Stratigraphic section of Margala Hill Limestone exposed in the Khaira Gali road section of the Hazara Basin, northwestern Himalayas has been measured, logged and sampled. The 96m thick section of Margala Hill limestone mainly consists of medium to thick bedded nodular limestone with intercalations of shale. This high resolution petrographic study of the formation has been done with an integrated approach of sedimentology, paleoecology and biostratigraphy and it mainly shows wackstone to packstone carbonate texture with different assemblages of Larger Benthonic Foraminifera e.g. (Assilina spinosa, Nummulites globulus, Ranikothalia sindensis, Nummulites mamillatus, Assilina subspinosa, Nummulites atacicus, Assilina granulosa, Operculina patalensis, Assilina laminosa, Ranikothalia nuttalli, Lockhartia conditi, Ranikothalia sahni, Lockhartia tipperi, Discocyclina dispansa, Discocyclina ranikotensis and Quinqueloculina), Bivalves and green algae. Five types of microfacies have been interpreted on the basis of carbonate texture and skeletal grains observed in thin sections. These microfacies include Rotaliids-milliolids mud-wackstone, Algal- bioclastic packstosne, Nummulitic wack-packstone, Assilinids wack-packstone and Discocyclina- Ranikothalia wack-packstone microfacies. The presence of these assemblages draws the conclusion that the deposition was occurred in closing Neo-Tethys on an inner to middle shelf environment at the northern extremity of the Indian Plate. Based on age diagnostic Foraminiferal assemblages, Ypresian, Early Eocene age has been designated to the Margala Hill Limestone.
The upper Turonian–Maastrichtian Kawagarh Formation represents a thick sequence of carbonates in the Kalachitta Range, Pakistan and it is the only stratigraphic record of Late Cretaceous sedimentation in northwestern Lesser Himalayas. Global sea-level marks a gradual fall of ∼40 to 50 m during the deposition of the Kawagarh Formation. This study is based on detailed outcrop and petrographic investigations of six stratigraphic sections exposed in Kalachitta Range. Carbonate grains are dominantly composed of pelecypods, oysters, trigonia and plankton distributed in a micritic groundmass. Five microfacies, (1) Planktonic Mudstone, Wackestone and Packstone Microfacies, (2) Pelecypodic Planktonic Mudstone and Wackestone Microfacies, (3) Pelecypodic Wackestone and Packstone Microfacies, (4) Marl Microfacies and (5) Dolostone Microfacies, were identified using distribution of faunal types and matrix. Based on faunal paleoecology, microfacies analysis and sedimentary structures, a shallow open-marine, northward-dipping ramp model has been proposed for the deposition of the Kawagarh Formation beginning with a transgressive cycle, which also corresponds to global sea-level rise, and possibly terminated by uplift owing to initial collision of the Indian Plate with the Kohistan-Ladakh Arc at the end of the Cretaceous.KEYPOINTSPaleontological and paleoecological evidence is used to develop a shallow, open-marine ramp deposition model for the Kawagarh Formation.The initiation of Kawagarh sedimentation with transgression in the late Turonian synchronise with global sea-level curve. Sedimentation was terminated by initial collision of the Indian Plate with the Kohistan-Ladakh Arc.
The Indus Basin is considered as prolific hydrocarbon-bearing province of Pakistan. The study area is located in the Middle Indus Basin. Two wells (Bagh-X-01 and Budhuana-01) were drilled in the vicinity of the study area to determine the hydrocarbon potential of the area. Both wells show no hydrocarbon reserves and are thus abandoned. The present study emphasizes two-dimensional subsurface seismic interpretation and rock physics evaluation to estimate reservoir properties of the Jurassic Samana Suk Formation. Data from nine 2-D seismic lines and two wells have been utilized to evaluate the potential. The time contour maps indicate the existence of subsurface structural features in the study area. With the help of the 3-D geological model, the faults are marked in the Samana Suk Formation and the structure is identified as a monocline. The 3-D geological modeling results also reveal that Samana Suk Formation tends to become thin in the northeast, and thick in the southwest. The petrophysical interpretation was performed to find the hydrocarbon potential of the Formation. The cross plot between P-impedance and Vp/Vs ratio shows that the lithology cannot be differentiated by the logs. Rock physics parameters such as Poisson’s ratio, bulk modulus, shear modulus, shear wave velocity, primary wave velocity, Vp/Vs ratio, and density indicate that there are no considerable hydrocarbon reserves in the Samana Suk Formation.
The research is based on the numerical study of late Cenozoic compressional events of NW Himalayas, Pakistan. The study area lies in Potwar Basin and southern Hazara Basin bounded by north dipping Salt Range Thrust (SRT) and Panjal Thrust (PT) in south and north respectively. Four major thrusts i.e. Panjal Thrust (PT), Nathia Gali Thrust (NGT), Main Boundary Thrust (MBT) and Salt Range Thrust (SRT) are considered as major discontinuities in the study area. The main objective is to observe maximum principle stress (σ1) rotation along major discontinuities and to calculate total deformation. For this purpose, 2D finite element method (FEM) technique has been adopted and Ansys Workbench 19.2 is used, which provides the facility to simulate stress along major thrusts. Material properties i.e. density (2.5 - 2.75), Young’s Modulus (70GPa, 100GPa) and Poisson’s ratio (0.25) are used to calculate the possible results. Pressure (60MPa) is applied from north and remaining sides of geometry kept fixed. The results obtained show that the direction of maximum principle stress (σ1) is N-S but also rotates at discontinuities at different angles. At some segments along of major thrusts σ1 rotates 40-45 degree and at some points it becomes parallel to the fault plane. These rotations of σ1 are due to the change in material properties and fault angles. Strike slip movement has also been found along some segments of major thrusts.
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