Stratigraphy.5

[ ] Stratigraphy

5.1 Introduction

The Salt Range is a hill system in the Punjab province of Pakistan, deriving

its name from its extensive deposits of rock salt. The Salt range of Pakistan forms part of

sub Himalayan Mountains which stretch more than 180 Km East-West between the

Jehlum and Indus Rivers, along the southern margin of the Potwar Plateau. A thick

sedimentary cover of Precambrian to recent deposits overlies low grade Metamorphic

and Igneous Rocks with an unconformable contact. (Gee 1989).The Salt Range contains

the great mines of Mayo, Khewra, Warcha and Kalabagh which yield vast supplies of

salt. Rocks of Salt range was uplifted by a thrust fault called Salt Range thrust, which

emplace older rocks of salt range upon younger rocks of less deformed tertiary rocks of

Jhelum plain.

The lithostratigraphic units range in age from Infra-Cambrian to Recent and

mainly consist of sedimentary sequences are found in Salt Range, which are punctuated

by unconformities both of local and regional extent (Qadri, 1995). Sakaser and Tilla

Jogian are the highest peaks of Salt Range. The area displays some excellent geological

exposures in valley and gorges representing geological history from 600m years to

recent with the absence of Ordovician, Silurian and Devonian over a distance of

few kilometers. And therefore is known as field museum of Geology.

5.2 Distribution of Various Unconformities in Salt Range:

The distribution of the various formations in Salt Range is governed by four

major unconformities. (Fig 5.1) and Satellite Image is Shown in Fig 5.2.

I. At the base of Permian:The conglomeratic Tobra Formation oversteps the Cambrian westward and

northward, coming to rest directly on Salt Range Formation of the western part

of Salt Range.

II. At the Base of Tertiary:At the base of tertiary in the extreme Eastern part of the Salt Range the Paleocene

directly overlies the Cambrian sequence, Jehlum Group. Westward and

northward it rest on the Permian and Mesozoic sequence.

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[ ] Stratigraphy

III. At the base of Lower Miocene Rawalpindi group:Generally this unconformity intensifies southward, as a result Upper Miocene

Formations Occasionally rest directly on diminutive Eocene or on Triassic in the

southern repetitions of the western part of the scarp.

IV. At the Base of Kalabagh Conglomerates:This unconformity lies in the Western part of the Salt Range, at the base of

Kalabagh Conglomerate.

Fig.5.1 Diagrammatic illustration of major unconformities in Eocambrian to

Tertiary sequence in Salt Range (After Gee 1983)

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[ ] Stratigraphy

Table No 01: General Stratigraphy of Salt Range

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[ ] Stratigraphy

List of Observed FormationsAge Formation Lithology Lithology

Description

PleistoceneKalabagh

Conglomerate Conglomerate

MioceneKamlial Formation

Sandstone

Eocene

Sakesar LimestoneLimestone, Marl

Nammal FormationShale,

Limestone

Paleocene

Patala FormationShale

Hangu FormationSandstone,

LateriteTriassic Mianwali Formation Limestone,

Shale and Dolomite

Permian Wargal Limestone Limestone

Warchha SandstoneSandstone,

Shale

Table No 02: List of Observed Formations

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[ ] Stratigraphy

5.3 Permian

5.3.1 Wargal Limestone

The name Wargal Limestone as approved by the Stratigraphic Committee of

Pakistan was introduced by Teichert (1966). The lithology comprises limestone and

dolomite of light to medium grey, brownish-grey, and olive grey colours. The Formation in

Zaluch Nala is 183m thick. It is not present in the study area. The contact of the Wargal

Limestone with the underlying Amb Formation is well-defined and is placed at the basal

sandy limestone of the Formation above the uppermost shale unit of the Amb Formation.

The upper contact with the Chhidru Formation is transitional. The fauna

consists of abundant bryozoans, brachiopods, bivalves, gastropods, nautiloids,

ammonoids, trilobites, and crinoids.(Fig 5.6)

F ig 5.2 Wargal L i m e s t o n e ( R oad s ec tion n e ar K hu r a vi l lage)

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[ ] Stratigraphy

Fig No 5.3 Wa r gal L i m e s t o n e ( R oad s ec tion n e ar K hu r a vi l lage)

F ig 5.4 Brachiopods and Bivalves in Wa r gal L i m e s t o n e ( At K hu r a vi l lage)

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[ ] Stratigraphy

F ig 5.5 Trilobites in Wargal L i m e s t o n e ( R oad s ec tion n e ar K hu r a vi l lage)

F ig 5.6 Sponges in Wargal L i m e s t o n e ( R oad s ec tion n e ar K hu r a vi l lage)

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[ ] Stratigraphy

F ig 5.7 Dentilina in Wargal L i m e s t o n e ( R oad s ec tion n e ar K hu r a vi l lage)

5.3.2 Chhidru FormationThe name Chhidru Formation was introduced by Dunbar (1932) which is now

formalized. The Formation at the base, as described by Kummel and Teichert (1970) has a

shale unit of pale- yellowish grey to medium dark grey in colour, the thickness of this unit

ranges from 6 to 13 m. It contains rare small phosphatic nodules. Overlying this unit are the

beds of calcareous sandstone with few sandy limestone.

The top most part of the Chhidru Formation is a white sandstone bed with

oscillation ripple marks. It is not present in the study area. Total thickness of the Formation

is about 64 m. The Formation is fossiliferous containing Ammonoids and others. (Shah,

1977).The age on the basis of the ammonoids considered to be Late Permian (Chhidman

Stage)

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[ ] Stratigraphy

Fig5.8 Chidd ru Fo r mati on (near Su rakkh i village)

5.4 Triassic

5.4.1 Mianwali Formation

The name "Mianwali Formation" was modified by Kummel (1966) after the

Mianwali Series of Gee (1959). The Formation represents a great wedge of varied

facies consisting of marl, limestone, sandstone, siltstone and dolomite which is thickest in

the west and wedges out towards the east. It is not present in the study area. The following

three members have been recognized by Kummel (1966) in the Salt Rang. (Shah, 1977)

Narmia member

Mittiwali member

Kathwai member

Kathwai Member

Member is composed of dolomite with some quartz in lower part and upper part is

composed of glauconitic limestone.

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[ ] Stratigraphy

F ig5.9 M ia n w ali f o r m a t ion K ath w ai m e m be r (ne a r Su ra k k hi v i l l ag e )

Mittiwali Member

It is the thickest member of the Formation and mainly composed of grey,

finegrained, non glacunitic limestone.

F ig5.9 M ia n w ali f o r m a t ion Mittiwali m e m be r (ne a r Su ra k k hi v i l l ag e )

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[ ] Stratigraphy

F ig5.10 M ia n w ali F o r m a tion A m m o n ite (ne a r Su ra k k hi vi l lage)

Narmia Member

It is composed of dark grey to brown sandy limestone and grey to black shales with

interbeds of sandstone and dolomite.

The lower contact with the Chhidru Formation of Late Permian age is marked by a

paraconformity which the upper contact with the Tredian Formation is sharp and well-

defined. The Formation is fossiliferous and contains brachiopods, ammonoids, nautiloids,

echinoid spines and crinoidal remains. Ammouoids species include Subvishnuites sp. indet.,

Xeno-celtites sinuatus, Xenoceltites sp., indet., Pro-carnites kokeni, Isculitoides sp. indet,,

Stacheites sp. indet., Dagnoceras sp. indet., Nordophiceras sp. indet., Nordophiceras

planorbis, Arcto-meekoceras sp. indet., Tirolites sp. indet., Pro-hungarites cf. P.

crasseplicatus. (Shah, 1977)

The fauna indicates Late Scythian age (Middle Triassic). (Shah, 1977)

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[ ] Stratigraphy

5.5 Paleocene:

Paleocene strata, in the Upper Indus Basin, are known as Makarwal Group and it

consists of following formations (Shah, 1977):

5.5.1 Hangu formation:

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

We observed it at going to Surraki village .This formation consists of dark grey

shale as shown in Fig (5.8), carbonaceous shale and nodular argillaceous limestone. The

sandstone is light grey and reddish brown, fine to coarse grained and medium to thick

bedded.

The upper contact of Hangu formation is with Lockhart formation and this contact

is transitional and conformable .But in our field area we did not observed the Lokhart

formation. Lower contact of hangu formation is unconformable with Lumshiwal

formation.On the basis of reported fauna, Early Paleocene age is assigned to the formation

(Shah, 1977).

F ig 5.11 Ha n gu F o r m at i on(sandstone) (At Rakh Khura v i l lage )

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[ ] Stratigraphy

F ig 5.12 Ha n gu F o r m at i on (Laterite bands) (At Rakh Surakkhi v i l lage)

Fig 5.13 Fire Clays of Hangu Formation (At Khura v i l lage)

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[ ] Stratigraphy

5.5.2 Patala formation:

The term Patala Formation was formalized by the Stratigraphic Committee of

Pakistan for the "Patala Shale" of Davies and Pinfold (1937) and its usage was extended to

other parts of the Kohat-Potwar and Hazara areas.

The lithology of this formation is Greenish grey/ Khaki shale’s with thin beds of

limestone. The Patala Formation has it presence in sub surface in the area. Neither lower

nor has upper contact of the Patala Formation been observed during fieldwork. The

formation is widely exposed in the Kohat-Potwar and Hazara areas.On the basis of

reported fauna, Late Paleocene age is assigned to this formation (Shah 1977).

F ig 5.14 Patala Formation (on the w ay to Noshera )

5.6 Eocene:

Eocene rocks in the Upper Indus Basin are collectively known as Charat Group

which consists of following formations (Shah, 1977):

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[CHAPTER NO 05] Stratigraphy

5.6.1 Nammal Formation:

The name “Nammal Formation” has been formally accepted by the

Stratigraphic Committee of Pakistan for the “Nammal Limestone and Shale” of Gee (1935).

During our fieldwork we observe it going to the Surraki village.It has been observed

that the formation is composed of shale and limestone (Fig 5.8). These rocks occur as

alternations. Shale’s are creamish in color and limestone of light grey color has been

observed.The upper conformable contact of the Nammal Formation has been observed

with Sakesar Limestone..On the basis of reported fauna, Early Eocene age is assigned to this

formation (Shah, 1977).

5.6.2 Sakesar LimestoneThe name “Sakesar limestone” was introduced by Gee (1935) for most prominent

Eocene limestone in Salt Range and Trans Indus ranges.

During our fieldwork we observe the formation at many places like Kathwai

,Kufri ,Chimnaki ,Khura etc

It has been observed that the formation is composed of cream to light grey

nodular massive limestone with chert nodules in the upper part (Fig 5.9).

The formation is widely distributed in the Salt Range and the Surghar Range.The

formation is highly fossiliferous. Foraminifers “Assilina, Nummulities have also been

observed in the formation.The reported foraminifers indicate that the formation is of Early

Eocene age (Shah, 1977).

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F ig 5.15 Sakesar Limestone (At the south of kufri v i l l age).

F ig 5.16 Solution holes in Sakesar Limestone (At the south of Mustufabad v i l l age).

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F ig 5.17 Chert nodules in Sakesar Limestone (At the south of Mustufabad v i l l age).

5.7 Miocene:

Miocene is collectively known as Rawalpindi Group and is represented by following

Formations (Shah, 1977):The “Kamlial Beds” of Pinfold (1918) have been formally

established as “Kamlial Formation” by the stratigraphic Committee of Pakistan..

5.7.1 Kamlial Formation

Kamlial Formation is widely distributed in field area and show Spheroidal

Weathering. Fractures and joints also can see in the Kamlial Formation (Fig 5.10) also.

During our fieldwork, it has been observed that the formation comprises friable sandstone

(Fig 5.11) and shale. Sandstone is greenish grey.Spheroidal weathering and Cross-bedding

has also been observed in Kamlial Formation.

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F ig5.18 K a m l i al F o r m a tion (At the south of kufri v i l lage).

F ig5.19 Intra formational conglomerate of K a m l i al F o r m a tion.

(At the south of kufri v i l lage)

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F ig5.20 Spheroidal weathering in K a m l i al F o r m a tion (At the south of kufri v i l lage)

5.8 Pliestocene:

5.8.1 Kalabagh Congolomerate:

Kalabagh congolomerate are also known as Kalabagh beds of Waagen (1891),

kalabagh hill conglomerate of danilchik and shah (1967) of the upper indus basin.

The Kalabagh conglomerate is essentailly regarded as a valley fill, laid down as

fluviatile, lacustrine and piedmont outwash deposits in the lower parts of the structural

depressions. The formation is composed of coarse boulder and pebble conglomerates, with

minor coarse and cross-bedded sandstone.in the Soan valley.

The conglomerate consists of poorly sorted pebbles and boulders of mostly Eocene

rocks, with a small proportion of older sedimentary rocks, quartzite and igneous

rocks.formation has not yielded any fossils .The age of the formation is considered to be

early Pleistocene.

The upper conformable contact was not observed in the area and lower

disconformable contact with Sakesar Limestone of the Formation has been observed. On

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the basis of the reported fauna, Middle to Late Miocene age is assigned to the formation

(Shah, 1977).

F ig5.21 Kalabagh Conglomerate (At kufri village).

5.9 Structures

5.9.1Fault

A fault is a planar fracture or discontinuity in a volume of rock, across which there

has been significant displacement along the fractures as a result of earth movement. Large

faults within the Earth's crust result from the action of plate tectonic forces .

5.9.2 Fault line:

` A fault line is the surface trace of a fault, the line of intersection between the fault

plane and the Earth's surface. The two sides of a non-vertical fault are known as the

hanging wall and foot wall, the hanging wall occurs above the fault plane and the footwall

occurs below the fault plain.

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5.9.3Thrust fault:

A thrust fault is a type of fault, or break in the Earth's crust across which there has

been relative movement, in which rocks of lower stratigraphic position are pushed up and

over higher strata. They are often recognized because they place older rocks above

younger. Thrust faults are the result of compressional forces.

`Thrust faults typically have low dip angles. A high-angle thrust fault is called a reverse

fault. The difference between a thrust fault and a reverse fault is in their influence. A

reverse fault occurs primarily across lithological units whereas a thrust usually occurs

within or at a low angle to lithological units.

5.9.4 Dip slope:

A dip slope is a geological formation often created by erosion of tilted strata. Dip

slopes are found on homoclinal ridges with one side that is steep and irregular (an

escarpment) and another side, the dip slope, that is generally planar with a dip parallel to

the bedding. The orientation of the dip slope is referred to as the strike. SRT dip slope lies

towards north.

5.9.5 Fold:

Folds are generally close to tight with straight limbs and small angular hinges. They

typically form in multilayers, consisting of regular alternations of beds with contrasting

mechanical properties e.g. sandstones and mudstones.Chevron folds resemble kink

bands for their planar limbs and for occurring in regularly bedded multilayers but the

hinge zones are not angular. The required distortion (rotation) is localized in the hinge

while flexural slip typically occurs, which means that individual layers of the limbs suffer

no internal distortion. As the small hinge tightens between the straight limbs, there are

space problems where holes open between competent layers. Flow of the weak interlayers,

if any, fills up these spaces

5.9.6 Slickensides:

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A slickenside is a smoothly polished surface caused by frictional movement

between rocks along the two sides of a fault. This surface is normally striated in the

direction of movement. The plane may be coated by mineral fibres that grew during the

fault movement, known as slickenf ibres, which also show the direction of displacement. In

field area slickenside are present in Sakesar formation at Khura village.

Fig No 5.22: Slickensides

5.9.7 Fault gouge:

Fault gouge is an unconsolidated tectonite with a very small grain size. Fault gouge

forms by tectonic movement along a localized zone of brittle deformation in a rock. The

grinding and milling that results when the two sides of the fault zone move along each

other results in a material that is made of loose fragments. First a fault breccia will form,

but if the grinding continues the rock becomes fault gouge.

5.9.8 Spheroidal weathering:

Spheroidal weathering is a type of chemical weathering that creates rounded

boulders and helps to create domed monoliths. This should not be confused with stream

abrasion, a physical process which also creates rounded rocks on a much smaller scale. A

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good example of spheroidal weathering can be found in the Kamlial and shows large beds

of sandstone which is friable.

F ig5.23 Spheroidal weathering in K a m l i al F o r m a tion (At the south of kufri v i l lage)

5.9.9 Ripple Marks:

Ripple marks are produced by flowing water or wave action, analogous to cross-

bedding. ripple marks are sedimentary structures and indicate agitation by water current

or waves or wind. in study area upper part of hazara group represent number of boulder

with ripple marks, which marks the paleo flow and environment of deposition .

5.9.10 Cross bedding:

Cross bedding is a feature that occurs at various scales, and is observed in

conglomerates and sandstones. It reflects the transport of gravel and sand by

currents that flow over the sediment surface (e.g. in a river channel). sand in river

channels or coastal environments When cross-bedding forms, sand is transported as sand-

dune like bodies (sandwave), in which sediment is moved up and eroded along a gentle

upcurrent slope, and redeposited (avalanching) on the downcurrent slope (see upper half

of picture at left). After several of these bedforms have migrated over an area, and if

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there is more sediment deposited than eroded, there will be a buildup of cross-bedded

sandstone layers. The inclination of the cross-beds indicates the transport direction

and the current flow (from left to right in our diagram). The style and size of

cross bedding can be used to estimate current velocity, and orientation of cross-beds

allows determination direction of paleoflow.

Fig 5.24: Cross bedding in Warchha sandstone.

5.9.11 Hummocky and swaley cross-stratification:

Hummocky and swaley cross-stratification are two closely related forms of

stratification that are generally attributed to the action of oscillating (wave-generated)

currents or combined (oscillating and unidirectional) flows. While these structures

were once thought to be omnipresent to shallow marine storm deposits, similar forms

of stratification have been recognized in both clastic and carbonate sediments of a

variety of depositional environments.This structure is characterized by internal laminae

that locally dome upward hummocks passing laterally into laminae that are concave

upward swales.

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5.9.12Flaser and Lenticular bedding:

Flaser beds are a sedimentary bedding pattern created when a sediment is exposed

to intermittent flows, leading to alternating sand and mud - currents, while the mud is

deposited during slack tide periods .the three main types of heterolithic bedding are flaser,

wavy, and lenticular.

Fig No 5.25 :Flaser Bedding

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Fig No 5.26: Lenticular bedding.

5.9.13 Drag fold:

A minor fold formed in an incompetent bed by movement of a competent bed so as to

subject it to couple; the axis is at right angles to the direction in which the beds slip.

Fig 5.27: Drag fold in sakesar limestone

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5.9.14 Dome:Dome is deformational feature consisting of symmetrically dipping anticlines. The

strata in the dome is eroded off, the series of concentric strata that grow progressively

older from the outside in which older rocks exposed in the center. This was encountered in

Sakesar Formation.

Fig No 5.28: Dome in Sakesar Limestone Khura Village

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Stratigraphy.5

Documents

salt range thrust

salt range formation

older rocks of salt

salt range of pakistan

highest peaks of salt

vast supplies of salt

base of tertiary

base of permian