Seismostratigraphic architecture of the sulaiman fold-thrust belt front (Pakistan): Constraints for resource potential of the cretaceous-paleogene strata in the east gondwana fragment

Interpretation of seismic reflection profiles tied to well controls allowed assessing the stratigraphic and structural style of the Sulaiman Fold-Thrust Belt (SFTB) including the Zindapir Anticline (ZA) and the adjacent Sulaiman Foredeep. Seismic attributes and facies analysis have shown that in the subsurface of the Sulaiman Foredeep, the presence of shallow marine shelfal deposits is seismically characterized by well-imaged prograding systems of the Paleocene-Eocene age. This same stratigraphic unit also contains packages of divergent reflections fanning towards the west, forming a prominent stratigraphic thickness expansion. The presence of prograding units and the occurrence of stratigraphic thickening are explained with a phase of accelerated subsidence, likely related to an early stage of the SFTB orogeny during the Indian Plate-Afghan Block collision that caused crustal flexure and the formation of an initial foreland basin to the east. Progressive deformation towards the east is evidenced by well-developed, 2-14 km wide, Neogene faulted detachment folds in the ZA area, that contrast with open folds of the same age observed further to the east, affecting the near surface strata. This recent deformation event may indicate the influence of the Indian-Afghan collisional tectonics during the Oligocene-Miocene. The evolution of the SFTB in this study has significant implications for exploration of new petroleum plays.

Automated summary

Interpretation of seismic reflection profiles tied to well controls has allowed for assessing the stratigraphic and structural style of the Sulaiman Fold-Thrust Belt (SFTB), including the Zindapir Anticline and the Sulaiman Foredeep. The study found evidence of shallow marine shelfal deposits in the subsurface of the Sulaiman Foredeep, with prograding systems of the Paleocene-Eocene age and packages of divergent reflections fanning towards the west. This suggests accelerated subsidence likely linked to early stages of the SFTB orogeny during the Indian Plate-Afghan Block collision, forming an initial foreland basin to the east. Further deformation towards the east, as evidenced by Neogene faulted detachment folds in the ZA area, may indicate the influence of the Indian-Afghan collisional tectonics during the Oligocene-Miocene, with significant implications for petroleum exploration.