform resistance and structurally non controlled
rocks.
In the Mapped Area special dendritic pattern, the pinnate drainage pattern is observed.
The tributaries are sub parallel to the main stream and join it at acute angles. This
effect is particularly due to steep slopes on which the tributaries developed streams inKarangal area and Choa Ganj Ali Shah area.
2.7.2.Sub Parallel Drainage Pattern
Sub parallel drainage pattern is an intermediate type between dendritic and parallel drainage
patterns. It may develop on steep slopes because run off find the shortest line in parallel
streamlets, perpendicular to the strike of scarp. Nearly parallel tributaries join the main stream at
an angle.
In Wahali Section ofthe Mapped Area, the streams flowing at ihe dip slope ofSakaser Limestone
exhibit this type of drainage pattern.
2.8. Mass Wasting
Due to effect of physical and chemical weathering rocks become weak and produce loose
material. The down slope movement of loose material purely under gravity is termed as
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mass wasting. The results of following processes of mass wasting were observed in the
area.This mass wasting is well observed in salt range Formation.
Rock CreepThe down slope movement of the individual rock blocks is called rock creep.
In Jutana Formation, Khewra Sandstone and Sakaser Limestone of the Mapped Area, mass
movement of this type is observed in Karangal area as well as along the Chail Ridge.
Debris SlideDebris slides are common in Sakesar Limestone, Jutana Formation and Khewra Sandstone.
Rock debris fall dov..n along slopes in rolling motion under the influence of gravity.
2.9. Main Khewra Nala
The drainage pattern in the mapped area is dendritic drainage pattern .this drainage
pattern was developed along the anticlinical axes of the Khewra anticlines .the drainage
was developed after the deFormation of the anticline.the Khewra gorge which denotes the
main stream in the area is basically the anticlinal axis of the Khewra anticline but after
faulting and deFormation the present day drainage pattern was developed. the main
stream in the area is MAIN Khewra NALA.
In this drainage pattern water flows from upper northern area to down ward in to the main
Khewra nala towards the south.
The bifurcation ratio (Rb) for main Khewra nala is determined such as:
2.9.1.Bifurcaton Ratio Of Main Khewra Nala:
STREAM ORDER VALUES
Stream of 1st
order (a) 50
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Stream of 2nd
order (b) 16
Stream of 3rd
order (c) 4
Stream of 4th
order (d) 1
FORMULA USED
Stream of 1st
order (a) +Stream of 2nd
order (b) +Stream of 3rd
order (c)
Rb= Stream of 2nd
order (b)+ Stream of 3rd
order (c)+ Stream of 4th
order (d)
Mean
OR
By putting the values
Rb = 50/16 + 16/4 + 4/1
64
3
Rb = 200+256+256
a + b + c
b c d
Rb= Mean
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64
3
Rb =11.25 = 3.7
3
Bifurcation ration of the main Khewra nala is 3.7.
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2.10..Choa Saidan Shah Pidh Nala
This drainage pattern is of sub-parallel type .different large and small scale tributaries were
connected near choa-saidan shah city and around pidh area .
Here the channels of the water were less as compare to gorge nala.
2.10.1.Bifurcaton Ratio Of Choa Saidan Shah-Pidh Nala:
STREAM ORDER VALUES
Stream of 1st
order (a) 20
Stream of 2nd
order (b) 6
Stream of 3rd
order (c) 2
Stream of 4th
order (d) 1
FORMULA USED
Stream of 1st
order (a) +Stream of 2nd
order (b) +Stream of 3rd
order (c)
Rb= Stream of 2nd
order (b)+ Stream of 3rd
order (c)+ Stream of 4th
order (d)
Mean
OR
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By putting the values
Rb = 20/6 + 6/2 + 2/1
6
3
Rb = 20+18+12
6
3
Rb =8.33 = 2.7
3
Bifurcation ration of the Choa saidan Shah Pidh Nala is 2.7.
a + b + c
b c d
Rb= Mean
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FIG 2.1
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Chapter- 3
STRATIGRAPHY
3.1 Introduction
In the assigned area ,the rocks are mainly of sedimentary origin, ranging from pre
Cambrian to Eocene
The rock units exposed in the mapped area are as follow:
Recent to Sub Recent alluvium Early Eocene Sakesar Limestone Early Eocene Namal Formation Unconformity Early Permian Warchha Sandstone Early Permian Dandot Formation Early Permian Tobra Formation Unconformity Late Cambrian Baghanwala Formation Middle Cambrian Jutana Formation Early Cambrian Kussak Formation Early Cambrian Khewra Sandstone precambrian Salt Range Formationin Nilawahan group sardhi Formation is absent.
There are three unconformities .there is unconformity between Khewra sand stone and
kussak Formation and a well known major unconformity present between Cambrian
and Permian period , and the third unconformity is present between warcha sand stone
and Namal Formation .
The stratigraphic table is shown below .
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STRATIGRAPHIC TABLE OF THE ASSIGNED AREA
Table 3.1: Stratigraphic succession of Eastern Salt Range (Khewra
Gorge)
No. Age. Formation. Lithology.
10. Early Eocene Sakesar Limestone Massive and Nodular Limestones, with Marls ,
Chert in upper part
9. Early Eocene Namal Formation Light Gray Calcareous Shales and Limestones
Unconformity
8. Early Permian Warcha Sandstone Red and Light Colored Sandstones and Grits ,in
part Arkosic, Clay Interbeds
7. Early Permian Dandot Formation Olive green and Gray Sandstones and Shales ,
occasionally Carbonaceous
6. Early Permian Tobra Formation Conglomeratic Sandstones and Shales, Boulders
mainly Igneous or Metamorphic
Unconformity
5. Late Cambrian Baghanwala Formation Blood Red Shales and Flaggy Sandstones
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3.2. Stratigraphy
3.2.1 Salt Range Formation
Nomenclature and Type Locality
The term Salt Range Formation has been introduced by Asrarullah (1962) after the
Salt Range in the Punjab Province. Previously it was named as "Saline Series by Wynne
(1878) and Punjab Saline Series by Gee (1945). Khewra Gorge (lat. 3240N; long.
730030 E) in the Eastern Salt Range, Jhelum district, Punjab Province, has been
designated as the type section (Shah,1977).
Lithology
In the Mapped Area the Formation is composed of gypseous marl in the lower part .The
marl is massive and includes gypsum, dolomite and clay. Quartz crystals of variable sizes
are also present in this marl. It is white to light grey in color. It is massive and is associated
with bluish grey clay. The dolomite is light in color. It is flaggy and cherty in nature. It is
associated with dolomitic shales, bituminous shales. The oil shales when freshly broken
give off oily smell. Oil shales are of dark brown color and weathering color is very dark.
There are elongated nodules containing bituminous material. They show cavities filled with
calcite.
Distribution and Thickness
Salt Range Formation is widely distributed in the southern parts of the area, but it is only
restricted in the nalas. Its thickness was not measured because base of the Formation is
not exposed.
Contacts
Base of the Formation is not exposed anywhere including the study area. The upper
contact with the Khewra Sandstone is transitional.
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Age
The Salt Range Formation is devoid of fossils. Due to its position below Lower Cambrian
sediments and above the metamorphic Precambrian basement, it is considered as Late
Neoproterozoic. This is in accordance with the results of sulphur-isotope measurementscarried out on gypsum samples from the top of Salt Range Formation which indicate an age
of about 600 m.y. (H.A. RAZA)
FIG 3.1 :
Field Photograph Showing Salt Range Formation in the Khewera Gorge at
(Long 73o
00/
11//
, Lat 32o
39/
41//
)
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3.2.2 Khewra Sandstone
Nomenclature and Type Locality
The Khewra Group of Noetling (1894) is formalized as Khewra Sandstone after theKhewra town in the Punjab Province. Other terms were "Purple Sandstone Series of
Wynne (1878), "Khewra Group of Noetling (1894) and Purple Sandstone of most
subsequent authors. Khewra Gorge (lat.3240N; long. 7300E) in the Eastern Salt
Range, Jhelum district, PunjabProvince, is designated as the type locality.
Lithology
Khewra Sandstone dominantly consists of sandstone with minor amount of shale. The
basal part consists of thin-bedded, fine to medium-grained sandstone, partly shaly, passing
upward into massive, thick-bedded, purple, occasionally buff-colored, jointed sandstone
with thin bands of clay. Upper part is dominantly reddish brown and yellowish brown
sandstone, becoming pale towards the top. The sandstone is well sorted, cross bedded
and has abundant ripple marks and mud cracks and also shows convolute bedding in the
lower part .
The Khewra Sandstone can be divided into 4 units: (Saqib et. al 2009)
1. The lower unit, often called the Maroon Shale Group, consists of thin bedded, dark red
to brown, argillaceous siltstone, with intercalations of dark purple shales. Occasionally
argillaceous sandstones are present.
2. The middle unit is a thin bedded to flaggy, purple to brick red sandstone. It is generally
micaceous, fine grained and silty at the base; the grain size increases towards the top.
Sedimentary structures like ball and pillow, climbing ripples, parting lineation, tabular and
trough cross bedding are present.
3. The upper unit consists of light red to yellowish white sandstone which is medium hard
to friable. It gets coarser towards the top. Wedge planar cross bedding, large scale trough
cross bedding, honey comb weathering are prominent feature of this.
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4. The topmost unit of the Khewra sandstone is yellowish white, friable, medium grained,
sandstone which shows high percentage of quartz. The sandstone is ferruginous; cross
bedded and contains calcareous lenses.(FIG 3.2)
Distribution and Thickness
Khewra Sandstone is widely distributed in the southern parts of the area, but it is only
restricted in the nalas. More than 200 m in Khewra gorge.
Contacts
The contact of Khewra Sandstone with the underlying Salt Range Formation is conformable
and gradational. Its upper contact with Kussak Formation is sharp .
Age
The Khewra Sandstone does not contain well-preserved fossils but possesses evidence
of organic remains and trace fossils which have been interpreted as diggings of
trilobites (Schindewolf and Seilacher, 1955).Because of its position between the Late
Proterozoic Salt Range Formation and the fossiliferous Early Cambrian Kussak Formation,
in the Eastern Salt Range the Khewra Sandstone is thought to represent the basal part of
the Lower Cambrian.(Schmdewalf and seilachaclass)
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FIG 3.2
Field Photograph of Khewera Sandstone in the Khewera Gorge at the
(Long 73o
00/
02//
E and Lat 32o
39/
44//
N)
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3.2.3. Kussak Formation
Nomenclature and Type Locality
The "Kussak Group" ofNoetling (1894) is formalized as Kussak Formation after Kussak Fort
in Eastern Salt Range. Obolus or Siphonotreta Beds of Wynne (1878), Neobolus Beds of
Waagan (1884) and Kussak Stage of Pascoe (1959). Kussak Fort eastern Salt Range, District
Jhelum, Punjab.
Lithology
Kussak Formation contains shale with thin bands of glauconitic sandstone. Shale 1s
grey, greenish grey and purplish in color. Sandstone is micaceous.(FIG 3.3)
In the Mapped Area were found greenish grey shales and thinly bedded micaceous
sandstone. In the upper part sandstone becomes calcareous. Ripple marks worm tracks
were observed.
Thickness and Contacts
At type locality it is thick while in Mapped Area its thickness is 10 feet. It is outcropped
along west facing scarp in Khewra gorge.
It has sharp, conformable contact with Khewra Sandstone while upper contact with Jutana
Formation is transitional.
Fossils and Age
The Formation is fossiliferous, especially in the upper part. Schindewolf, Seilacher (1955)
and Pascoe reported following fossils. Neobolus Warthi, Lingulella wanniecka, HyolithesWynni and Redlichia noetlingi. Age of the Formation is Early Cambrian.(Schindewolf and
seilacher 1955)
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FIG 3.3
Field Photograph of Vertical Bioturbation in Kussak Formation along the Choa SaidanShah Road
(Long 72o
53/
21//
E and Lat 32o
41/
01//
N)
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3.2.4. Jutana Formation
Nomenclature and Type Locality
The Jutana Group of Noetling (1894) is formalized as Jutana Formation after Jutana Village
in eastern Salt Range.Magnesium Sandstone of Fleming (1852) "Jutana Group" ofNoetling
(1894)".Jutana village, District Jhelum Eastern Salt Range, Punjab Province.
Lithology
Jutana Formation is composed of dolomite, shale and sandstone. In the Mapped Area this
Formation can be divided into three units, lower sandy dolomite, middle shaly portion
(similar to Kussak) and upper pure dolomite characterized by chop board
weathering. (FIG 3.4)
Thickness and Contacts
The Formation is widely distributed in southern part ofthe Mapped Area. Typical cliffs of
Jutana Formation can be seen in Khewra gorge.
At type locality the thickness is 240 ft whereas it is 300 feet thick while in Mapped Area it is
about 60 m thick.
The contact with underlying Kussak Formation is transitional and with overlying
Baghanwa!a Formation is sharp.
Fossils and Age
The Formation contains tracks and burrows of Trilobite. Early Cambrian or Early Middle
Cambrian age is assigned to the Formation on the basis of faunal record.(Techert 1964)
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FIG 3.4
Field Photograph of Jutana Formation showing the thick beds of dolomites along Choa
Saidan Shah road at ( Long 72o
53/
25//
E and Lot 32o
41/
12//
N)
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3.2.5. Baghanwala Formation
Nomenclature and Type Locality
Baghanwala Group of Noetling (1894) is formalized as Baghanwala Formation after the
villageBaghanwala, Jhelum districPunjab Province.Wynne (1878) named as
Pseudomorphic Salt Crystal Zone. Holland (1926) called it Salt Pseudomorphic Beds.
Pascoe (1959) "Baghanwala Stage". Baghanwala village Eastern Salt Range, Jhelum District.
Lithology
It is composed of claystone,. Mud stone , Siltstone and thin bedded flaggy sandstone. The
flags are purple, grey or blue green. Primary sedimentary structures such as wave ripple
marks and mud cracks are present. Mud stone to silt stone (Upper lower part) are in blood
red color and characterized by pseudomorphic casts of salt crystals along the bedding
planes.(FIG 3.5 )
Presence of salt pseudomorphs, wave ripple marks mud cracks etc. indicate that Formation
was deposited under lagoonal envirorunent and arid climatic condition.
Thickness and Contacts
The Formation is mainly developed in Eastern Salt Range. Good exposures of Baghanwala
Formation can be seen in the Mapped Area.
At type locality the Formation is 300-350 feet thick. In the Mapped Area, the thickness is
20 feet due to erosion. The upper contact with Tobra Formation is unconformable
whereas lower contact is conformable with Jutana Formation.
Fossils and Age
No fossil record and Formation is Middle Cambrian in age.
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FIG 3.5
Field Photograph showing Thin interbedded of sandstone and shale of Baghanwala
Formation at (Long 72o
49/
13//
E and Lat 32o
30/
21//
N)
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3.2.6 Tobra Formation
Nomenclature and Type Locality
The term Tobra Formation has been introduced by Gee (written communication, 1964),for the lowest unit of the Nilawahan Group. "Talchir Series" of Blanford (1856),
"Talchir Conglomerate", "Talchir Stage" of Gee (in Pascoe, 1959), "Talchir Boulder Beds" of
Pascoe (1959), "Salt Range Boulder Bed" of Teichert (1967) were known in previous
literature. Tobra village (lat.3240N; long. 7250E) Eastern Salt Range, Jhelum district,
Punjab Province
Lithology
The Formation includes following units from base to top
Boulders which are mainly pink granites and grayish quartzite.
Red pebble bedded sandstone.
Grayish cross bedded siltstone
White massive sandstone.
Black shale with grit lenses
Distribution and Thickness
It is only present in the southern part of the Mapped Area, along nalas. The Formation has
a thickness of 10m. (FIG 3.6)
Contacts
The lower contact of the Tobra Formation is a widespread unconformity with baghanwala
Formation while The upper contact with the Dandot Formation is (gradational)
conformable. The contact can be recognized with change in lithology from black and
dark brown shale to greenish sandstone of Dandot Formation
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Age
The Tobra Formation contains ostracizes, and fresh water bivalves, pollen, spores,
microplanktons as well as flora remains including Glossopteris and Gangamopteris (Reed
1936). On the basis of fauna the age is considered as Early Permian (Shah, 1977).
FIG 3.6
Field Photograph Showing Contact b/w Tobra Formation and Dandot Formation along
the Choa Saidan Shah Road at (Long 720
45/
21//
E and Lat 32o
30/
21//
N )
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3.2.7.Dandot Formation
Nomenclature and Type Locality
The Dandot Group of Noetling (1901 a, b) is formalized as Dandot Formation after the
village Dandot in Eastern Salt Range, Jhelum district, Punjab Province. "Olive Series",
"Conularia Beds", "Erydesma Beds of Wynne (1878), "Speckled Sandstone" of Waagen
(1879), and "Dandot Group" of Noetling (1901) were different names assigned for this
Formation. East of Dandot (lat. 3239N; long. 7258E) Jhelum district, Punjab Province.
The Khewra-Choa Saiden Shah road section is designated as the principal reference section.
Lithology
In the Mapped Area the lithology consists of light-grey to olive green sandstone with
occasional pebbly beds and subordinate shale Distribution and Thickness.
The Formation is well exposed toward the Dandot village, in the Mapped Area it is not well
exposed. The thickness of this Formation in the mapped area is 12m.(Fig 3.7)
Contacts
The Dandot Formation has a gradational contact with the underlying Tobra Formation. The
upper contact with Warchha Sandstone is conformable and sharp
Fossils
The Formation contains rich fauna of brachiopods, bivalves, gastropods, pteropods,
bryozoans and ostracodes, as well as spores (Kadri, 1995).
Age
On the basis of the stratigraphic position of the Formation above the Tobra Formation, and
the presence of fauna in the Formation, Early Permian age has been assigned. (Telchert
1967)
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FIG 3.7:
Field Photograph Showing Contact b/w Dandot Formation and Warcha Sandstone the
Khewera Gorge at
(Long 72o
59/
49//
E and Lat 32o
33/
21//
N)
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3.2.8. Warchha Sandstone
Nomenclature and Type Locality
The name Warchha Sandstone was coined by Hussain (1967), prior to this other terms were
Warchha Group by Noetling (1901) after the Warchha Gorge in the Salt Range in Mianwali
district, Punjab Province. "Middle Speckled Sandstone" of Waagen (1889-91) and "Speckled
Sandstone" of Gee (1945) were also prevalent in literature. The type section of Warchha
Sandstone is Warchha Gorge (lat. 3227N; long. 7158E), in Central Salt Range, Punjab
Province.
Lithology
This Formation consists predominantly of sandstone. The sandstone is red,purple or lighter
shades of pink color. It is medium to coarse-grained and is pebbly, friable and arkosic. The
pebbles are of mostly of pink granite, quartzite and feldspar. The sandstone is thick bedded. It
is highly jointed and is locally speckled. (Fig 3.8)
Distribution and Thickness
The Formation is widely distributed in the southern and south western part of the mapped
area. It is mainly present along the nalas; Khewra gorge upper portion of the Khewra scarp.. It is
57m thick in the Mapped Area.
Contacts
The lower contact with Dandot Formation is conformable and sharp. The upper contact with
the Sardhai Formation is transitional which is placed at the top of the highest massive
sandstone.
Fossils
No diagnostic fossils are known from this Formation except from worm- casts and petrified
wood (Fatmi, 1973).
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Age
On the basis of stratigraphic position, Early Permian age has been assigned to this
Formation.(Hussain 1967)
FIG:3.8
Field Photograph Showing Warcha Sandstone in the Khewera Gorge
(Long 72o
49/
59//
E and Lat 32o
33/
21//
N)
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3.2.9. Namal Formation
Nomenclature and Type Locality
The "Namal Limestone and Shale" of Gee is formalized as Namal Formation after the Namal
Gorge, in the Western Salt Range, Mianwali district of Punjab Province. Prior to this other terms
were "Namal Limestone and Shale" of Gee (1935), and "Namal Marl" of Danilchik and Shah
(1967). Namal Gorge, Western Salt Range, Punjab province, is type locality of this Formation.
Lithology
In the mapped area, lithology of this Formation consists of limestone in the upper part and marl
below. Limestone and marl is almost is equal parts but marl becomes dominant in the basal
part. The limestone is whitish to medium grey, argillaceous hard, dense, medium to thick
bedded. It is nodular in part. Crystallization of calcite was noted in the joints.
Foraminifera are seen as small whitish specks on the weathered surface. Marl is whitish to
medium grey calcareous claystone which becomes silty at places. (FIG 3.9)
Distribution and Thickness
This Formation is widely distributed in the northern part of the Mapped Area. It forms
continuous escarpments. It is 20 -30 m thick in the Mapped Area.
Contacts
The lower contact of Namal Formation is placed at the top of gentle slope formed by underlying
warcha Formation. The contact is conformable with a thin transitional zone of grey marl
and shales. The upper contact with the Sakesar Limestone is conformable, sharp and distinct
Fossils
The Formation contains mollusks and foraminifera. Some important foraminifera include
Nummulites atacicus, N. subatacicus, N. mamillatus, N. irregularis, Assilina granulose, A.
laminosa, A. spinosa, A. subspinosa, A. daviesi, Lockartia tipperi, L. hunti, L. conditi and
Discocyclina ranikotensis (Kazmi and Abbasi, 2008).
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Age
On the basis of the above fauna, Late Paleocene to Eocene age has been assigned to this
Formation.
FIG 3.9
Field Photograph Showing Nodules of LimeStone in the Namal Formation at Choa saidan shah
Road (Long 72o 58/
22//
E and Lat32o 41/
34//
N)
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3.2.10 Sakesar Limestone
Nomenclature and Type Locality
The term "Sakesar Limestone" has been introduced by Gee after the peak Sakesar in the
Central Salt Range. Sakesar Peak (lat. 3231'30"N; long. 7136'E), Central Salt Range.
Principal reference section is Bhadrar village (lat. 3241'N; long. 7231'E) in Eastern Salt Range,
Jhelum district, Punjab Province.
Lithology
The Formation consists predominantly of limestone with subordinate marl. The limestone
throughout its extent is cream colored to light grey, nodular, usually massive with
considerable development of chert in the upper part.
In the mapped area, the Sakesar limestone is composed of dense homogeneous limestone
which varies from light grey to dark grey in color. It is massive too thick bedded and is highly
fossiliferous at places. (FIG 3.10)
Distribution and Thickness
It is widely distributed in the northern part of the mapped area. It is not measured in the
Mapped Area.
Contacts
The Formation conformably overlies the Namal Formation.
Fossils
The Sakesar Limestone has a sporadic capricious distribution of fossils. Foraminifers are most
abundant followed in numbers by mollusks and echinoids.
Age
On the base of fauna, Early Eocene age has been given to this unit(Kazmi and Abbasi, 2008)
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FIG 3.10
Field Photograph of Sakesar Limestone showing Chert Nodules near Choa saidan shah City(Long 72
o59
/21
//E and Lat32
o43
/4
//N)
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Chapter- 4
SEDIMENTARY STRUCTURES
Following sedimentary structures were observed from the Mapped Area.
4.1.Cross Bedding
4.2. Ripple Marks
4.3. Worm Tracks
4.4. Nodule Structure
4.5. Salt Pseudomorphs
4.6. Karen Structure
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4.1. Cross Bedding:-
we observed Cross bedding in the mapped area these structures are present in Khewera
Snadstone in the Khewera Gorge.
FIG 4.1 : Field Photograph Showing Cross Bedding in Khewera Sandstone.
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4.2. Ripple Marks:-
In the mapped area Oscilatory ripple marks were present at the base of KUssak Formation,
Baghanwala Formation and Warcha Sandstone .The ripples preset in the Kussak Formation is
Cross Ripple.
FIG 4.2 : Field Photograph Showing Ripple Marks in Kussak Formation.
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4.3. Worm Tracks:-
We have observed worm Tracks and burrows in the Kussak Formation which were of the
vertical and horizontal type .the shally Portion of Jutana Formation was also Contain the
Burrows .
FIG 4.3 : Field Photograph Showing Worm tracks and Burrows in Kussak Formation.
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4.4. Nodule Structures:
We observed large Nodules in the Namal Formation .These werw Chert Nodules .The nodules of
Namal Formation are longer than the Nodules of Sakesar Limestone.
FIG 4.3 : Field Photograph Showing Chert Nodules in Sakesar Limestone and Namal Formation
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4.5. Salt Pseudomorphs:-
Salt Pseudomorphs were present in the Baghanwala Formation pf the mapped area .Great
exposure of Pseudomorphs was seen in the Baghanwala Formation near Pidh and Khewera
Gorge.
FIG 4.5 : Field Photograph Showing Salt Pseudomorphs in Baghanwala Formation near Pidh .
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4.6. Karen Structures:-
Well Preserved Kurn Sedimentary Structure were found In the salt Range Formation in the
Khewera Gorge.
FIG 4.6 : Field Photograph Showing Kurn Structure in Salt Range Formatuion.
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Chapter- 5
DEPOSI'I'IONAL ENVIRONMENTS
5.1. Salt Range Formation
The Saline deposits are formed by the precipitation of salts from concentrated solutions
or brines. Because the concentration is brought about by evaporation, the saline deposits have
been termed as evaporites. Rock salt (halite) gypsum and anhydrite are deposited in this way.
The Salt Range Formation consists of salt marl, clay, gypsum, anhydrite, dolomite and rock salt
(halite). The ultimate source of the Salt Range Formation is normal sea water. The deposition of
Salt Range Formation took place in an enclosed, shallow water and partially isolated basin
during Late Pre Cambrian . An arid climate prevailed resulting in the deposition of
evaporite deposits under oxidizing conditions. The elastics were derived from Indian Shield
(Peninsular India).
The Salt Range Formation was deposited in arid region, enclosed basin received large
quantities of dust from atmosphere and by streams during rainy seasons. The
terrigenous material settled to the bottom and gave rise to layers of clay which later on
changes into marl by the reaction of acid vapors and solutions (Oldham). Red color of marl
indicates arid oxidizing conditions at the time of deposition. Lack of stratification in the
Formation is due to the diaprism of salt. High salinity was responsible for the absence of life.
Provenance
Fineness of material and good sorting indicate prolonged transportation from the'Peninsular
India. Continuous subsidence of the basin and incoming of water resulted in huge accumulation
of evaporitic deposit.
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5.2. Khewra Sandstone
The Formation predominantly consists of purple color, shaly, thinly bedded at base and thickly
to massively bedded at upper part. Presence of oscillatory ripple marks suggests shallow water
marine conditions.
After the deposition of Salt Range Formation, free supply of water began in the basin.
Numerous streams charged with the sediments from the Indian Shield drained into the basin.
The arid climatic conditions were prevailed at the time of deposition. The lower reddish,
purplish portion indicate high temperature and oxidizing conditions. The light colored upper
portion suggests less intensity of oxidation and relatively low temperature.
Lack of fossils and organic remains indicate high salinity and silica content suggests acidicmedium. (Pattijohn)
Origin and Provenance
Quartz grains are fine to medium, sub angular to sub rounded. Well sorting of quartz grains
show that the sandstone is texturally and mineralogically mature. Well sorting and maturity of
sandstone indicate a long transportation before deposition. It also suggests dilute depositing
medium with very mild subsidence of the basin during deposition.The source rocks were
possibly of granitic composition in the Southern India.
5.3. Kussak Formation
At the contact of Kussak Formation and K.hewra Sandstone a gritty conglomerate band is
present which shows a change in environment.
The Formation contains greenish grey glauconitic sandstone and greenish grey shale deposited
altematingly. The sandstone is micaceous. Alternation of shale and sandstone suggests cyclic
deposition i.e. during rainy season flooded streams were able to carry greater loads of coarser
sediments while during dry seasons load carrying capacity of streams reduced and only fine
materials were supplied and deposited.
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Green color of the Formation is due to the presence of mineral glauconite. Glauconite is a
potassium iron silicate which is formed under conditions of slow sedimentation in a partially
restricted environment. Glauconite was derived from biotite by sub marine weathering
(GaJlihar1935). Glauconite is formed in marine environment at a moderate depth from 200
fathoms to 300 fathoms. According to Cloud (1955) glauconite is formed under marine waters
of normal salinity. It requires slightly reducing conditionsThe presence of oscillatory ripple
marks at the base also indicates shallow water marine conditions..Salinity of the sea water was
normal because fossils are present.
5.4. Jutana Formation
Jutana Formation in the Mapped Area is composed of massive light cream to white hard sandy
dolomite at basal part, Kussak like fossils bearing shales in the middle and pure massive
dolomite in upper part.
Lithology of Jutana Formation and presence of sedimentary structures like ripple marks indicate
a shallow water marine environment and arid climatic conditions. The basin was partiall y
isolated and became rich in Mg by continuous evaporation and inflow of water. By the
precipitation of CaC03, Mg rich sea water attacks the CaC03 and replaces it by forming
MgC03.
The dolomitization of CaC03 resulted in a decrease of volume by 12.30% hence the porosity of
rock increased. But the Jutana Formation is hard and compact so the replacement of CaC0 3 by
MgC03 took place before lithification.
Sandy basal part and shaly intercalations indicate a continuous supply of detritus during early
stages of deposition. During the deposition of pure dolomite, the supply of detritus was ceased
or reduced. The rate of deposition is thought to be very slow so continuous stirring of bottom
by wave action in shallow marine environment helped in replacement. Salinity was not too high
to flourish life as fossils are present.
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5.5. Baghanwala Formation
The Formation consists of shale with intercalations of thin bedded flaggy sandstone. The flags
are pink, blue green or grey in color while shale is green and red in color.
Shales of the Formation are characterized by pseudomorphic casts of salt crystals which
indicate sufficiently high salinity in the water of depositional basin to form cubic crystals of rock
salt. Latter on these crystals were dissolved by the water and removed. The empty spaces of
the crystals were filled with silt or clay and were preserved. Green color of shale changing to
red is due to the oxidation of Fe+2 into Fe+3 Intercalations shale and sandstone is an evidence
of cyclic deposition which indicate that alternating wet and dry seasons were prevailed.
In short Baghanwala Formation was deposited in restricted basin of shallow depth whereoxidizing and arid climatic conditions were present. Salt pseudomorphs with absence of life
show the high salinity in the basin.
Provenance
Quartz and feldspar are the main constituent of the sandstone well sorting and fineness shows
a long transportation before deposition. The source of the sediments was same as Khev..Ta
Sandstone i.e. igneous rock but the sediments suffered a longer transportation due to the
shifting of shore line in retreating sea.
5.6. Tobra Formation
We noted glacial striations on faceted boulders of pink granite in the mapped area.. Striated
boulders suggest a glacial origin of the Formation.
Tobra mark an unconformity in the area. In the Mapped Area tilltic facies is present. It consists
of boulders and fragments of pink granite, quartz, phyllite and magnetite. The matrix is clayey
and sandy. Tobra Formation is very heterogeneous both in component material and in
assortment or stratification. Boulders of the Formation were transported from distant sources
by glaciers. These boulders are striated and faceted.
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Provenance
The provenance was first local and then changed to distant. At the base of Tobra Formation,
boulders of Khewrite and Khewra Sandstone represent local contribution of material while the
boulders and fragments of igneous rocks indicate a source lied in south i.e. Rajputana. Nagar
Parker pink granite is an evidence of this.
5.7. Warcha Sandstone
Light red or purplish color sandstone intercalated with sandy shales of dark purple color
comprised the warchha sandstone in the Mapped Area This sandstone is heterogeneous coarse
grained and pebbly. Cross bedding and ripple marks are observed. Pebbles embedded in
sandstone are of pink granite and quartz.
Warchha Sandstone was deposited in shallow water, fluvial environment. After the deposition
of Tobra Formation subsidence of the basin took place. The subsidence of the Western and the
Central Salt Range was earlier and more rapid than Eastern Salt Range because Dandot
Formation is present there.
Purplish and red color of sandstone and shales indicate shallow water, oxidizing environment of
deposition. Darker color of shale than the sandstone is due to the even distribution of coloring
matter (iron oxide).
Poor sorting suggests rapid deposition by dilute depositing medium. Presence of pebbles in
sandstone show high velocity of water and high relief of provenance.
Origin and Provenance
Composition of Warchha Sandstone shows that the material was derived from igneous rocks.
Coarse unsorted and angular grains indicate a short transportation by rapidly flowing dilute
medium. Deposition took place in a wide depression of shallow water.
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5.8.Namal Formation
Marly limestone of Namal Formation exhibits nodularity. It is richly fossiliferous and contains
both pelagic and benthonic fossil shells. The transitional contact between Patala and Namal
Formations indicate that transgressional sea changed swampy conditions into purelyshallow water marine environment.
Deposition of nodular limestone suggests high temperature and alkaline medium of
normal salinity in which life can flourish well that is why, the Formation is richly fossiliferous.
Marl was deposited as elastics by the streams flowing from land into the basin. Nodularity
may be developed by the process of sedimentation or may be formed due to shearing stress.
Provenance
Limestone is pure and fine grained. It is formed by direct extraction of CaC03 from sea water by
organic as well as inorganic means whereas marl is deposited mechanically by the incoming
streams.
5.9. Sakaser Limestone
Sakaser Limestone was deposited in shallow water marine environment. Hard compact and fine
limestone indicate relatively deeper water conditions than Narnmal Formation. Fairly constant
lithology and high lime content show calm and stable conditions of deposition. Like Namal
Formation, the limestone of Sakaser Formation also formed by direct extraction of CaC03 from
sea water by organic as well as inorganic means. Pelagic and benthonic fossils support shallow
water marine environment. Grey color is due to slightly reducing conditions. Absence of marl
indicates that stream action was ceased. Chert was formed by the post depositional
replacement of host rock by silica.
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Chapter- 6
GEOLOGICAL STRUCTURES
6.1. Faults:
There are three local and small scale local faults
Reverse Fault Normal Fault Grungal Thrust Fault
6.1.1.Reverse Fault:
The fault is a reverse fault in which hanging wall moved upward. the fault is near to the Khewra
George.
6.1.2. Normal Fault
In the mapped area there is another normal fault near Khewra Gorge in which Hanging wall has
been moved down of relative to Foot Wall .
6.1.3. Grangul Thrust fault:
As we know that salt Range is thrusted over Punjab Plain on the large scale while there is also
local and small scale thrusted fault .This fault is near Choa Siden Shah City , and the Namal
Formation and sakesar Limestone has been thrusted and they formed a thrusted fault Which is
also known as Grangul Fault.
6.2. Unconformaties:
In the mapped area two major unconformities and one minor unconformity is present.
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6.2.1. Disconformity:
A disconformity is found in the Early Cambrian Khewra sandstone and kussak Formation micro
conglomerate was present in the disconformity..
6.2.2. Permian unconformity
A well known unconformity is present between late Cambrian bgahanwala Formation and
Permian tobra Formation .tobra Formation mainly contains conglomerate which is a well
evidence of the unconformity.
6.2.3. Unconformity
There is another unconformity is present between a warcha sand stone and Namal Formation
in the mapped area.
6.2.4. Pidh Graben
Near the pidh area we observed a Grabon in the Nmal and Sakesar Limestone .The Graben two
sde were dipping equally about 40o .
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Chapter- 7
7.1.Introduction
Geological explorations are basically concern with the hunting of new economic minerals and natural
resources present within the earth. Minerals and rocks have a role in the economic uplift of a country
and Pakistan is no exception in this regard. Their geological investigation, evaluation and reserve
estimation would be helpful for the user industry. In addition, the possibility of discovering petroleum in
commercial quantities from the Potwar Plateau cannot be ruled out.
The east central fraction of the Salt Range (Mapped Area) is important due to its diverse economic
potential. The area is prosperous in varieties of industrial raw materials, construction materials and
economic industrial minerals. The exposed stratigraphic sequence suggests important petroleum system
elements including potential source, seal and reservoir rocks for oil and gas generation and
accumulation.
7.2.Energy Resources
7.2.1.Petroleum Play
There are several individual petroleum systems in this area. Each element of petroleum play is described
separately. Table 7.1 shows the source, reservoir and seal rocks distribution in the stratigraphic column of
the Mapped Area along with the possible timing of hydrocarbon generation and Formation of traps.
Table Petroleum system and events chart for the east central Salt Range (Mapped Area).
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Table 7.1 :Source Rocks ,Reservoir Rocks and Seal Rocks distribution in the Stratigraphy
Column of the Assigned area along with possible timing of hydrocarbon maturation and
Formation of the traps.
The stratigraphy of Salt Range has its subcrop extension under the Potwar Plateau. Therefore, the study
of outcrop units in Salt Range is very important and helpful to define the subsurface petroleum plays in
Potwar which is one of the onshore oil-prone areas in the world.
7.3. Source Rocks
There are several potential source rocks exposed in the mapped area. Among these are the well known
late Proterozoic Salt Range Formation.
The oldest potential source rocks are in the Salt Range Formation with a Total Organic Carbon (TOC) of
upto 36% (Bender and Raza, 1995) and oil yields of more than 20% (Kadri, 1995). The oil shales are
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present in the upper part of the Formation and are associated with dolomite and gypsum. Silled and
reducing basin conditions were favourable for the preservation of organic matter at that time. The oil
shales of Salt Range are equivalent to the Precambrian oil source rocks of India, Oman and North Africa.
The oil shales were observed and sampled from Khewra Gorge Kadri (1995) described the presence of
coal in Cambrian rocks in these words:
Shales of Khewra, Kussak and Jutana Formations are of lacustrine to marine origin and contain woody,
coaly to variously amorphous kerogene which are capable of generating paraffinic to normal crude and
gas. The maturity level for these strata is very high for their present depth, indicating their original deep
burial and then removal of the overburden by up thrusting along the boundary faults of Salt Range.
There are indications that hydrocarbons were generated in Cambrian source rocks.
Baqri and Baloch (1991) also reported lenticular, deltaic coal beds in upper part of Khewra Sandstone at
Nilawahan Gorge.
The International Committee for Coal Petrology (1963) defines coal as, a combustible sedimentary rock
formed from plant remains in various stages of preservation---temperature and Pressure. Vascular land
plants only appeared during Middle Silurian (Stewart, 1983 and Taylor and Smoot, 1984). Therefore, the
presence of woody and coaly beds in Cambrian strata is not sound. Starting in the Precambrian till the
Devonian, the sole primary producer of organic matter was marine phytoplankton (algae and fungi) that
made black, organic matter rich, open marine shales (Tissot and Welte, 1984). Therefore, only algal-
matter derived organic matter may be present in the Cambrian rocks (Yasin, A.R., 1993).
Rocks of lower Permian sequence (Tobra, Dandot and Warchha Formations) are the possible source of
gas discovered in the Punjab Platform. Organic richness varies from 0.3 to 4.75%. The hydrogen index
ranges from 29 to 165 mgHC/gTOC. On the average it is fair to good. The organic petrography and
limited rock-eval data suggest that source is a mixture of Kerogene type II, type III and type IV (Ahmad et
al., 2007). Shales of Dandot Formation with some coaly partings are good source rocks (Kadri, 1995).
Paleocene presents and overall low energy and anoxic environment favoring the abundance and
preservation of organic matter. Upper Paleocene Patala Formation is considered to be the major source
rock of this region .TOC ranges from 0.5% to more than 3.5%, with an average of 1.4 percent, and are
type-II and -III kerogens (Wandrey et al., 2004). It has EOM/TOC ratio partly more than 150 and HI mostly
more than 200. The Formation was deposited in shallow marine to deltaic environment accounting for
the interpretation of both terrestrial and marine organic material. The latter gives rise to the generation
of normal crude oil while the former generates gas and paraffinic crude.
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Maturation
The source rock maturity is mainly related to the geothermal gradients and the thickness of overburden.
The geothermal gradient of Potwar region ranges between 1.5C and 2.6C/100 m. Post Eocene
sediments have played a very important role in maturity of younger source rocks in depression areas.
This period accounts for rapid clastic sedimentation at the expense of Himalayan uplift and subsequent
erosion of uplifted rocks.
The organic matter preserved in the Salt Range Formation did not get the maturity until the Permian.
Because, the thickness of Cambrian rocks was not sufficient for the deep burial and maturation of
organic matter.
Maturity level of Permian rocks also appears to be very high since they have undergone tremendous
change on account of their burial through both time and temperature (Kadri, 1995).
The most important source rock reached the oil window during Pliocene (Bender and Raza, 1995). A
basin profile indicates vitrinite reflectance equivalent maturities of 0.62 to 1.0 percent for Tertiary rocks
in the productive part of the Potwar Basin (Wandrey et al., 2004).
Generation and Migration
Petroleum generation is directly related to the scale of time and the thermal regime, the strata is
subjected to.Rapid burial of Eocene and older rocks have placed them in petroleum generation window
in the basinal areas.
Generation of hydrocarbons most likely began in Late Cretaceous time for Infracambrian and Permian
source rocks and again from Pliocene time to the present for younger source rocks.
Even though there were probably two distinct periods of generation from two different groups of source
rocks, sufficient source-to-reservoir correlation data were not available to clearly define separate
petroleum systems. Migration is primarily over short distances updip and vertically into adjacent
reservoirs and through faults and fractures associated with plate collision and thrusting (Wandrey et al.,
2004).
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7.4.Reservoir Rocks
Reservoir rocks include Khewra Sandstone, Jutana Formation, Baghanwala Formation, Tobra Formation
and Sakesar Limestone. More than 60 percent of the producing reservoirs (by field) are of Cenozoic age
in Potwar Plateau, with the majority of those being Eocene carbonates.
Fractured dolomite in the Salt Range Formation can form a suitable reservoir in the right setting with a
cap or seal to prevent migration. Possibility of entrapment of hydrocarbons in the overlying Formations
also exists, provided the hydrocarbons have not been destroyed during the hiatus of Ordovician to
Carboniferous times (Kadri, 1995).
Khewra Sandstone is the main potential Cambrian reservoir. The uniform grain size of sandstone and
sorting indicates its excellent reservoir character. The upper and middle units of the Formation are
moderately porous and display intergranular primary porosity which ranges from 10-15%. The
sandstone also shows fractures and jointing which may contribute to increase the effective
permeability. Oil is produced in Potwar area from Khewra Sandstone at Adhi, Chak Naurang and Rajian
Oil Fields.
Kussak Formation is generally tight. However, hydrocarbon shows are reported on both ditch sample
(fluorescence) and logs (Kadri, 1995).
The Jutana Formation is a good potential reservoir and hydrocarbon indications are reported in some
wells in the Potwar. It shows good porosity at outcrops, for example, honey-comb and fenestral
porosity). Upper part of the Formation has been proved as a good reservoir in the southeastern Potwar
area and oil is produced from Jutana Formation at Rajian Oil Fields.
Baghanwala Formation also has reservoir potential. Lower part of the Formation is a very well sorted,
medium grained quartz arenite which can act as an excellent reservoir .The visual porosity found by dye
injected thin sections is upto 15% .
The reservoir potential of the Permian rocks is also good. In the wells of the Potwar basin the Permian
sequence is very compact with very low porosity and permeability. At places Tobra Formation
depicts very good reservoir characteristics with presence of primary and
development of dissolution porosity (matrix porosities between 10% and 13%).
Moreover, sandstones of the Formation are fractured in vertical and horizontal
directions. However, Tobra Formation has flowed oil in Adhi Field (Kadri, 1995).
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The Dandot Formation displays more shales than siltstones and sandstones. The siltstones and
sandstones are well sorted and possibly develop into local reservoirs. The Warchha Sandstone is
medium hard to friable, highly porous,