Project rationale

The Middle to Late Permian Wargal Formation comprises of Limestone and dolomite,

which contains abundant microfauna including bryozoans brachiopods, bivalves, gastropods

ammonides, trilobites, crinoids and conodonts (Shah, 1977; Kummel and Tiechert, 1970), the

reported microflora includes pollen and spores.

The earlier investigations of the Wargal Formation were hampered by a lack of

integration of the outcrop based facies architecture and microfacies analysis for a sequence

stratigraphic modeling. Therefore present study is aimed at devising a useful tool for the

analysis of petroleum system in the sequence stratigraphic context.

1.2 Objectives

The proposed research will involve biostratigraphic and microfacies analysis of the

Wargal Formation and investigation of the sequence stratigraphic model of the unit in the Salt

Ranges, Upper Indus Basin of Pakistan.

The main objectives are as following.

Record and designate the lithofacies of the Wargal Formation in the selected key

stratigraphic sections of the study area.

Study the detailed microfacies analysis in these sections to understand

paleoenvironments of Wargal Formation.

Study the digenetic fabric and cement Stratigraphy for identification of reservoir rock

quality of Wargal Formation.

To identify depositional sequences within the sections in the basins.

To describe the paleontological and sedimentological characterization of the

depositional sequences.

1.3 Stratigraphic sections

1.3.1 Nammal Gorge Section

The Nammal Gorge Section is located near Mianwali in western Salt Range (Figure

1). The area lies in Lat. 32°39'17.4N" Long 71°E, within the Survey of Pakistan map

number……

Nammal Gorge has the best exposures of the Upper Permian, Mesozoic, and Cenozoic rocks.

The oldest rocks exposed in Nammal Gorge belong to the Permian Zaluch Group. The

Triassic MusaKhel Group overlies the Permian Zaluch Group. The boundary between the

Permian and Triassic is a Paraconformity. On top of the Triassic sequence there is a thick

succession of the Jurassic (Surghar Group) Datta Formation. There is a very thin unit of the

Samanasuk Formation. Paleocene rocks of the Nammal Gorge include (Makarwal Group)

Hangu, Lockhart and Patala Formations. The Eocene rocks include Nammal and Sakesar

Formations (Chherat Group).

1.3.2 Chidru Nala Section

The Chidru Nala Section is located near Mianwali in western Salt Range (Figure 1).

The area lies in 32°33'19" N : Long. 71°47'17.6 E, within the Survey of Pakistan map

number……

The oldest rocks in Chidru Nala belong to Precambrian to Eocene age. The Precambrian age

Salt Range Formation that is the oldest rock sequence in the area. The Tobra Formation of the

Nilawahan Group marks the base of the Permian sequence in the study area and grades

upward into medium- to coarse-grained Warchha Sandstone, whereas Dandot Formation is

missing in the area. The Warcha Sandstone is overlain by the Sardhai Formation with a

transitional contact and is placed at the top of the highest massive sandstone bed and grades

upward into the Amb Formation, which is composed of sandy limestone, gray in color and

medium- to thick-bedded. The Amb Formation having a conformable contact grade upward

into the Wargal Formation. It grades into the overlying Chidru Formation which is Para

conformably overlain by the Mianwali Formation of early Triassic age. The upper contact of

the Mianwali Formation is marked by the Tredian Formation, which consists of sandstone,

shale and dolomite. The Tredian Formation is conformably overlain by Kingriali Formation,

which is composed of dolomite and dolomitic limestone. The upper contact of the Kingriali

Formation with the Data Formation is disconformable. The Data Formation marks the base of

the Jurassic sequence and contains red, grey and white sandstone with siltstone, shale and

mudstone and fine clay horizons. It grades upward into medium-bedded limestone, marl and

sandstone of the Shinawari Formation, which is disconformably overlain by medium-bedded,

grey limestone of Samana Suk Formation. Towards top of the Jurassic sequence overlies

Chichali, Lumshiwal formations of Cretaceous age. The Cretaceous sequence is in turn

overlain by Paleocene age rocks of the Hangu, Lockhart and Patala formations, whereas the

youngest rock exposed in the area belongs the Eocene age and is represented by Nammal and

Sakessar formations.

1.3.3 Zaluch Nala Section

The Zaluch Nala section is also located near Mianwali in western Salt Range (Fig 1).

The area lies in Lat. 32°47'06.27N Long.71°38'49.0 E. The rocks exposed in the Zaluch

section ranges in age from Precambrian to Eocene. The Paleozoic rocks include Jhelum

Group of Cambrian age including continental to shallow marine sandstone. Also include

limestone and dolomite (Fatmi, 1973). The younger Paleozoic rocks include Nilawahan and

Zaluch Groups of Permian age composed of continental to marine origin mostly sandstones

and limestones (Shah, 1977). The Mesozoic rocks include rocks of Musakhel Group

(Mianwali, Tredian & Kingriali Formations) of Triassic age, the Jurassic (Surghar Group)

Datta, Shinawari and Samanasuk, Chichali, Lumshiwal and Kawagarh Formations of

Cretaceous age. These rocks belong to a wide variety of environment including fluvial,

deltaic, shallow marine and deep marine (Fatmi, 1973).

1.4 Methodology

1.4.1 Fieldwork

Detailed field excursions in the Salt Range area were carried using geological maps

available at National centre of Excellence Geology, University of Peshawar and Geoscience

Advance Research Laboratory, Geological Survey of Pakistan Islamabad. Fieldwork data

were collected in the period October 2011 to November 2011. During this period three

sections across the Salt Range area were sampled

1.4.2 Laboratory work

Most of the laboratory work was performed at National Centre of Excellence in

Geology University of Peshawar and Geoscience Advance Research Laboratory Geological

Survey of Pakistan Islamabad, but also some petrographic thin sections were prepared at the

rock thin section laboratory in the Department of Geology, University of Peshawar.

1.4.2.1 Thin sections

Petrographic thin sections were made for microfacies analysis, and were studied under

a polarizing microscope fitted with a digital camera (for details see Chapters 3 and 4).

Oriented thin sections for the study of larger benthic foraminifera were also made for

identification of species.

1.4.2.2 XRD analysis

The X-ray diffraction (powder method) is used for identification and quantitative

determination of the original mineralogy of the carbonate mineral. Furthermore,

determination of the stoichiometry of dolomites may give a clue to their origin when

combined with other information e.g. texture and association with evaporites (Morrow, 1978,

1982). X-ray diffraction data is used to determine this important feature of the Dolomite.

1.5 Graphic software

The Corel Draw X5 v15.0.0.486 Portable graphic software was used for the

construction of biostratigraphic charts, rock correlation charts, and facies model diagrams.

Study area

Fig. 2. Location map of Indus Basin of Pakistan showing oil area, gas area, condensate area and stu dy area.