TY - JOUR A1 - Ghani, Humaad A1 - Sobel, Edward A1 - Zeilinger, Gerold A1 - Glodny, Johannes A1 - Irum, Irum A1 - Sajid, Muhammad T1 - Spatio-temporal structural evolution of the Kohat fold and thrust belt of Pakistan JF - Journal of structural geology N2 - The Kohat fold and thrust belt in Pakistan shows a significantly different structural style due to the structural evolution on the double décollement compared to the rest of the Subhimalaya. In order to better understand the spatio-temporal structural evolution of the Kohat fold and thrust belt, we combine balanced cross sections with apatite (U?Th-Sm)/He (AHe) and apatite fission track (AFT) dating. The AHe and AFT ages appear to be totally reset, allowing us to date exhumation above structural ramps. The results suggest that deformation began on the frontal Surghar thrust at-15 Ma, predating or coeval with the development of the Main Boundary thrust at-12 Ma. Deformation propagated southward from the Main Boundary thrust on double de?collements between 10 Ma and 2 Ma, resulting in a disharmonic structural style inside the Kohat fold and thrust belt. Thermal modeling of the thermochronologic data suggest that samples inside Kohat fold and thrust belt experienced cooling due to formation of the duplexes; this deformation facilitated tectonic thickening of the wedge and erosion of the Miocene to Pliocene foreland strata. The spatial distribution of AHe and AFT ages in combination with the structural forward model suggest that, in the Kohat fold and thrust belt, the wedge deformed in-sequence as a supercritical wedge (-15-12 Ma), then readjusted by out-sequence deformation (-12-0 Ma) within the Kohat fold and thrust belt into a sub-critical wedge. KW - Balanced cross section KW - Fold and thrust belt KW - Duplex KW - Exhumation KW - Décollement Y1 - 2021 U6 - https://doi.org/10.1016/j.jsg.2021.104310 SN - 0191-8141 VL - 145 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Ghani, Humaad A1 - Zeilinger, Gerold A1 - Sobel, Edward A1 - Heidarzadeh, Ghasem T1 - Structural variation within the Himalayan fold and thrust belt BT - A case study from the Kohat-Potwar Fold Thrust Belt of Pakistan JF - Journal of structural geology N2 - The Kohat and Potwar fold thrust belts (KP-FTB) in Pakistan exhibit structural variations over 250 km along strike within the Himalayan fold and thrust system. Our 3D deformation model shows that Kohat surface structures evolved above an active roof thrust in Eocene evaporites. The ramp-forming duplexes in the Kohat were stacked and passively transported toward the foreland above new ramps, resulting in up to 5 km of thickening between the two decollements. Ramps from the Kohat extend into the Potwar as thrust tips of fault propagation folds. The basement slope changes from flat (beta < 1 degrees) below the northern part to north-dipping (beta > 1 degrees) below the southern part, corresponding to the change in structural style and complexity of the KP-FTB. The Kalabagh Fault Zone, linking the two belts, is interpreted as a zone of complex dextral strike-slip rotational faulting. Salt expulsed from the hanging walls of normal faults and under synclines in the Kalabagh Fault Zone moved toward the footwall of normal faults, accumulated in the cores of anticlines, and formed lobe structures at the deformation front. The fundamental reasons for the variable structural styles are changes in decollement strength, basement slope, preexisting normal faulting, presence of a secondary decollement and spatially-variable salt mobility and accumulation. KW - Fold and thrust belt KW - Decollement KW - Duplex KW - Rotational fault KW - Blind thrust Y1 - 2018 U6 - https://doi.org/10.1016/j.jsg.2018.07.022 SN - 0191-8141 VL - 116 SP - 34 EP - 46 PB - Elsevier Science Publishers Ltd. CY - Oxford ER -