The document presents a structural investigation of the eastern salt range in Punjab, Pakistan, focusing on its geological formations and tectonic history. Utilizing GIS and remote sensing methods, it maps significant geological features, including major thrusts and folds, revealing the area's history of compression and deformation. Key findings include the identification of forethrusts and backthrusts, with implications for understanding the region's tectonic processes and stratigraphic layers.

1. STRUCTURAL INVESTIGATION OF A PART OF EASTERN SALT RANGE USING GIS/RS NEAR DOMELI TOWN, PUNJAB, PAKISTAN UMER KHAYAM WAQAS NAWAZ JODUT REHMAN SOHAIL FAREED BABAR SADDIQUE

2. OVERVIEW Our thesis area is located in the eastern part of the Salt Range Salt Range encompasses the southern portion of the Potwar Plateau This plateau is bounded on the east and west by Jhelum and Indus rivers respectively and in the north by Main Boundary Thrust Our area comprised of majorly Eocene to Miocene and Pliocene stratigraphy with structures heavily influenced by the complex tectonic history of the whole plateau

3. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002). M.B.T. Dhurnal Fault S.R.T. POTWAR PLATEAU Study Area

4. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002). The Southernmost part of the Potwar Plateau Formed as a result of ramping up of a basal decollment in the Pre Cambrian Salt Range Formation According to Baker (1988), the eastern Salt Range exhibits the geometry of a fault bend fold POTWAR PLATEAU

5. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002). Limited by the Salt Range in the south and Soan Backthrust in the north Developed first as an autochtho- nous part of Himalayan foreland Basin Later on transformed into a piggy back basin when its own basal decollement was activated (Lillie et al; 1997) POTWAR PLATEAU

6. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002). A narrow zone between Main Bo- undary Thrust in the north and Soan Backthrust in the south At surface it is mainly covered by the Murree Formation of Miocene Age Siesmic interpretation suggest that a stack of imbricated thrusts is present underneath (Jaswal et al; 1997) POTWAR PLATEAU

7. LOCATION OF THE STUDY AREA 12 km NW N5 Highway Dina

8. METHODOLOGY The mapping technique we used was Remote Sensing to reconfirm the Points of Interest in the field Area co-ordinates were plotted in the Google Earth software and boundaries were drawn The area marked in the Google Earth was then transferred into Global Mapper, a GIS software Digital Elevation Modelling (DEM) method was used to generate a contour map of the area. Furthermore, this method was also incorporated while drawing the profile line for the cross sections

9. METHODOLOGY All the important contacts and structural features were marked in the field, orientation noted, and saved in the GPS device as Points of Interest (POI’s) Later on these POI’s were transferred to Google Earth software on the marked area along with the description On Global Mapper the orientation related to each POI is plotted and the structures are demarcated POI’s with similar information on different traverses were joined together in the Google Earth along with the additional visual aid of the color of formations

10. METHODOLOGY After a final trace out of the map is completed in the Google Earth with the contacts, fold axis, faults and other minor structures marked, it is finally drawn in any graphical software (Corel Draw for instance) For cross sections, DEM was used to generate the profile line and the formations were plotted with their respective contacts and orientations Some of the graphics in the whole process are presented in the coming slides

11. DIGITAL ELEVATION MODELING (DEM) Digital Elevation Modeling (DEM) of the study area. Black dots (POIs) show the measuring stations in the field. Different heights are represented by their respective colors in the scale. Orange lines mark the outline of our study area Generated by: Global Mapper V. 12

12. TRAVERSES ALONG WITH POI’S Google Earth image of the study area. Outline of the area has been geographically referred by using GPS field data. Pins (POI) show the measurement stations in the field while the yellow lines are the traverses Area Square

13. REGIONAL TECTONICS SUMMARY Map of Northern Pakistan showing subdivisions of Himalayas. Modified after Coward et al, 1988. Inset represents the study area

14. STRATIGRAPHY OF THE AREA Stratigraphic column of the study area

15. Illustration showing the limestone of Chorgali Formation Illustration showing the sandstone of the Murree Formation

16. Illustration showing the purplish conglomerate and reddish sandstone of the Kamlial Formation Illustration showing grey-green sandstone and pinkish clays of Chinji Formation

17. Illustration showing the sandstone of Nagri Formation Outcrop of clays in the Dhok Pathan Formation. In pre-set alternate sandstone and clays can be seen

18. STRUCTURAL GEOLOGY The study area lies at the eastern extension of the Salt Range and mostly represents northeast-southwest trending ridges showing northwest-southeast compression Since the study area represents the eastern portion of SRT (Salt Range Thrust), this thrust has deformed the area to various extents From south to north, the major structures controlling the subsurface geometry are as follows; Kalra Thrust Domeli Thrust Kalra Anticline Domeli Anticline Pamaal Back Thrust

19. GEOLOGICAL MAP OF THE AREA

20. KALRA ANTICLINE While traversing from south to north in the study area, the first major structure encountered in the southern part of the area is the Kalra Thrust Along this thrust the older Chinji Formation of late Miocene age is thrusted over the younger Dhok Pathan Formation of Late Pliocene age The hanging wall thus contains Chinji Formation and the Dhok Pathan Formation lies in the foot wall The Kalra Thrust strikes S52 o W with dip direction of 20 o NW and its dip ranges from 70 o to 75 o

21. KALRA ANTICLINE Photograph showing the Kalra Thrust between Moicene Chinji Formation and Pliocene Dhok Pathan Formation (northwest view)

22. DOMELI THRUST Along this thrust, the rocks including Murree Formation of the Early Miocene age and the Eocene Chorgali Formation (representing Oligocene unconformity) are thrusted over the Late Miocene Chinji Formation Murree Formation and Chorgali Formation thus occur along the hanging wall and Chinji Formation lies in the foot wall portion This thrust is northeast-southwest oriented with numerous undulations and bends representing dip amount of 85 o to 87 o

23. DOMELI THRUST Photograph showing the Domeli Thrust between Chinji Formation and Murree Formation (northward view)

24. KALRA ANTICLINE This anticline occurs to the north of the Domeli Thrust. It is a major anticline in the area exposing Chorgali Formation in its core Its southern limb coincides with the Murree Formation along the Domeli Thrust. Chorgali Formation is folded because of the Domeli Thrust The trend of the hinge line of the fold is 225 0 and it plunges westward; coinciding with the Pamaal backthrust

25. KALRA ANTICLINE Photograph showing the northward dipping limb of Kalra Anticline (southeast view)

26. DOMELI ANTICLINE Domeli Anticline is the northernmost major structure in the northern part of the study area Succeeding an intraformational syncline, it represents a huge fold within the Murree Formation The southern limb dips steeply while the northern limb is gentle. The trend of the hinge line of this fold is 40 o towards northeast

27. DOMELI ANTICLINE Photograph showing the northward dipping limb of Domeli Anticline. Fold axis has been eroded (northward view)

28. PAMAAL BACKTHRUST Pamaal backthrust coincides with the westward plunging Kalra Anticline and has brought the Chorgali Formation above the Murree Formation in the opposite direction with respect to the major Domeli Thrust Pamaal backthrust emplaces southward dipping beds of Chorgali Formation in contact with the northward dipping beds of Murree Formation along the Domeli Thrust Thus, Murree Formation lies in the footwall and the Chorgali Formation occupies the hanging wall Dip amount along this thrust is 55 o to 58 o towards south

29. PAMAAL BACKTHRUST Photograph showing the Pamaal Backthrust (northeast view); limestone beds dipping southwards

30. CROSS SECTION ALONG LINE AB OF MAP

31. CROSS SECTION ALONG LINE CD OF MAP

32. CONCLUSIONS Domeli area, being located in the eastern Salt Range has undergone severe deformation because of its association with the Salt Range Thrust in the south and Main Boundary Thrust in the north The major trend of the structures in the study area is northeast-southwest, which indicates that the area has undergone northwest-southeast compressional deformation Two major forethrusts (Kalra and Domeli) and a backthrust (Pamaal) are mapped in the study area The forethrusts are southeast verging while the backthrust is northwest verging

33. CONCLUSIONS The major tectonic transport direction is southeast Major anticlines of the area are Domeli Anticline exposing Miocene age Murree Formation in its core and Kalra Anticline which lies to the south of Domeli Anticline and exposes Chorgali Formation in its core Based on the attitude data of the limbs of Domeli Anticline, it is concluded that the fold is partially overturned and hence is asymmetrical

34. CONCLUSIONS The unusual greater thickness of the Murree Formation in the northern limb of the Domeli Anticline can be attributed to a couple of blind thrusts which terminate at the level of Murree Formation in the subsurface The intensity of thrusting is higher towards the eastern portion of the study area bringing Eocene carbonates to the surface along the Domeli Thrust, while the thrusting is comparatively less intense in the western half of the study area as Eocene rocks are not exposed there