Structural Mapping using GIS/RS

My M.Sc thesis presentation, awaiting to be published in Anuual Technical International Conference, 2011. Wish me Luck!!!

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).
POTWAR PLATEAU
M.B.T.
Dhurnal Fault
S.R.T.
Study Area

4. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002).
POTWAR PLATEAU
• 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

5. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002).
POTWAR PLATEAU
• 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)

6. Geological map of the eastern Salt Range and Potwar Plateau modified after Jaswal et al. (2002).
POTWAR PLATEAU
• 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)

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

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
Area Square
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

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