GEOLOGY AND TECTONICS OF MIANWALI GORGESSUBMITTED TO: Dr.MONA LISA

Dated:10/12/2:

SUBMITTED BY: HUDA JADOON

DEPARTMENT OF EARTH SCIENCES

QUAID-E-AZAM UNIVERSITY ,ISLAMABAD.

CONTENTS

1. Acknowledgments2. Abstract3. Introduction

a) Division of Salt Rangeb) Tectonic Settings c) Stratigraphy of the Region d) Stratigraphic Table e) Boundriesf) Unconformities

4. Objective of Field 5. Methodology6. CHICHALI GORGE

Stratigraphy

FORMATIONS:

Murree Formation Sakessar Formation Nammal Formation Patala Formation Lochkart Formation Hangu Formation Chichali Formation Samana Suk Formation Shinawari Formation Data Formation

7. NAMMAL GORGE Stratigraphy

FORMATIONS:

Amb Formation Wargal Formation Chhidru Formation Mianwali Formation Tredian Formation Kingriali Formation

7.CONCLUSION

8.REFRENCES

ACKNOWLEDGEMENT

I would like to thank Almighty Allah for giving us the sense and strength to be a part of this field trip which was organized by the Earth Sciences Department of Quaid-e-Azam University.

This field trip is impossible to complete without the help and expertise of many people.The team at the field encouraged and advised me every step of the way.Their expertise and cheerfulness kept me motivated and ensured that I completed the task at hand and made it pleasurable experience.MY teacher Dr.Aamir Ali,Dr.Touqeer and Dr.Anwar navigated me through many of the groups,formations and members of the salt range.I also acknowledge the department of Earth Sciences and Quaid-e-azam University that helped alot in arranging the field for us in such crucial circumstances of our homeland.

ABSTRACT:

The Salt Range contains the most important geologic and paleontologic localities in Pakistan,and is one of the outstanding field areas in the entire world.Despite its easy accessibility,it has wealth of geological and paleontological features.In fact,it represents an open book of geology where various richly fossiliferous stratified rocks are very well exposed due to lack of vegetation.These include the Permian carbonate succession with its outstanding brachiopod fauna,Lower Triassic ammonoid beds(the Mianwali Formation,formerly known as “Ceratite Beds”).and Lower Tertiary marine strata with age diagnostic foraminifera.These rocks also provide an excellent opportunity for appreciation of tectonics in the field.

In addition to easily available roadside geology,some prominent gorges provide fantastic locations to study the sedimentary successions.Among those gorges,the gorges which we have studied in these three days field are Nammal Gorge and Chichali Gorge.

INTRODUCTIONThe Indus Basin of Pakistan is divided into two parts i.e.Lower Indus Basin and Upper Indus Basin.The Upper Indus Basin is further divided by Sargodha high way into two parts.Towards the east of the Sargodha highway is Potwar Plateau and towards the west is Kohat Plateau.The region of the North Punjab called as Potwar Plateau,is bound in the south by Salt Range and in North by MBT as shown in Figure 1.

Fig 1:Location of Salt Range

The name of Salt Range was first use by ELPHISTON in 1808.The name is derived from the fact that area contain huge reserve of the common table salt.

Salt Range is one the few important localities in the subcontinent for its interesting structural ,valuable stratigraphic and paleontological record.Salt Range is characterized by extensive Anticlines folds,Synclines folds and various ypes of faults.It is also important as a source of minerals e.g.Halite,gypsum,Coal,fire clay etc. Thae occurrence of these minerals is important in stratigraphic as well as paleontological point of view.That’s why Salt Range sequence of Pakistan has fascinated geologists from all over the world due to its preserved faunal assemblages.

a) DIVISION OF SALT RANGE:

The Salt Range is mainly divided into two parts.The area to the east of the river Indus ‘Main Salt Range’ and area to the west of the river Indus is called ‘Trans-Indus Salt Range’.The Main Salt Range is further divided into three parts:

Western Salt Range Central Salt Range Eastern Salt Range

Eastern Salt range is about 16km and its height about the sea level is 760m.The western Salt Range is widens westward to the width of about 32km with heighest altitude of about 1422km at Sakessar.Similar Central Salt Range is more wider then eastern and western salt range .

The Salt Range strikes almost East-West and terminates at Kalabagh.

b) TECTONIC SETTINGS: Approximately 20 million years ago india was connected to the south eastern tip of the Africa.Development of a rift in the crust is due to forces within the mantle.thus separating the indo-aushailian tectonic plate from the continent of Africa.Several million years later ,its leading deep sea floor edge began colliding with the Eurasian tectonic plate and thrusting downward.Evantually continuous continental-continental collision raised the leading oceanic edge above the sea level leading to continuous orogenesis the process that has created the great Himalayan mountain ranges.

c) STRATIGRAPHY OF THE REGION: The rocks of the salt range stratigraphic units ranges in the age from Pre-cambrian to the Tertiary with the marked absence of Ordovician,Silurian,Devonian and Carboniferous age throughout the region.Locally a given stratigraphic rock sequence pinches out laterally to the point of vanishing e.g.Mesozoic sequence is well developed in the western and Trans-Indus ranges but the Triassic and Jurassic and perhaps all the cretaceous formations are conspicuously absent in the most of the central and eastern salt range.

d) BOUNDRIES: Geological Boundries of Potwar PlateauEast…Jhelum faultWest…Kalabagh faultNorth…Potwar faultSouth…Sarghoda fault Geological Boundries of Salt Range East…Jhelum faultWest…Indus River

North…Soan RiverSouth…Punjab plains

e) UNCONFORMITIES: Several types of unconfirmities are also present in the area which also include paraconformity,Permotriassic unconformity and Permocambrian unconformity.These unconformities are further describe in the stratigraphic table given below in figure 2 and figure 3.

Fig 2: Diagrammatic illustration of the major unconformities in the Eocambrian to Tertiary sequence of the Salt Range_Surghur Range_Khisor Range(after Gee,1989).

Fig 3:Major Unconformities of Salt Range

Objective of Field :

Purpose of field is to enhance our knowledge and to get the more precise and practical work information of what we have studied in classroom and specially to concentrate on the structure of the area.Similarlt to study the sediments deposited in that particular area.In this we deal with primary and secondary features exposed in the area namely

Cross Bedding Folds Faultsparasitic folding Ripple marks Mud Cracks Nodules Understanding of environmental conditions from fossils or

some other features Stylolites

METHODOLOGY:

We applied different methods in our field to recognize the lithology,dipping direction,strike and our position etc.The following instruments are used to measure these geoloicalterms such as:

Brunton Compass Magnifying Lens Geological Hammer Dilute Acid

Brunton Compass:

We have used Brunten Compass in order to locate ourself.We used it

to determine dip and strike of different rock stratas.This instrument is shown as:

Magnifying Lens:

We have used Magnifying lens to differentiate between different constituents of a rock sample.It is shown as below

Geological Hammer: We have use hammer to get a fresh sample of rock units.

FIRST DAY OF FIELD REPORT

CHICHALI GORGE: Stratigraphy:The chichali gorge is situated about 25 km NW of kalabagh fault in Surghar range.The gorge is located near the village of tolamargi kher.The gorge is extended from chinji and shinawari formation to data formation.On the mouth of gorge the siwaliks are exposed.These were unconfirmable under the Eocene limestone that combine nodular limestone and chert limestone,and then ther is Patala formation of Paleocene age.Overlying Patala formation is Lockhart formation and after that is Hangu formation then come Lumshiwal and chichali formation.After that Samana Suk ,Shinawari not so exposed and Datta.And after that there are normal successions of the anticline.

Formations In Chichali Gorge

Nammal Formation:

This formation is the first member of the cherat group.Cherat group represents the Eocene strata of Salt Range.

HISTORY:

“Nammal Limestone and shale”by Gee (1935), “Nammal Shale” by Danilchik and Shah (1967),is named as Nammal formation by Stratigraphic committee of Pakistan.

LITHOLOGY:

Main lithology of this formation is shale,marl and limestone.Shale is grey to green and fossilefarous.Limestone is gray to bluish,argillaceous and highly fossiliferrous.Marl is light grey to bluish gray.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is shallow marine to lagoonal environment.

THICKNESS:

Thickness of this formation is its type locality is 100m.

CONTACT:

The upper contact of this formation is overlying Sakessar formation and is transitional and conformable.The lower contacyt of this formation is with underlyinf patala formation and this contact is also conformable.

FOSSILS AND AGE:

Various fossils found in this formation are Foraminifera and Mollusks.Dueto the presence of these fossils,age assignsed to this formation is Early Eocene.

SAKESSAR FORMATION:

This formation is the second member of Cherat Group.

HISTORY:

“Sakessar limestone” by Gee in 1935 was accepted by the Stratigraphic Committee of Pakistan.

LITHOLOGY:

Bulk of lithologu of this formation is limestone which is cream to light gray in color,nodular and massive in the upper part and also highly fossiliferrous.Light gray color Marl is also found in the top most part and having chert nodules.

THICKNESS:

Thickness of this formation in Salt Range is from 70-150m.

CONTACT:

The upper contact is with chorgali formation and this contact is transitional and conformable.The lower contact is with Nammal formation and it is also conformable.

FOSSILS AND AGE:

Various fossils found in this formation are foraminifera,Mollusks and Echinoids.Due to the presence of these fossils,the age assigned to this formation is Early Eocene.

HANGU FORMATION:

This formation is the first member of the Makarwal Group.Makarwal group represents the Paleocene strata of the Salt Range.

HISTORY:

The “Hangu Shale” and “Hangu Sandstone” by Davies (1930) have been formalized by the stratigraphic committee of Pakistan.

LITHOLOGY:

This formation consists if dark grey,rarely variegated sandstone,shale,carbonaceous shale,and some nodular argillaceous limestone.The sandstone is white,light grey adreddish brown,weathers dark rusty brown,fine to coarse grained and medium to thick bedded.

THICKNESS:

In the Salt Range area ,this formation is 40 to 45 m thick.

CONTACT:

The upper contact of this formation is with Lockhart formation and this contact is transitional and conformable.The upper contact of this formation is with Samana Suk formation and this contact is unconformable.

FOSSILS ANF AGE:

The various fossils found in this formation are foraminifera with some corals,gastropods and bivalves.Due to the presence of these fossils,the age assigned to this formation is Paleocene.

LOCKHART FORMATION:

This formation is the scong member of the Makarwal Group.

HISTORY:

Davis (1930) introduce the term Lockhart Limestone for a Paleocene limestone unit in the Kohat area.

LITHOLOGY:

Grey to dark grey ,medium to thick massive bedded ,brecciated limestone.The limestone display very well developed nodularity.The nodularity may be caused by any of the following four reasons:

Organic activity Differential compaction Pressure solution Stretching

ENVIRONMENT OF DEPOSITION:

The environment of deposition is shallow marine shelf conditions where calcite is precipated in warm water to form limestone.

THICKNESS:

In the Samana Range the formation is 60m thick.

CONTACT:

The upper contact with Patala Formation is transitional and conformable.The lower contact with Hangu Formation is also conformable.

FOSSILS AND AGE:

The limestone contain abundant Foraminifers,Corals,Mollusks,Echinoids and algae.On the basis of these fossils,the age of this formation is assigned as Middle Paleocene.

PATALA FORMATION:

This formation is the third member of the Makarwal Group.

HISTORY:

Davies Pinfold (1937) named it as Patala shale which later was renamed as Patala Formation by the SCP.

LITHOLOGY:

Alternate beds of Shale ,Clay and limestone.Thin bedded sandstone and some interbedded marl and conglomerate are also present.

ENVIRONMENTOF DEPOSITION:

The environment of deposition is translational,continental and deltaic marine environment.

THICKNESS:

Type locality is in Patala in the Salt Range area,where the thickness of the formation is 90meters.

CONTACT:

The upper contact with overlying Nammal Formation is translational and conformable.The lower contact is with Lockhart formation and it is also translational and conformable.

FOSSILS AND AGE:

The formation is richly fossiliferrous and contain abundant foraminifera and mollusks.One the basis of the above mentioned fauna,the age assigned to this formation is Late Paleocene.

CHICHALI FORMATION:

LITHOLOGY:

At the type locality at Chichali Pass,this uni consists of dark green to blue-black glauconitic shales and sandstones in marked contrast to underlying Jurassic. It has a greenish to rusty brown glauconitis sandstone in the middle that stands out from toography.At the top there is a layer rich enough in iron to constitute a low gade iron ore.

THICKNESS:

At Chichali Pass,The unit is about 75m thick.

CONTACT:

The Chichali Pass grades upward into the Lumshiwall Formation,and this contact is translational and conformable.

FOSSILS AND AGE:

Large number of Bullet like fossils called Billumnites(index fossil) are found in this formation.Presence of fool gold is also observed.On the basis of these fossils the age assigned to this formatin is Late Jurassic to Cretaceous.

MURREE FORMATION:

A section exposed to Dhok Maiki in the Attock District.

HISTORY:

The “Mar Group” of Wyne (1874) and “Murree Series” of Pilgrim (1910) have been formally named as “Murree Formation” by Stratigraphic Committee of Pakistan.The name is derived from Murree hill in Rawalindi District.

LITHOLOGY:

This formation is composed of monotonous sequence os dark red and purple clay and purple grey and greenish grey sandstone with subordinate intraformational conglomerates.The basal Strata of formation consist of light greenish grey sandstone and conglomerates with abundant deried larger foraminifera of Eocene age.

THICKNESS:

The formation is widely developedin the Kohat-Potwar province,also been recognized in Kashmir.It is upto 3030m thick in Northern Potwar but thins only to 9m at Banda Daud Shah in western Kohat.The formation ranges in thickness from 180m to 600m in northern salt range.

FOSSILS AND AGE:

The main body of formation is poorly fossiliferous and only few plants remains,silicified wood,fish remains,frog and mammalians bones have been recorded.However,the fatehjang member has yielded identifiable mammals indicating Brachyodus giganteu,Teleoceras fatehjangesisetc.The fauna indicates an early Miocene age for Murree Formation.

DATTA FORMATION:

This formation is the first member of the Surgher Group.Surgher Group represents the Jurassic and Cretaceous strata of the salt range.

HISTORY:

“Variegated stages” by Gee (1945),”Lower Part of Samana beds”by Davies (1930) is named as “Datta Formation” by Danichik in 1961.

LITHOLOGY:

Variegated beds of sandstones,siltstone and shale of different clors are present in this formation.Sandstone is red to maroon,grey,green and white in color.Sulphur is mostly present in this formation indicating swamo or deltaic environment.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is very shallow marine to deltaic and alluvial plains.

CONTACT:

Upper contact of this formation with shinawari formation is gradational and conformable.Lower contact with Kingriali formation is disconformable.

FOSSILS AND AGE:

This formation is poorly fossiliferous but some petrified wood is present there.Age assigned to this formation is Jurrasic.

SHINAWARI FORMATION:

This formation is the second member of the Surgher group.

HISTORY:

Lowest Samana beds by Davies (1930),”Lower Part of Kyoto Limestone” by Cutler (1933), is named as Shinawari formation.

LITHOLOGY:

Main lithology of this formation is medium to coarse bedded limestone which is grey to brownish grey in color.It is well bedded,sandyoolitic withnodular marl, shale and sandstone.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is very shallow marine,deltaic,tidal flat.

THICKNESS:

Thickness of the formation at type locality is 400m.

CONTACT:

Upper contact of this formation with Samana suk formation is translational and conformable.Lower contact with Datta formation is also conformable.

FOSSILS AND AGE:

Various fossils founf in this formaton are Ammonoites,Brachiopods and Corals.Due to presence of these fossils agr assignes to yhis formation is Middle Jurassic.

SAMANA SUK FORMATION:

This formation is the third member of the surgher group.Few beds of this formation are present in Nammal gorge but it is undifferential from Shinawri formation.

HISTORY:

‘Bared Limestone” by Gee, “Upper Part of Kyota limestone” by Cutler (1933), is named as Samana Suk formation by Davies in 1930.

Lithology:

Main lithology of this formation ismedium to thick bedded limestone of grey to dark grey in color.The limestone is ooliti with shale beds.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is shallow marine shelful to supertidalenvironment.

THICKNESS:

Thickness of this formation at type locality is 186m.

CONTACT:

Lower contact with shinwari formation is conformable and upper contact with chichali formation is unconformable.

FOSSILS AND AGE:

Various fossils found inthis formation are Brachiopods,Bivalves,Gastropods and Crinoids.

The rest of the three members of Surgher Group are absent alog major unconformity maned as K.T Boundary.

SECOND DAY OF FIELD TRIPNAMMAL GORGE:

AMB FORMATION:

It is the first member of Zalch group,represents he upper Permian strata of salt range.

HISTORY:

‘Amb sandstone beds’ by Waagen(1891), ‘Amb formation’ by Teichert is now called as Amb Formation by SCP.

LITHOLOGY:

This formation consist of thin to medium bedded sandstone and limestone.Thin beds of shale are also present.Limestone is light grey on fresh surface and grey to brown on weathered surface.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is shallow marine to palludal.

THICKNESS:

Thickness of this formation is 80m in type locality and 47m in Khisor range.

CONTACT:

Upper contact with Wargal formatin and lower contact with Sardhai formation are conformable but nor present in Nammal gorge.

FOSSILS AND AGE:

This formation is highly fossiliferrous.Typical microfossils are forms.Brachiopods are also present.Due to these fossils age assigned to this formation is upper Permian.

WARGAL FORMATION:

It is the second member of the Zaluch group.

HISTORY:

“Wargal group” by Noetling (1901),” Middle Productus limestone” by Waagen(1879),is now called as Wargal formation by SCP.

LITHOLOGY:

This formation consists of limestone and dolomite.Limestone is somewhat nodular while dolomite is pinkish grey in color and massive.Black color chert are also present here and small scale faults is also visble.

THICKNESS:

The thickness of this formation is 182m.

CONTACT:

Upper contact with chiddru formatin is translational and conformable and lower contact with Amb formation is conformable and sharp.

FOSSILS AND AGE:

Various fossils found are Brachiopods,Gastropods and trilobites and age assigned to his formation is Middle Permian.

CHHIDRU FORMATION:

This formation is third member of Zaluch Group.

HISTORY:

“Chhidru beds” by Waagen (1891(, and “Chidru Group” by Dunbar (1932), is now called as Chhidru formation.

LITHOLOGY:

Main lithology of this formation include limestone,sandstone and limy sandstone.Shale units of grey to dark grey color are also present.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is shallow marine,littoral to palludal.

THICKNESS:

Its average thickness at type locality is 64m.

CONTACT:

The lower contact with wargal formation is conformable and upper contact with Mianwali formation is unconformable.

FOSSILS AND AGE:

Brachiopods and ammonoites are found.ge assigned is Late Permian.

MIANWALI FORMATION:

This is the first member of Musa khel group. Represents the Triassic strata of the salt range.

HISTORY:

“Lower Part of Mianwali Series” bu Gee (1959) “Top Part limestone and dolomite beds” by Waagen (1879). Was named as Mianwali Formation.

LITHOLOGY:

This formation is composed of limestone,siltstone,dolomite and sandtone.

ENVIRONMENT OF DEPOSITION:

Environment of deposition of this formation is open marine to detaic environment.

THICKNESS:

Thickness of this formation is 127m.

CONTACT :

The lower contact with chiddru formation is marked Paraconformity and upper contact with Tridian formation is sharp and conformable.

FOSSILS AND AGE:

The fossils found are brachiopods and conodonts.Age of this formation is Lower Triassic.

TREDIAN FORMATION:

It is the second member of the Musa khel Group.

HISTORY:

‘Kingriali sandstone” by Gee (1948), is Tridian formation ny Kummel and Gee in 1966.

1. LITHOLOGY: : Main lithology of this formation is sandstone, which is medium to thick bedded and upper part is massive. Few beds of shale, siltstone and sandy limestone are also found.

2. ENVIRONMENT OF DEPOSITION: Environment of deposition of this formation is shallow marine to deltaic.

3. THICKNESS: The thickness of this formation in Zaluch Nala is 76m.4. CONTACT: Lower contact with Mianwali formation is sharp, well- defined and conformable. The upper

contact with Kingriali formation is also gradational and conformable.5. 25.   25 FOSSIL AND AGE: The various fossils found in this formation are plant microfossils. Due to the

presence of these fossils the age assigned to this formation is Middle Triassic. Contact between Tredian and Kingrilai Formations

KINGRIALI FORMATION

 It is the third and last member of the Musakhel group. HISTORY: “Kingriali Dolomite” by Gee (1943) is named by Gee again in 1945 as “Kingriali formation” LITHOLOGY: The bulk of lithology is dolomite, dolomitic limestone with interbeds of dolomitic shale. The dolomite is thin to medium bedded, fine grained with inter beds of shale and marl. Cross beds are also present in this formation. ENVIRONMENT OF DEPOSITION: Environment of deposition of this formation is shallow marine environment. THICKNESS: The average thickness of this formation is 76-106m. CONTACT: Lower contact of this formation is with Tredian formation and is conformable. Upper contact is with Datta formation of Jurassic age and the contact is Disconformity. FOSSIL AND AGE: Poorly preserved Brachiopods, Bivalves, and crinoids are present in this formation. Age assigned to this formation is Early Triassic.