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STRATIGRAPHIC STUDY OF AMBAR FORMATION
BY
MUHAMMAD ASLAM KHAN
Field Report Submitted To Muhammad Awais Lecturer Geology
Department, University Of Swabi.
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1.1 Ambar Formation
Ambar formation is the oldest formation exposed in the Nowshera area. The principle
lithology is light-gray to brownish-gray thin to medium bedded dolomite. The dolomite contains
cherty lenses, interbedded limestone and argillite, algal laminations and rare stromatolites. The
sharp unconformable contact with the overlying Misri Banda Quartzite lies at the top of the upper
argillite. The lower contact is concealed by Peshawar basin alluvium. The Ambar Formation is
tentatively assigned a Cambrian age based on its position below the Ordovician Misri Banda
Quartzite and lithological similarities with portions of the Cambrian Abbottabad Group. Minimum
thickness is 165 meters. It is near the Swabi-Jehangira road. Sedimentary rocks are present in the
Ambar Formation.
1.2 Study Area
Lithology of the study area was containing quartzite, sandstone and a dolerite dyke.
According to GPS data (34° 3'15.60"N and 72°24'36.40"E) satellite image of the study area is
shown in figure-1 and a field image in figure-2.
Figure-1: Satellite image of the study area.
University of Swabi
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Figure-2: Study area (Camera facing south-east direction, man is for scale having height 5 ft
and 6 inch).
1.3 Quartzite
Quartzite present there was thick bedded as compared to the sandstone beds and all the
beds were tilted or inclined towards the west direction. Thickness of quartzite beds is shown in
figure-3.
Figure-3: Quartzite beds. (Camera facing south direction, ballpoint is for scale).
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Fractures were also present in the quartzite beds which can be seen in figure-4.
Figure-4: Fractured quartzite (camera facing east direction, ballpoint is for scale).
1.4 Ripple Marks
The surface of quartzite was in wavy form which means that these are ripple marks. And
the ripple marks are formed only by ocean which gives the evidence that there was an ocean
some million years ago. Ripple marks in quartzite are shown in figure-5.
Figure-5: Ripple marks (camera facing east direction, brunton compass is for scale).
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1.5 Manganese Dendrite
In quartzite, manganese and iron particles were present. The manganese was black while
iron was red in color. Manganese dendrite is shown in figure-6.
Figure-6: Manganese dendrite (camera facing east direction, ballpoint is for scale).
1.6 Sandstone
Sandstone was also present there which were thin bedded as compared to quartzite beds.
Color of sandstone was brownish. As shown in figure-7.
Figure-7: Sandstone beds (Camera facing south direction, ballpoint is for scale).
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1.7 Dolerite Dyke
Dolerite dyke was intruded in the quartzite beds and was younger than the quartzite.
Dolerite dyke was also weathered. Dolerite dyke can be seen in figure-8.
Figure-8: Dolerite dyke (camera facing west direction).
1.8 Strike & Dip Data
The strike and dip data measured in the field is as follow:
Strike
N5E
N5E
N7E
N10E
N4E
N3E
N10E
N5E
N6E
N7E
Dip
43
42
38
38
39
57
40
43
45
44
Sense
NW
W
W
NW
W
NW
NW
W
NW
NW
The strike and dip data plotted on stereonet is shown in figure-9.
