12-4 Salt Tectonics and Subsurface Structural Evolution of the Missa Keswal Area, Potwar Plateau, Pakistan

Session: The Geodynamic Evolution of the Himalaya: From Mountain Building to Modern Seismicity and Climate Change

Presenting Author:

IMRAN ULLAH

Author:

ULLAH, IMRAN¹

(1) Earth Sciences, Quaid-I-Azam University, Islamabad, --seleziona--, Pakistan,

Abstract:

Salt tectonics plays a crucial role in shaping structural geometries within compressive foreland fold-and-thrust belts worldwide. In many cases, surface structures do not accurately reflect subsurface geometries, posing challenges for hydrocarbon exploration. The Salt Range and Potwar Plateau in Pakistan provide an excellent case study to understand how the Precambrian Salt Range Formation’s low-density evaporites interact with the overlying Cambrian to Holocene cover sequence under Himalayan compression. This interaction has led to the formation of multiple salt-cored anticlines, which host significant hydrocarbon reserves. 2D seismic reflection and well data from the Missa Keswal area of the eastern Potwar Plateau reveal that Paleocene strata directly overlie Cambrian rocks, with the Permian to Cretaceous units absent—an unconformity distinct from the western Salt Range and Potwar Plateau. Seismic evidence indicates basement normal faults, a northwest-dipping fore-thrust that steepens near the surface, and southeast-dipping back-thrusts forming a pop-up anticline above the basement faults. The absence of Ordovician to Carboniferous strata across the region remains debated. However, the presence of basement normal faults and missing Permian–Mesozoic sequences suggests the uplift of the eastern Salt Range and Potwar Plateau during Neo-Tethys opening in a passive margin setting. During the late Himalayan Orogeny, compressional forces mobilized the Salt Range evaporites, causing thrusting that juxtaposed Precambrian to Holocene units against the Punjab Plain along the Salt Range Thrust. The upward movement of evaporites, facilitated by basement normal faults, contributed to salt-cored, pop-up anticlines bounded by steep reverse faults. The presence of both foreland- and hinterland-verging thrusts, along with high-angle reverse faults, indicates significant crustal shortening and vertical thickening. Structural modeling using seismic and borehole data offers a reliable approach to understanding subsurface deformation and provides insights for similar salt tectonic-dominated basins worldwide.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-4456

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