Petroleum system, facies analysis and sedimentology of Jurassic Cretaceous of Kohat and Hazara Basin

1. PETROLEUMSYSTEM,FACIESANALYSISANDSEDIMENTOLOGYOFJURASSIC
CRETACEOUSOFKOHATANDHAZARABASIN
Fatima Qureshi (4M)
8semester 8th

2. Introduction
◦ A basin is a depression, or dip, in the Earth's surface. Basins are shaped like bowls, with sides higher than
the bottom. They can be oval or circular in shape. (Cambridge Dictionary)
◦ Here we are concerned with three prospects of study in a basin ;
◦ The long-term preserved geologic record of a sedimentary basin is a large-scale contiguous three-
dimensional package of sedimentary rocks created during a particular period of geologic time, a
'stratigraphic succession', that geologists continue to refer to as a sedimentary basin even if it is no
longer a bathymetric or topographic depression. (Cambridge dictionary)
◦ Sedimentology enquires about the origins, transport, and deposition of mineral sediment on the Earth's
surface. The subject is a link between positive effects arising from the building of relief by tectonics and
the negative action of denudation in drainage catchments and tectonic subsidence in sedimentary basins.

3. Introduction
◦ Facies analysis is an essential method for reconstructing paleo-depositional environments and for
understanding broader aspects that influence the evolution of a sedimentary basin, such as the subsidence
history and the underlying climatic conditions. (Cambridge dictionary)
◦ Petroleum systems occur in reservoirs within sedimentary basins—those areas of the world where
subsidence of the Earth’s crust has allowed the accumulation of thick sequences of sedimentary rocks.
◦ Geologists sometimes use the phrase “petroleum systems analysis” to describe the type of studies that
must be made to determine whether a region should be expected to contain accumulations of
hydrocarbons.
◦ Jurassic and cretaceous rocks are points of interest for petrophysics and geologists because of their
depositional environment and their potential to produce hydrocarbons. Moreover abundance of fossils in
these rock helps paleoclimatologists to study past environments and predict future.

4. Tectonic
Framework of
Hazara Basin
Figure 1.1 Rahman et al (2017)
Regional tectonic map of Pakistan and stratigraphic setting of Hazara Basin.

5. Tectonic Map
of Kohat
Plateau
Figure1.2 Paracha .W (2004)
It includes the geological trend and petroleum system in Kohat Basin.

6. Stratigraphic
Column of
Hazara basin
Figure 1.3; Ghazi .S et al. (2021)
Stratigraphic column of hazard basin showing lithologies and litho-facies

7. Stratigraphic
Column of
Kohat Basin
Figure 1.4. Hussain .M et al (1974)
Stratigraphic column of Kohat sub basin sowing lithologies Precambrian to cretaceous

8. Datta Formation (Kohat sub basin)
Marai Bala
◦ The formation has been divided into an upper and lower
members.
◦ The lower member has been exposed thickness of 695
feet of dark-gray limestone which is dense to very
finely crystalline but in places is coarsely crystalline
◦ The upper member is 485 feet thick and is composed of
dark-gray or brownish-gray limestone which is dense to
very finely crystalline, in places coarsely crystalline and
oolitic. Beds are a few inches to 3 feet thick.
◦ Both the lower and upper members contain layers of
megafossil fragments, suggesting shallow-water
deposition. The members form steplike scarps.
Mazari Tang
◦ The Datta Formation is 602 feet thick and is
composed of brownish- to yellowish gray, dense
to very finely crystalline limestone in beds a few
inches to 3 feet thick.
◦ The limestone has thin shale partings toward the
bottom and contains layers of megafossil
fragments.
◦ A red shale facies believed to be of the Datta
Formation is present near Sulaiman Khel, A
sandstone and shale facies of the Datta Formation
is present on the north-central flank of the Kohat
Range.

9. Datta Formation ( Hazara Section)
Northern Hazara
◦ In the northern part of the Hazara Basin the Datta
Formation rests directly on the Cambrian sequence of the
Hazira Formation.
◦ In the Salt Range the Datta Formation (e.g. Shah, 1977)
is (about 150m thick) and of continental origin
containing plant remains and carbonaceous matter and
giving a variegated color.
◦ Today it changes to a marine facies.
◦ It is not exposed in the Khanpur Dam section.
◦ Chaudhry and Ahsan (1999a) grouped the above
mentioned microfacies of the Datta Formation under
four standardized lithofacies that include carbonate
facies, argillaceous facies, arenaceous facies, and
ferruginous hardground facies.
Southern Hazara
◦ The Datta Formation in the south-east Hazara is
composed (Chaudhry and Ahsan, 1999) of gritty
sub lithic arenites, gritty arenites, arenaceous
limestones, bioclastic wackestone, oolitic and
pelletoidal wackestones – packstones with
occasional dolomitic, marly and shaly horizons.
◦ The sandstones are cross-bedded at places.
Microconglomerate occurs in the basal portion
and contains slate clasts derived from the
underlying Hazara Formation. Laterite bands and
coaly layers occur at places. Fireclay is also
intercalated at places.

10. Shinawari formation (Kohat Area)
Type Locality Litho-facies
◦ Shinwari Formation Shinwari Village, District
Karrak
◦ The formation consists of thin to thick bedded
grey, brownish grey limestone that includes
sandy, oolitic and ferruginous beds.
◦ Nodular marl, calcareous and non calcareous
maroon shale and quartzose, ferruninous and
calcareous white to light grey, brown
sandstone.
Fossil Content
◦ The fossils recorded are Bouleiceras,
Terebratula, Montlivaltia, Pholadomya,
Zeilleria, Eotrapezium, Spiriferina sp., Velata
velata, Pecten sp., Lima gigantee, corals
gastropods, bivalves and brachiopods.

11. Samanasuk formation (Kohat Area)
Locality and litho-facies
◦ The Upper Jurassic Samana Suk Limestone was
first named by Davies (1930, p. 3) for rocks in the
Samana Range near Hangu in the Kohat District.
◦ This cliff-forming Limestone is dark gray to
brownish gray and dense to very finely crystalline.
Beds are 5 to 10 feet thick, well-jointed, and have
pitted surfaces.
◦ The upper contact of the Samana Suk Limestone
with the Chichali Formation is unconformable and
in places is marked by an irregular ferruginous
weathered surface.
Fossil
◦ At Marai Bala the formation is 505 feet thick.
The basal 25 feet consists of platy limestone.
◦ The uppermost beds are oolitic and in places
contain Foraminifera (Bolivina, Rotalia, Nau~
tiloculina neolithic) and megaf ossil fragments.

12. Samanasuk formation (Hazara Area)
locality Envoirnment Color lithology Fracture facies
It was
observed in
Mera rehmat
khan section.
The Samana
Suk Formation
(Shah, 1977)
generally
represents an
epicontinental
intertidal
environment.
The formation is
generally
medium grey on
fresh surface,
the limestone
shows a
brownish tinge
on a weathered
surface.
It is well bedded and
the individual beds
being generally 40 cm
to 60 cm in thickness.
Some parts show
thick intercalations of
thinly bedded marl or
shale between
massive beds
Yellow dolomitic
patches, streaks, and
bands are present
especially towards the
lower and middle
parts
The limestone
shows
conchoidal
fracture.
Oolites, pellets and intraclasts are
common alongwith or without
bioclasts. They are generally
difficult to recognize in the Ayubia
area. Oolites are well developed
near the base and top.
. Gastropods and pelecypods
oyster-bearing beds occur
frequently. Horizontal, inclined,
vertical and U-shaped burrows are
common.
The matrix contains
sub-rounded to
subangular detritial
quartz grains.
Laterite encrustations are dark brown to
blackish brown and occur at most places.
Scours are now filled with dolomite and
are augen shaped.

13. Samanasuk
formation( Hazara
Area )
Figure1.5; Tariq. H et al (2022)
Outcrop photographs of the Samana
Suk Formation show the different
patterns of dolomitization..
. B
An inset image shows the
dolomitization patterns observed.
C
Inset image of patchy brown
dolomites after stratification.
D
Detailed view of strata-bound
dolostone and patchy dolostone in
contact with the host limestone.
E
Burrows are filled with brown
dolomite as a result

14. Chichali formation (Kohat Area)
Locality and Litho-facies
◦ Chichali Formation Chichali Pass, District Karrak
◦ The formation consists of dark green, greenish grey,
weathering rusty brown, glaconitic sandstone dark grey,
bluish grey, greenish grey, sandy, silty, glauconitic shale
with phosphatic nodules in lower parts. At Chichali pass,
it is sufficiently rich in iron to form a low grade iron ore.
◦ This formation is well exposed at the Mazari Tang
section. It is 92 feet thick and is composed of dark green
coarse-grained soft sandstone containing glauconite.
◦ The outcrop of the formation is often stained yellowish
brown. It forms a slope and bench above the cliff-
forming Jurassic limestones. The upper contact of the
Chichali Formation is conformable with the Lumshiwal
Sandstone.
Fossil content
◦ It contains Perisphinctes, P. Mayaites,
Belemnopsis gerardi, Aspidoceras,
Physodoceras sp., Katroliceras cf., pottingeri,
Pachysphinctes robustus, Aulacossphincytoides
sp., Virgatosphinches, Proniceras indicum,
Neocomites, Berriasella, Spiticeras. Kilianella,
Olcostephanus and Lyticoceras.
◦ . The formation is crowded with belemnites,
and A. N. Fatmi (oral commun., 1965) of the
Geological Survey of Pakistan has collected
diagnostic Early Cretaceous ammonites.

15. Chichali Formation ( Hazara Area )
Locality and litho-facies
◦ The formation is composed of blackish grey to grey
splintery shale. It weathers to brownish black to rusty
grey shades. However, khaki colored shale belonging to
this formation is exposed near Harno.
◦ Ferruginous concretions, silver yellow pyrite nodules
with rusty brown to rusty black weathering are also
present.
◦ At places, shale contains rounded or elliptical variegated
clayey nodules with concentric layers.
◦ At places, subordinate beds of sandstone are present.
Petrographically, sandstone is composed of arenites that
are cemented with quartz, calcite, clay or glauconite.
Quartz is fine to coarse grained.
◦ Glauconitic horizons are also present in places.
Environment and fossils
◦ Parts of Chichali Formation are fossiliferous
(Iqbal and Shah, 1980) and in Hazara Basin it
hardly contains fossils.
◦ The formation was deposited in a restricted
anoxic environment during Oxfordian to
Kimmeridgian time (Shah, 1977). The lithified
sedimentation rates are 2.3mm/1000 year
(Chaudhry et al., 1998a).

16. Chichali
Formation
( Hazara Area )
Figure 1.6 ;Fazal, A. G .(2022)
Field photographs of
the Chichali
Formation:
(A,B) Yellowish
brown to grey shales
(Section 1),
(C–E) organic-rich
shales (Section 2),
(F–H) light to dark
brown shales with
interbedded marl and
sandstone (Section
3).

17. Lumshiwal formation (kohat Area )
Locality and litho-facies
◦ Lumshiwal Formation Lumshiwal Nala,
District Mianwali
◦ It consist of thick-bedded to massive, light
grey, current-bedded sandstone with silty,
sandy,
◦ glauconitic shale towards the base and
feldspathic, ferruginous and contains
carbonaceous material in the upper part in the
Samana range it consists of fine to coarse-
grained grey, brown, quartzose sandstone with
silty clay partings.
Fossil content
◦ It contains bivalves, gastropods, ammonoids
(Douvilleiceras mammilatum, Oxytropidoceras
spp., Desmoceras sp., Cleoniceras sp.,
Brancoceras sp., Lemunoceras sp.,
Ammonitoceras sp., Pseudosaynellid,
Deshayesitids, Virgatosphinctes), belemnites
and echinoids.

18. Lumshiwal formation ( Hazara Area)
Locality and Litho-facies
◦ Ahsan and Chaudhry (1999) presented a comprehensive study of the
Lumshiwal Formation of Hazara Basin.
◦ The formation is composed of glauconitic arenite, quartz wackes,
arenaceous limestone, arenaceous dolomites and oolitic limestones.
Shales/marls are minor. Diastems at places are marked by submarine
hard-grounds.
◦ These horizons are cemented with iron oxides and may occasionally
contain cellophane or dahalite. Heavy mineral suit indicates derivation
from a low relief area on the Indian Shield to the south
◦ Chaudhry et al. (1998b) and Ali et al. (2000) described twelve
lithofacies from Kundla that include lower grey sandstone facies,
fossiliferous limestone facies, phosphatic glauconitic sandstone facies,
sandy shale/carbonaceous sandstone facies, lower grey sandstone
facies, silty sandstone facies, green sandstone facies, light grey
sandstone facies, carbonaceous sandstone facies, hardground facies,
upper grey sandstone facies, and grey arenaceous carbonate facies.
Environment and fossil content
◦ Strongly reducing conditions changed to a
mildly reducing environment with better
circulation in the Thithonian to deposit the
Lumshiwal Formation (Ahsan et al. 2001c)
◦ It contains oysters in abundance.

19. Figure 1.7: Rahim. W, Latif. W et al(2022)
Depositional model of Lumshiwal formation (Hazara area)

20. Kawagarh formation ( kohat Area)
Locality and Litho-facies
◦ Kawagarh Formation Kawagarh Hills, District
Attock
◦ It consist of dark marl and cleaved calcareous
shale which weather light grey, brownish grey and
nodular argillaceoes limestone in westerly
exxtension and on eastern side dolomitic
limestone occurs.
◦ Tsukail Tsuk Menber:- A grey thick to massive
bedded, excarpment forming limestone.
◦ Chalor Silli Member:- A light grey, olive grey
medium bedded limestone with shale and marl
intercalation.
Fossil content
◦ The formation is poor in mega fossilshowever
collignoceratid ammonoids are recorded.
◦ Also smaller foraminifers including different
species of Globotruncana (G. lapparenti, G.
fornicata, G. concavata carinata, G. elevata-
calcarata), Heterohelix reussi, H.
globocarinatam H. globulosa.

21. Kawagarh formation (Hazara Area)
Locality and Lithology
◦ One of the tectonically significant formations of the Hazara
Basin, the Kawagarh Formation, shows two distinct facies
(Ahsan and Chaudhry, 1998) north and south of the
Nathiagali Fault. The northern facies are exposed near Giah
(Chaudhry et al., 1992a), Borian (Ahsan et al., 1993a) and
Kala Pani (Ahsan et al., 2001a) whereas the southern facies
outcrop at Changla Gali (Ahsan et al., 1994) Jabri (Ahsan et
al., 1993b) and Khanpur Dam area.
◦ The Kawagarh Formation in the sections north of the
Nathiagali Fault is mainly thick bedded, fine gained and
medium to dark grey limestone.
◦ South of the Nathia Gali Thrust the upper part of Kawagarh
Formation is marly and intercalations of marl are also
present.
Fossils and Microfacies
◦ Plankton foraminifera, shelly fauna and calcispheres are
the major skeletal components of the Kawagarh
Formation. Filaments, echinoids, ostracods, bryozoans
and textularia constitute the shelly fauna that occur as
skeletal debris.
◦ The study of the Kawagarh Formation in the Hazara
Basin shows that it is generally composed of seven
microfacies (Ahsan, 2008) that include Planktonic
foraminiferal-calcispheres wackestone (and Packstone),
Planktonic foraminiferal-shelly faunal wackestone (and
packstone), Shelly faunal mudstone and wackestone (and
packstone), Calcispheres-planktonic foraminiferal
wackestone (and packstone), Dolostone, Planktonic
foraminiferal wackestone (mudstone and packstone) and
Marl

22. Jurassic cretaceous petroleum system in
Kohat
◦ Reservoir rocks
◦ Datta Formation from the study area ranges from l.57 to 11.54 with an average porosity of 5.96 % while
measured permeability ranges from 0.000 to 8.64 MD with an average permeability is 1.70 mD.
◦ The petrophysical analysis shows that in the Chanda deep-01, the calculated total porosity and effective
porosity of Datta formation is 2.72% and 2.22% respectively while in In Chanda-01, the calculated total
porosity and effective porosity ofDatta formation is 2.24% and 1.75% respectively
◦ The best reservoir quality is present in the middle and upper part of the Datta Formation. The Datta
Formation beds in the study area are thick enough with suitable porosity and permeability values, which
could be good targets for hydrocarbon exploration in future.
◦ From cretaceous it is lumshiwal sandstone ( 12-16 % porosities )
◦ Chichali and lumshiwal are the most potential source rocks thorought the kohat plataue.Vitrinite
reflection for cretaceous 0.6 to 1.1 , Jurassic 0.5 to 0.9

23. Petroleum prospective
of kohat-potwar basin
Figure1.8 Kazmi and Rama, (1982)
Generalized petroleum map of kohat-potwar basin

24. Jurassic cretaceous petroleum system in
Hazara area.
◦ In southeast Hazara, the folds are found to be tight to overturned and the cores of the folds are usually
occupied by competent Samana Suk Formation. The organic rich horizons were observed in the field
within the Formation, the TOC of which was calculated as 0.28%.
◦ Microfacies analysis reveals well sorted and well-rounded ooidal-peloidal grainstones and packstones as
well as dolomitized and fractured wackestones and mudstones. The diagenetic signatures include
fracturing and dolomitization depicting its source and reservoir quality for a hydrocarbon prospect.
◦ Kawagarh formation in Hazara area shows in image J porosity analysis, the porosity is found in
limestone and dolomitic samples. In limestone facies which is mostly, non-laminated mudstone has very
low up to 2 to 3% in the form of vugs and fractures. In dolomitic facies, the porosity is ranging from 5%
to 14%. In most of the dolomitic samples, the porosity is around about 5%.
◦ Chichali formation is producing coal in Hazara area and thought to be producing hydrocarbons
potentially

25. References
◦ Umar, M., Sabir, M. A., Farooq, M., Khan, M. M. S. S., Faridullah, F., Jadoon, U. K., & Khan, A. S. (2014a).
Stratigraphic and sedimentological attributes in Hazara Basin Lesser Himalaya, North Pakistan: their role in
deciphering minerals potential. Arabian Journal of Geosciences, 8(3), 1653–1667.
https://doi.org/10.1007/s12517-014-1322-1
◦ Meissner, C. R., Master, J. M., Rashid, M., & Hussain, M. (1974). Stratigraphy of the Kohat Quadrangle, Pakistan.
Semantic Scholar. https://doi.org/10.3133/PP716D
◦ Qamar, S., Mumtaz Muhammad Shah, Hammad Tariq Janjuhah, Kontakiotis, G., Shahzad, A., & Evangelia
Besiou. (2023). Sedimentological, Diagenetic, and Sequence Stratigraphic Controls on the Shallow to
Marginal Marine Carbonates of the Middle Jurassic Samana Suk Formation, North Pakistan. Journal of Marine
Science and Engineering, 11(6), 1230–1230. https://doi.org/10.3390/jmse11061230