THE GEOLOGY AND STRUCTURE OF NEOGENE ROCKS IN DADYAL AND ADJACENT AREAS , IN THE SUB-HIMALAYAS , AZAD JAMMU AND KASHMIR , PAKISTAN

The project area lies along the western limb of the Hazara Kashmir Syntaxis. The Hazara Kashmir Syntaxis is an antiformal structure. The project area includes Dadyal, Bihari, Ratta, Sammorthala, Samlotha, Dhingar, Panwar and Karara Saiyidan. The Late Miocene to Recent Himalayan Neogene rocks are exposed in the core of the syntaxis. These Neogene rocks include the Kamlial Formation, Chinji Formation, Nagri Formation, Dhok Pathan Formation, Soan Formation and Recent alluvium. The major folds in the project area include the Mirpur syncline, Pheran Dinpur anticline and Sadaqabad Syncline. The folds are northwest-southeast trending and southwest or northeast vergent, asymmetric and open. The only fault in the project area is Ratta Fault. The Ratta Fault is a reverse fault. The northwest southeast trending folds and faults are the result of northeast southwest Himalayan compression in the area.


Introduction
The project area in Dadyal, Mirpur district of Azad Jammu and Kashmir, Pakistan is confined in the east, west and south by the Riasi thrust, Jhelum fault and Salt Range thrust respectively (Fig. 1).The location of study area in the western limb of the Hazara Kashmir Syntaxis is shown on the tectonic map (Fig. 1).
The Nagri Formation, Dhok Pathan Formation, Soan Formation, Mirpur Formation and recent alluvium are well exposed in the area.

Materials and methods
The city, adjacent areas of Mangla reservoir, recondite places and lonely desolate valleys were surveyed in mild weather with utmost care during 30 days field work.The field photographs (Fig. 5) were taken by means of a digital camera.The rock Formations were mapped by using Brunton compass during onerous task (Fig. 3).In addition, the instrument was also used to record the attitude of bedding (Fig. 3).The route and traverse, geological and structural maps of the 75km2 area on 1:50,000 scale were compiled (Fig. 2).Moreover, the detailed structural crosssections and β and π diagrams were prepared for the structural analysis of the area (Fig. 5).The primary sedimentary structures remained helpful in the identification of the facing of rock units (Fig. 4a).The data used in structural interpretation has been enumerated in the tables 1 & 2.

Stratigraphy
The geological succession of the Dadyal and adjacent areas of Mirpur is presented in Table 3.The rocks of the project area (Table.4) are described as follows:

Siwalik Group
Meddlicot, 1864 first used the term "Siwalik" to describe the upper part of the "Sub-Himalayan System".The Siwalik Group is comprised of Neogene rocks, deposited during the Himalayan orogeny.The Siwalik Group contains arenaceous, argillaceous and conglomeratic material.The following rock sequence of Siwalik group is exposed in the project area.

Nagri Formation
The "Nagri Formation" was accepted by the Stratigraphic committee of Pakistan after Lewis (937).The Nagri Formation is mapped in Goda Sultana, Karara Saiyidan and Jinour areas (Fig. 2; Fig. 3).The sandstone and clays (60 to 40%) are the dominant lithologies of the Formation.The sandstone is greenish gray, weathered to light gray and brownish gray in outcrops.In addition, the sandstone is medium to coarse grained, hard, compact, medium to thick bedded and massive.Furthermore, the sandstone is cross bedded and exhibits salt and pepper texture (Fig. 4b).The clays vary in colour from cream to light gray.The clays are soft and friable.The mudstone and gritty clays are in scanty amount.
The minerals quartz, feldspar, biotite, epidote, muscovite, tourmaline, plagioclase and garnet coexist in the rock.The biotite is in excess amount.
The pink garnet and Panjal volcanic clasts are highly concentrated towards the top of the Formation.The clasts of granite, quartzite and marble are also disseminated in the outcrop.The formation has a high concenteration of epidote and biotite than Kamlial Formation.The formation has gradational contacts with the Dhok Pathan and Chinji Formations in the upper and lower halves respectively.
The earlier workers assigned Late Miocene age to the Formation (Shah, 2009).
The Formation is mapped in Bihari, Karara Sayidan, Khurd Piran Goda and Panwar areas (Fig. 2; Fig. 3).The sandstone, clay (50 : 50) and hard compact conglomeratic beds form the composition of rock.The sandstone is medium to coarse grained, soft, porous, friable (Fig. 4d) and less compact as compare to the sandstone of Nagri Formation.The conglomeratic levels are thick, hard and compact.The cross bedding (Fig. 4a), rip ups, lenticular bedding and ribbed topography (Fig. 4c) are the non tectonic structures of Dhok Pathan Formation.The clays are red and maroon in outcrops.The clasts vary in size from 2mm to 5cm diameter.
The minerals quartz, feldspar, muscovite, pink garnet, brown garnet, epidote, minor biotite and tourmaline form the mineral composition of the Dhok Pathan Formation.The ribbed topography (Fig. 4c) and presence of pink garnet distinguish the Dhok Pathan Formation from the rest of Formations.
The contacts with the overlying and underlying formations are gradational.However, in Ratta the formation has a faulted contact with Soan Formation (Fig 2; Fig. 3).The earlier workers declared Late Miocene age to the Formation (Shah, 2009).

Soan Formation
The Stratigraphic Committee of Pakistan has approved the name Soan Formation following Kravchenko (1964).
The sandstone, dark gray shale and conglomerates are the dominant constituents of the Soan Formation.The compact, thick, hard and massive conglomerate levels are ubiquitous near Dingar, Anb and Dadyal.The conglomerates include the pebbles and boulders of quartzite, Panjal volcanics, Murree sandstone, Paleocene-Eocene limestone, cherty dolomite and granite gneisses.The conglomerates are tesselated in arenaceous matrix (Fig. 4e).The pebbles and boulders have rounded to sub rounded outlines, few mm to 30 cm diameters and the thickness of about 0.5 meter has been paced out in the lenticular sandy layers (Fig. 4e).
The contact of Soan Formation with Dhok Pathan Formation is faulted in project area (Fig. 4h), graditional in other areas and sharp (angular) with Mirpur Formation in the Mirpur area.The earlier workers proposed Pliocene age to the Formation (Shah, 2009).

Mirpur Formation
The Formation is mapped in the Sammorthala, Ratta, Siakh, Nakai and Dadyal areas (Fig. 2; Fig. 3).The formation is a Pleistocene flood or channels fill deposit.The framework grains are loosely packed within the argillaceous matrix (Fig. 4f).The clast varies in size from 2mm to 30cm diameter (Fig. 4f).
These conglomerates followed the topography of the underlying formation and appear as a blanket over the bed rocks.The upper contact with recent alluvium and lower contact with Soan Formation are unconformable.The Mirpur Formation can be distinguished from the Soan formation by argillaceous cement.The age of the formation is Pleistocene (Shah, 2009).

Structure
The project area is surrounded by the Jhelum Fault, Riasi Fault and Salt Range Thrust in the western, eastern and southern directions, respectively (Fig. 1).The area is exposed in the south of Hazara Kashmir Syntaxis and is highly deformed by Himalayan orogeny (Fig. 1).The Hazara Kashmir Syntaxis (Fig. 1) is an antiformal structure formed by the abrupt change in northwest regional strike of the Himalayan thrust sheets to the northeast.The Main Boundry Thrust and Panjal Thrust show contortion around the Hazara Kashmir Syntaxis (Fig. 1).The folds in the project area are northwest-southeast trending, open and northeast or southwest vergent (Tables , 1 & 2).

Structure of the area
The Tertiary to Recent cover sequence of Indian Plate is deformed into folds and faults (Fig. 1).The structures is described as follows:

Folds
There are three following major folds in the area.
The Chinji and Kamlial Formations confront in the subsurface (Fig. 5, cross-sections AA′, BB′, CC′, DD′, JJ′).The strike of northeast limb displays orientation in N32°W to N79°W whereas the strike of the southwestern limb exhibits orientation in N29°W to N58°W direction.The northeastern limb of fold dips at 10°NE to 50°NE whereas the southwestern limb of fold dips at 24°SW to 40°SW (Table .1).The attitude of the axial plane is slanted in N30°W 80°SW to N72°W/77°SW directions (Table .1; Fig. 6,).
The fold axis of the anticline trend and plunge at 5°/330° to 7°/288° (Table , 1).The interlimb angle of the fold varies between 106° to 120°.On the basis of interlimb angle, the fold is classified as an open fold.The Pheran Dinpur anticline is northeast verging fold.The regional anticline is interpreted as hanging wall anticline, formed along the Ratta Fault (Fig. 5; cross sections AA′, BB′, CC′, DD′, JJ′).

Sadiqabad Syncline
The Sadiqabad syncline is a regional syncline formed by the folding of Dhok Pathan and Nagri Formations.The Dhok Pathan Formation lies in the core whereas Nagri Formation forms the limbs (Fig. 5, cross sections AA′, BB′, CC′, DD′) The strike of the northeastern limb is oriented in N26°W whereas the strike of the south western limb is oriented in N30°W direction.The northeastern limb of syncline dips at 08°SW whereas southwestern limb dips at 15°NE.The Sadiqabad syncline exhibits a trend and plunge of 0°/334°.The attitude of axial plane falls in N26°W /85°SW direction Table.2; Fig. 6).The Sadiqabad syncline has an interlimb angle of about 157° (Table, 2; Fig. 6).On the basis of interlimb angle the fold is classified as gentle fold.The Sadiqabad syncline is northeast vergent fold.
The shearing, crushing (Fig. 4h), fault breccia, gouge and drag folding are the clues of deformation along the Ratta Fault.

Faults
There is only one major fault in the area called as Ratta Fault.

Ratta Fault
The Ratta Fault is a northwest-southeast trending reverse fault and has displaced the southeastern limb of Pheran Dinpur anticline (Fig. 2; Fig. 3).In the project area, the Dhok Pathan Formation thrusts over the Soan Formation (Fig. 2; Fig. 3; cross sections AA′, BB′, CC′, DD′ and JJ′).The attitude of the hanging wall falls in N45°W/23°NE to N55°W/35°N E directions and the attitude of footwall block falls in N48°W/32°NE   The Sadiqabad syncline is a regional syncline formed by the folding of Dhok Pathan Formation and Nagri Formation.The Dhok Pathan Formation is in the core whereas Nagri Formation lies on the limbs (Fig. 2; section AA′).
The Ratta Fault is a reverse fault in the project area.The Ratta Fault is a northwest-southeast trending fault and cuts the southeastern limb of Pheran Dinpur anticline.In the project area, the Dhok Pathan Formation is thrusted over the Soan Formation (Fig. 3; cross sections, AA′, BB′, CC′, DD′ and JJ′).The attitude of the hanging wall block ranges from N45°W /23°NE to N55°W/35°NE and the attitude of footwall block is N48°W /32°NE.The attitude of the fault plane is N50°W/61°NE.The Ratta Fault is a reverse fault (Fig. 4h).
The shearing and crushing are also present along the fault zone (Fig. 4h).The fault breccia and gouge can be identified in the project area along the Ratta Fault.The drag folds are common along this fault.

Conclusion
The project area lies in the southeastern part of Hazara Kashmir Syntaxis.The Hazara Kashmir Syntaxis is an antiformal structure and the part of Himalayan foreland folds-and-thrust belt.The core of syntaxis possesses metamorphic and sedimentary rocks.The sedimentary rocks are mainly Neogene molasse deposits, formed by the late Tertiary Himalayan Orogeny.
In the project area, the thick cover sequence of sedimentary rocks ranging from Late Miocene to Recent age is exposed.These Neogene rocks are result of the collision of the Indian and Eurasian plates.The uplift of the Himalayan sediments caused erosion, transportation and deposition of these rocks in front of rising Himalayas.The project area is deformed due to the regional folds and faults.The fault is northwestsoutheast trending.The fault is reverse in nature.The folds of the area are northwest or southeast vergent and asymmetric in nature.These folds are open.These are northwest or southeast plunging folds.The major folds of the area are Pheran-Dinpur Anticline, Sadiqabad Syncline and Mirpur Syncline.
The major fault in the area is Ratta Fault.It is a splay fault of Jehlam Fault.It is a reverse fault.

Nagri Formation
Late Miocene 70% sandstone and 30% clay present.Sandstone is hard and compact, volcanic clasts are also present in upper part.Spheroidal weathering is also present.

Discussion
The project area exists in the southern part of Hazara Kashmir Syntaxis.The Hazara Kashmir Syntaxis is an antiformal structure, formed by the late Tertiary Himalayan collision between the Indian and Eurasian plates.The southeastern limb of the Hazara syntaxis is imbricated along Punjal Thrust, Main Boundary Thrust and Riasi Fault (Baig and Lawrence, 1987).The western limb of the Hazara Kashmir Syntaxis is displaced by left lateral strike slip Jhelum Fault.
The core of syntaxis is comprised of a deformed zone.The deformed zone makes a domal structure due to the layer compression (Bossart et al., 1988).The Himalayan neogene rocks form the core of syntaxis.These rocks represent the part of cover sequence of Indian plate.
The Late Miocene to recent deposits in the study area include the Nagri Formation, Dhok Pathan Formation, Soan Formation, Mirpur Formation and Recent alluvium.The area is highly deformed into regional folds and faults.The folds and faults are northwest southeast trending.The folds of the area are southwest or northeast vergent.
The folds are open to tight in nature.The major folds include Pheran Dinpur anticline, Sadiqabad syncline and Mirpur syncline.The Pheran Dinpur anticline is formed by the folding of Nagri Formation (Fig. 2; Fig. 3; Cross sections, AA′, BB′, CC' and JJ'′).The southwestern limb of

Figure 1 .
Figure 1.Regional tectonic map of the northwest Himalayas of Pakistan after (Baig and Lawrence, 1987; Monalisa and Khawaja, 2004.The rectangle shows the location of the project area.

Figure 3 .
Figure 3.The composite Geological and structural map of Ratta, Behari and Dadyal areas, District Mirpur,Azad Kashmir, Pakistan.

Figure 4 .
Figure 4. (a) Photograph showing cross bedded sandstone of Nagri Formation near Pheran (photo facing south), (b) showing salt and pepper texture in the sandstone of Nagri Formation near Pheran (Photo facing southwest), (c) Photograph showing ribbed topography (cyclic bedding) in Dhok Pathan formation near Goda (Photo facing southwest), (d) Photograph showing loosely compacted sandstone of Lower Soan Formation, Mohra Bangial (Photograph facing southwest), (e) Photograph showing lenses of tesselated conglomerate in upper Soan Formation near Siakh (Photo facing south east), (f) Photograph showing conglomerates of Mirpur Formation near Nakai (Photo facing North), (g) Photograph showing thick layer of recent alluvium near Mohra Bangial (Photo facing southwest), Photograph showing Ratta fault between Dhok Pathan Formation (A) and Soan Formation (B) near Anb (Photograph facing south).