Structural Evolution through Balanced Structural Cross-Section of North Eastern Potwar Basin, Kahuta, Kalar and Surrounding areas, Punjab, Pakistan (T-1395) (MFN 5820)

Abstract

The study area covers the Kahuta and Kalar areas in the Potwar Fold-and -Thrust Belt (PFTB), which demonstrates the Himalayan Foreland Fold-and-Thrust Belt situated at the western boundary of the Sub-Himalayas. The surface and subsurface rocks range in age from Precambrian to Recent. The Dhok Pathan and Soan formations of Pliocene to Pleistocene marks unconformity with Quaternary Terrace gravel deposits in the study area. The structural evolution of a part of the northeastern PFTB is interpreted through balanced structural cross-sections constructed by integrating seismic section of PR-92-26, structural data and well data of Kalar X-1. The cross-sections revealed the subsurface folds geometries and kinematics of thrusts which represents the deformational history of the study area. The basement was marked as prominent reflector picked at time 4.1 s or 4100 ms in seismic section PR-92-26, the equivalent depth of which is 9020 meters after time to depth conversion. The balanced cross-sections demonstrate that the folded and faulted structures present in the subsurface are formed as a result of back thrust and blind thrusts present below these structures. The anticlinal and synclinal structures are formed as detachment folds cut by thrust faults along the limbs of folds which states that these folded structures are formed prior to faulting. A 3D structural model has been generated to better understand the variation in subsurface structural geometry. The model depicts the deformation style, variation and the termination of structures across the section lines. The 3D structural model explains that the regional structures extends upto the depth of 09 km in the subsurface. The restored cross-sections shows that the average amount and percentage of shortening accommodated by structures in the study area are approximately 6 km and 29%.